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Thomas Henry Huxley
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Title: Man's Place in Nature and Other Essays
Author: Thomas Henry Huxley
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Language: English
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EVERYMAN'S LIBRARY
EDITED BY ERNEST RHYS
SCIENCE
HUXLEY'S ESSAYS
WITH AN INTRODUCTION BY
SIR OLIVER LODGE
THE PUBLISHERS OF _EVERYMAN'S
LIBRARY_ WILL BE PLEASED TO SEND
FREELY TO ALL APPLICANTS A LIST
OF THE PUBLISHED AND PROJECTED
VOLUMES TO BE COMPRISED UNDER
THE FOLLOWING TWELVE HEADINGS:
TRAVEL SCIENCE FICTION
THEOLOGY & PHILOSOPHY
HISTORY CLASSICAL
CHILDREN'S BOOKS
ESSAYS ORATORY
POETRY & DRAMA
BIOGRAPHY
ROMANCE
[Illustration]
IN TWO STYLES OF BINDING, CLOTH,
FLAT BACK, COLOURED TOP, AND
LEATHER, ROUND CORNERS, GILT TOP.
LONDON: J. M. DENT & CO.
[Illustration: HOC SOLUM SCIO QUOD NIHIL SCIO]
MAN'S PLACE
IN NATURE
AND OTHER
ESSAYS BY
THOMAS
HENRY
HUXLEY
[Illustration]
LONDON: PUBLISHED
by J. M. DENT. & CO.
AND IN NEW YORK
BY E. P. DUTTON & CO.
_First Edition, February 1906_
_Reprinted July 1906_
CONTENTS
PAGE
I. ON THE NATURAL HISTORY OF THE MAN-LIKE APES 1
II. ON THE RELATIONS OF MAN TO THE LOWER ANIMALS 52
III. ON SOME FOSSIL REMAINS OF MAN 111
IV. THE PRESENT CONDITION OF ORGANIC NATURE 151
V. THE PAST CONDITION OF ORGANIC NATURE 168
VI. THE METHOD BY WHICH THE CAUSES OF THE PRESENT
AND PAST CONDITIONS OF ORGANIC NATURE ARE TO
BE DISCOVERED.--THE ORIGINATION OF LIVING BEINGS 186
VII. THE PERPETUATION OF LIVING BEINGS, HEREDITARY
TRANSMISSION AND VARIATION 208
VIII. THE CONDITIONS OF EXISTENCE AS AFFECTING
THE PERPETUATION OF LIVING BEINGS 225
IX. A CRITICAL EXAMINATION OF THE POSITION OF MR.
DARWIN'S WORK, "ON THE ORIGIN OF SPECIES," IN
RELATION TO THE COMPLETE THEORY OF THE CAUSES
OF THE PHENOMENA OF ORGANIC NATURE 245
X. ON THE EDUCATIONAL VALUE OF THE NATURAL
HISTORY SCIENCES 264
(Lecture delivered at St. Martin's Hall,
July 22, 1854).
XI. ON THE PERSISTENT TYPES OF ANIMAL LIFE 283
(Lecture delivered at the Royal Institution,
June 3, 1859.)
XII. TIME AND LIFE 287
(_Macmillan's Magazine_, December 1859.)
XIII. DARWIN ON THE ORIGIN OF SPECIES 299
(_Westminster Review_, April 1860.)
XIV. THE DARWINIAN HYPOTHESIS 337
(_Times_, December 26, 1859.)
XV. A LOBSTER; OR, THE STUDY OF ZOOLOGY 352
(Lecture delivered at South Kensington
Museum, May 14, 1860).
INTRODUCTION
Forty years ago the position of scientific studies was not so firmly
established as it is to-day, and a conflict was necessary to secure
their general recognition. The forces of obscurantism and of free and
easy dogmatism were arrayed against them; and, just as in former
centuries astronomy, and in more recent times geology, so in our own
lifetime biology, has had to offer a harsh and fighting front, lest its
progress be impeded by the hostility born of preconceived opinions, and
by the bigotry of self-appointed guardians of conservative views.
The man who probably did as much as any to fight the battle of science
in the nineteenth century, and secure the victory for free enquiry and
progressive knowledge, is Thomas Henry Huxley; and it is an interesting
fact that already the lapse of time is making it possible to bring his
writings in cheap form to the notice of a multitude of interested
readers. The pugnacious attitude, however, which, forty years ago, was
appropriate, has become a little antique now; the conflict is not indeed
over, but it has either totally shifted its ground, or is continued on
the old battlefield chiefly by survivors, and by a few of a younger
generation who have been brought up in the old spirit.
The truths of materialism now run but little risk of being denied or
ignored, they run perhaps some danger of being exaggerated. Brilliantly
true and successful in their own territory, they are occasionally pushed
by enthusiastic disciples over the frontier line into regions where they
can do nothing but break down. As if enthusiastic worshippers of
motor-cars, proud of their performance on the good roads of France,
should take them over into the Sahara or essay them on a Polar
expedition.
That represents the mistake which, in modern times, by careless
thinkers, is being made. They tend to press the materialistic statements
and scientific doctrines of a great man like Huxley, as if they were
co-extensive with all existence. This is not really a widening of the
materialistic aspect of things, it is a cramping of everything else; it
is an attempt to limit the universe to one of its aspects.
But the mistake is not made solely, nor even chiefly, by those eager
disciples who are pursuing the delusive gleam of a materialistic
philosophy--for these there is hope,--to attempt is a healthy exercise,
and they will find out their mistake in time; but the mistake is also
made by those who are specially impressed with the spiritual side of
things, who so delight to see guidance and management everywhere, that
they wish to blind their eyes to the very mechanism whereby it is
accomplished. They think that those who point out and earnestly study
the mechanism are undermining the foundations of faith. Nothing of the
kind. A traveller in the deck-cabin of an Atlantic liner may prefer to
ignore the engines and the firemen, and all the machinery and toil which
is urging him luxuriously forward over the waves in the sunshine; he may
try to imagine that he is on a sailing vessel propelled by the free air
of heaven alone; but there is just as much utilization of natural forces
to a desired end in one case of navigation as in the other, and every
detail of the steamship, down to the last drop of sweat from a fireman's
grimy body, is an undeniable reality.
There are people who still resent the conclusions of biology as to man's
place in nature, and try to counteract them; but, as the late Professor
Ritchie said ("Philosophical Studies," page 24)--
"It is a mistake, which has constantly been made in the
past by those who are anxious for the spiritual interests
of man, to interfere with the changes which are going on
in scientific conceptions. Such interference has always
ended in the defeat of the supporters of the
quasi-scientific doctrines which the growing science of
the time has discarded. Theology interfered with Galileo,
and gained nothing in the end by its interference.
Astronomy, geology, biology, anthropology, historical
criticism, have at different periods raised alarm in the
minds of those who dread a materialistic view of man's
nature; and with the very best intentions they have tried
to fight the supposed enemy on his own ground, eagerly
welcoming, for instance, every sign of disagreement
between Darwinians and Lamarckians, or every dispute
between different schools of historical critics, as if
the spiritual well-being of mankind were bound up with
the scientific beliefs of the seventeenth, or even
earlier, century, as if _e.g._ it made all the difference
in man's spiritual nature whether he was made directly
out of inorganic dust or slowly ascended from lower
organic forms. These are questions that must be settled
by specialists. On the other hand, philosophic criticism
is in place when the scientific specialist begins to
dogmatize about the universe as a whole, when he speaks
for example as if an accurate narrative of the various
steps by which the lower forms of life have passed into
the higher was a sufficient explanation to us of the
mystery of existence."
Let it be understood, therefore, that science is one thing, and
philosophy another: that science most properly concerns itself with
matter and motion, and reduces phenomena, as far as it can, to
mechanism. The more successfully it does that, the more it fulfils its
end and aim; but when, on the strength of that achievement, it seeks to
blossom into a philosophy, when it endeavours to conclude that its scope
is complete and all-inclusive, that nothing exists in the universe but
mechanism, and that the aspect of things from a scientific point of view
is their only aspect,--then it is becoming narrow and bigoted and
deserving of rebuke. Such rebuke it received from Huxley, such rebuke it
will always receive from scientific men who realize properly the
magnitude of existence and the vast potentialities of the universe.
Our opportunities of exploration are good as far as they go, but they
are not extensive; we live as it were in the mortar of one of the stones
of St. Paul's Cathedral; and yet so assiduously have we cultivated our
faculties that we can trace something of the outline of the whole design
and have begun to realize the plan of the building--a surprising feat
for insects of limited faculty. And--continuing the parable--two schools
of thought have arisen: one saying that it was conceived in the mind of
an architect and designed and built wholly by him, the other saying that
it was put together stone by stone in accordance with the laws of
mechanics and physics. Both statements are true, and those that
emphasize the latter are not thereby denying the existence of
Christopher Wren, though to the unwise enthusiasts on the side of design
they may appear to be doing so. Each side is stating a truth, and
neither side is stating the whole truth. Nor should we find it easy with
all our efforts to state the whole truth exhaustively, even about such a
thing as that. Those who deny any side of truth are to that extent
unbelievers, and Huxley was righteously indignant with those
shortsighted bigots who blasphemed against that aspect of divine truth
which had been specially revealed to him. This is what he lived to
preach, and to this he was faithful to the uttermost.
Let him be thought of as a devotee of truth, and a student of the more
materialistic side of things, but never let him be thought of as a
philosophical materialist or as one who abounded in cheap negations.
The objection which it is necessary to express concerning Materialism as
a complete system is based not on its assertions but on its negations.
In so far as it makes positive assertions, embodying the result of
scientific discovery and even of scientific speculation based thereupon,
there is no fault to find with it; but when, on the strength of that, it
sets up to be a philosophy of the universe--all inclusive, therefore,
and shutting out a number of truths otherwise perceived, or which appeal
to other faculties, or which are equally true and are not really
contradictory of legitimately materialistic statements--then it is that
its insufficiency and narrowness have to be displayed. As Professor
Ritchie said:--"The 'legitimate materialism of the sciences' simply
means temporary and convenient abstraction from the cognitive conditions
under which there are 'facts' or 'objects' for us at all; it is
'dogmatic materialism' which is metaphysics of the bad sort."
It will be probably instructive, and it may be sufficient, if I show
that two great leaders in scientific thought (one the greatest of all
men of science who have yet lived), though well aware of much that
could be said positively on the materialistic side, and very willing to
admit or even to extend the province of science or exact knowledge to
the uttermost, yet were very far from being philosophic materialists or
from imagining that other modes of regarding the universe were thereby
excluded.
Great leaders of thought, in fact, are not accustomed to take a narrow
view of existence, or to suppose that one mode of regarding it, or one
set of formulæ expressing it, can possibly be sufficient and complete.
Even a sheet of paper has two sides: a terrestrial globe presents
different aspects from different points of view; a crystal has a variety
of facets; and the totality of existence is not likely to be more simple
than any of these--is not likely to be readily expressible in any form
of words, or to be thoroughly conceivable by any human mind.
It may be well to remember that Sir Isaac Newton was a Theist of the
most pronounced and thorough conviction, although he had a great deal to
do with the reduction of the major Cosmos to mechanics, _i.e._, with its
explanation by the elaborated machinery of simple forces; and he
conceived it possible that, in the progress of science, this process of
reduction to mechanics would continue till it embraced nearly all the
phenomena of nature. (See extract below.) That, indeed, has been the
effort of science ever since, and therein lies the legitimate basis for
materialistic statements, though not for a materialistic philosophy.
The following sound remarks concerning Newton are taken from Huxley's
"Hume," p. 246:--
"Newton demonstrated all the host of heaven to be but the
elements of a vast mechanism, regulated by the same laws
as those which express the falling of a stone to the
ground. There is a passage in the preface to the first
edition of the 'Principia' which shows that Newton was
penetrated, as completely as Descartes, with the belief
that all the phenomena of nature are expressible in terms
of matter and motion:--
"'Would that the rest of the phenomena of nature could be
deduced by a like kind of reasoning from mechanical
principles. For many circumstances lead me to suspect
that all these phenomena may depend upon certain forces,
in virtue of which the particles of bodies, by causes not
yet known, are either mutually impelled against one
another, and cohere into regular figures, or repel and
recede from one another; which forces being unknown,
philosophers have as yet explored nature in vain. But I
hope that, either by this method of philosophizing, or by
some other and better, the principles here laid down may
throw some light upon the matter.'"
Here is a full-blown anticipation of an intelligible exposition of the
Universe in terms of matter and force--the substantial basis of what
smaller men call materialism and develop into what they consider to be a
materialistic philosophy. But there is no necessity for any such scheme;
and Professor Huxley himself, who is commonly spoken of by half-informed
people as if he were a philosophic materialist, was really nothing of
the kind; for although, like Newton, fully imbued with the mechanical
doctrine, and of course far better informed concerning the biological
departments of nature, and the discoveries which have in the last
century been made,--and though he rightly regarded it as his mission to
make the scientific point of view clear to his benighted contemporaries,
and was full of enthusiasm for the facts on which materialists take
their stand,--he saw clearly that these alone were insufficient for a
philosophy. The following extracts from the Hume volume will show that
he entirely repudiated materialism as a satisfactory or complete
philosophical system, and that he was especially severe on gratuitous
denials applied to provinces beyond our scope:--
"While it is the summit of human wisdom to learn the
limit of our faculties, it may be wise to recollect that
we have no more right to make denials, than to put forth
affirmatives, about what lies beyond that limit. Whether
either mind or matter has a 'substance' or not, is a
problem which we are incompetent to discuss: and it is
just as likely that the common notions upon the subject
should be correct as any others.... 'The same principles
which, at first view, lead to scepticism, pursued to a
certain point, bring men back to common sense'" (p. 282).
"Moreover, the ultimate forms of existence which we
distinguish in our little speck of the universe are,
possibly, only two out of infinite varieties of
existence, not only analogous to matter and analogous to
mind, but of kinds which we are not competent so much as
to conceive,--in the midst of which, indeed, we might be
set down, with no more notion of what was about us, than
the worm in a flower-pot, on a London balcony, has of the
life of the great city" (p. 286).
And again on pp. 251 and 279:--
"It is worth any amount of trouble to ... know by one's
own knowledge the great truth ... that the honest and
rigorous following up of the argument which leads us to
'materialism' inevitably carries us beyond it."
"To sum up. If the materialist affirms that the universe
and all its phenomena are resolvable into matter and
motion, Berkeley replies, True; but what you call matter
and motion are known to us only as forms of
consciousness; their being is to be conceived or known;
and the existence of a state of consciousness apart from
a thinking mind is a contradiction in terms.
"I conceive that this reasoning is irrefragable. And,
therefore, if I were obliged to choose between absolute
materialism and absolute idealism, I should feel
compelled to accept the latter alternative."
Let the jubilant but uninstructed and comparatively ignorant amateur
materialist therefore beware, and bethink himself twice or even thrice
before he conceives that he understands the universe and is competent to
pour scorn upon the intuitions and perceptions of great men in what may
be to him alien regions of thought and experience.
Let him explain, if he can, what he means by his own identity, or the
identity of any thinking or living being, which at different times
consists of a totally different set of material particles. Something
there clearly is which confers personal identity and constitutes an
individual: it is a property characteristic of every form of life, even
the humblest; but it is not yet explained or understood, and it is no
answer to assert gratuitously that there is some fundamental substance
or material basis on which that identity depends, any more than it is
an explanation to say that it depends upon a soul. These are all forms
of words. As Hume says, quoted by Huxley with approval, in the work
already cited, p. 194:--
"It is impossible to attach any definite meaning to the
word 'substance,' when employed for the hypothetical
substratum of soul and matter.... If it be said that our
personal identity requires the assumption of a substance
which remains the same while the accidents of perception
shift and change, the question arises what is meant by
personal identity?... A plant or an animal, in the course
of its existence, from the condition of an egg or seed to
the end of life, remains the same neither in form, nor in
structure, nor in the matter of which it is composed:
every attribute it possesses is constantly changing, and
yet we say that it is always one and the same individual"
(p. 194).
And in his own preface to the Hume volume Huxley expresses himself
forcibly thus--equally antagonistic as was his wont to both ostensible
friend and ostensible foe, as soon as they got off what he considered
the straight path:--
"That which it may be well for us not to forget is, that
the first-recorded judicial murder of a scientific
thinker [Socrates] was compassed and effected, not by a
despot, nor by priests, but was brought about by eloquent
demagogues.... Clear knowledge of what one does not know
is just as important as knowing what one does know....
"The development of exact natural knowledge in all its
vast range, from physics to history and criticism, is the
consequence of the working out, in this province, of the
resolution to 'take nothing for truth without clear
knowledge that it is such'; to consider all beliefs open
to criticism; to regard the value of authority as neither
greater nor less, than as much as it can prove itself to
be worth. The modern spirit is not the spirit 'which
always denies,' delighting only in destruction; still
less is it that which builds castles in the air rather
than not construct; it is that spirit which works and
will work 'without haste and without rest,' gathering
harvest after harvest of truth into its barns, and
devouring error with unquenchable fire" (p. viii).
The harvesting of truth is a fairly safe operation, for if some
falsehood be inadvertently harvested along with the grain we may hope
that, having a less robust and hardy nature, it will before long be
detected by its decaying odour; but the rooting up and devouring of
error with unquenchable fire is a more dangerous enterprise, inasmuch as
flames are apt to spread beyond our control; and the lack of
infallibility in the selection of error may to future generations become
painfully apparent.
The phrase represents a good healthy energetic mood however, and in a
world liable to become overgrown with weeds and choked with refuse, the
cleansing work of a firebrand may from time to time be a necessity, in
order that the free wind of heaven and the sunlight may once more reach
the fertile soil.
But it is unfair to think of Huxley even when young as a firebrand,
though it is true that he was to some extent a man of war, and though
the fierce and consuming mood is rather more prominent in his early
writings than in his later work.
A fighting attitude was inevitable forty years ago, because then the
truths of biology were being received with hostility, and the free
science and philosophy of a later time seemed likely to have a poor
chance of life. But the world has changed or is changing now, the
wholesome influences of fire have done their work, and it would be a
rather barbarous anachronism to apply the same agency among the young
green shoots of healthy learning which are springing up in the cleared
ground.
OLIVER LODGE.
1906.
* * * * *
Among the earlier published works of T. H. Huxley (1825-1895), and of
the essays contained in this volume: "The Darwinian Hypothesis" first
appeared in the _Times_, Dec. 26, 1859; "On the Educational Value of the
Natural History Sciences" (Address given at St. Martin's Hall), was
published in 1854; "Time and Life" (_Macmillan's Magazine_), Dec. 1859;
"The Origin of Species" (_Westminster Review_), April 1860; "A Lobster:
or, The Study of Zoology," 1861. "Geological Contemporaneity and
Persistent Types of Life" (Address to Geological Society), 1862, was
re-published in "Lay Sermons," vol. viii.; "Six Lectures to Working Men
on the Phenomena of Organic Nature," 1863, in "Collected Essays," vol.
vii. "Evidence as to Man's Place in Nature," 1863. Of his other works,
the translation by Huxley and Busk of "Kölliker's Manual of Human
Histology," appeared in 1853. "Lectures on the Elements of Comparative
Anatomy," "Elementary Atlas of Comparative Osteology"; two Science
Lectures, "The Circulation of the Blood" and "Corals and Coral Reefs,"
and "Lessons in Elementary Physiology," in 1866. "Introduction to the
Classification of Animals," 1869. "Lay Sermons, Essays, and Reviews,"
1870. "Critiques and Addresses," 1873. "On Yeast: A Lecture," 1872. "A
Manual of the Anatomy of Vertebrated Animals," 1871. "Manual of the
Anatomy of Invertebrated Animals," 1877. "American Addresses," 1877.
"Physiography," 1877. "Hume" in "English Men of Letters," 1878. "The
Crayfish: an Introduction to the Study of Zoology," 1880. "Science and
Culture, and other Essays," 1881. "Essays upon some Controverted
Questions," 1892. "Evolution and Ethics" (the Romanes Lecture), 1893.
Huxley also assisted in editing the series of Science Primers published
by Messrs. Macmillan, and contributed the introductory volume himself.
The "Collected Essays," in nine vols., containing all that he cared to
preserve, 1893. "The Scientific Memoirs of T. H. Huxley," edited by
Professor Michael Foster and Professor E. Ray Lankester, in five vols.,
1898-1903. His "Life and Letters," edited by his son, Leonard Huxley,
was published in 1900.
[Illustration: _Skeletons of the_
GIBBON. ORANG. CHIMPANZEE. GORILLA. MAN.
_Photographically reduced from Diagrams of the natural size_ (_except
that of the Gibbon, which was twice as large as nature_), _drawn by Mr.
Waterhouse Hawkins from specimens in the Museum of the Royal College of
Surgeons_.]
HUXLEY'S ESSAYS
I
ON THE NATURAL HISTORY OF THE
MAN-LIKE APES.
Ancient traditions, when tested by the severe processes of modern
investigation, commonly enough fade away into mere dreams: but it is
singular how often the dream turns out to have been a half-waking one,
presaging a reality. Ovid foreshadowed the discoveries of the geologist:
the Atlantis was an imagination, but Columbus found a western world: and
though the quaint forms of Centaurs and Satyrs have an existence only in
the realms of art, creatures approaching man more nearly than they in
essential structure, and yet as thoroughly brutal as the goat's or
horse's half of the mythical compound, are now not only known, but
notorious.
I have not met with any notice of one of these MAN-LIKE APES of earlier
date than that contained in Pigafetta's "Description of the Kingdom of
Congo,"[1] drawn up from the notes of a Portuguese sailor, Eduardo
Lopez, and published in 1598. The tenth chapter of this work is entitled
"De Animalibus quæ in hac provincia reperiuntur," and contains a brief
passage to the effect that "in the Songan country, on the banks of the
Zaire, there are multitudes of apes, which afford great delight to the
nobles by imitating human gestures." As this might apply to almost any
kind of apes, I should have thought little of it, had not the brothers
De Bry, whose engravings illustrate the work, thought fit, in their
eleventh "Argumentum," to figure two of these "Simiæ magnatum deliciæ."
So much of the plate as contains these apes is faithfully copied in the
woodcut (Fig. 1), and it will be observed that they are tail-less,
long-armed, and large-eared; and about the size of Chimpanzees. It may
be that these apes are as much figments of the imagination of the
ingenious brothers as the winged, two-legged, crocodile-headed dragon
which adorns the same plate; or, on the other hand, it may be that the
artists have constructed their drawings from some essentially faithful
description of a Gorilla or a Chimpanzee. And, in either case, though
these figures are worth a passing notice, the oldest trustworthy and
definite accounts of any animal of this kind date from the 17th
century, and are due to an Englishman.
[Illustration: FIG. 1.--Simiæ magnatum deliciæ.--De Bry, 1598.]
The first edition of that most amusing old book, "Purchas his
Pilgrimage," was published in 1613, and therein are to be found many
references to the statements of one whom Purchas terms "Andrew Battell
(my neere neighbour, dwelling at Leigh in Essex) who served under Manuel
Silvera Perera, Governor under the King of Spaine, at his city of Saint
Paul, and with him went farre into the countrey of Angola"; and again,
"my friend, Andrew Battle, who lived in the kingdom of Congo many
yeares," and who, "upon some quarell betwixt the Portugals (among whom
he was a sergeant of a band) and him, lived eight or nine moneths in the
woodes." From this weather-beaten old soldier, Purchas was amazed to
hear "of a kinde of Great Apes, if they might so bee termed, of the
height of a man, but twice as bigge in feature of their limmes, with
strength proportionable, hairie all over, otherwise altogether like men
and women in their whole bodily shape.[2] They lived on such wilde
fruits as the trees and woods yielded, and in the night time lodged on
the trees."
This extract is, however, less detailed and clear in its statements than
a passage in the third chapter of the second part of another
work--"Purchas his Pilgrimes," published in 1625, by the same
author--which has been often, though hardly ever quite rightly, cited.
The chapter is entitled, "The strange adventures of Andrew Battell, of
Leigh in Essex, sent by the Portugals prisoner to Angola, who lived
there and in the adjioining regions neere eighteene yeeres." And the
sixth section of this chapter is headed--"Of the Provinces of Bongo,
Calongo, Mayombe, Manikesocke, Motimbas: of the Ape Monster Pongo, their
hunting: Idolatries; and divers other observations."
"This province (Calongo) toward the east bordereth upon
Bongo, and toward the north upon Mayombe, which is nineteen
leagues from Longo along the coast.
"This province of Mayombe is all woods and groves, so
overgrowne that a man may travaile twentie days in the shadow
without any sunne or heat. Here is no kind of corne nor
graine, so that the people liveth onely upon plantanes and
roots of sundrie sorts, very good; and nuts; nor any kinde of
tame cattell, nor hens.
"But they have great store of elephant's flesh, which they
greatly esteeme, and many kinds of wild beasts; and great
store of fish. Here is a great sandy bay, two leagues to the
northward of Cape Negro,[3] which is the port of Mayombe.
Sometimes the Portugals lade log-wood in this bay. Here is a
great river, called Banna: in the winter it hath no barre,
because the generall winds cause a great sea. But when the
sunne hath his south declination, then a boat may goe in; for
then it is smooth because of the raine. This river is very
great, and hath many ilands and people dwelling in them. The
woods are so covered with baboones, monkies, apes and
parrots, that it will feare any man to travaile in them
alone. Here are also two kinds of monsters, which are common
in these woods, and very dangerous.
"The greatest of these two monsters is called Pongo in their
language, and the lesser is called Engeco. This Pongo is in
all proportion like a man; but that he is more like a giant
in stature than a man; for he is very tall, and hath a man's
face, hollow-eyed, with long haire upon his browes. His face
and eares are without haire, and his hands also. His bodie is
full of haire, but not very thicke; and it is of a dunnish
colour.
"He differeth not from a man but in his legs; for they have
no calfe. Hee goeth alwaies upon his legs, and carrieth his
hands clasped in the nape of his necke when he goeth upon the
ground. They sleepe in the trees, and build shelters for the
raine. They feed upon fruit that they find in the woods, and
upon nuts, for they eate no kind of flesh. They cannot
speake, and have no understanding more than a beast. The
people of the countrie, when they travaile in the woods make
fires where they sleepe in the night; and in the morning when
they are gone, the Pongoes will come and sit about the fire
till it goeth out; for they have no understanding to lay the
wood together. They goe many together and kill many negroes
that travaile in the woods. Many times they fall upon the
elephants which come to feed where they be, and so beate them
with their clubbed fists, and pieces of wood, that they will
runne roaring away from them. Those Pongoes are never taken
alive because they are so strong, that ten men cannot hold
one of them; but yet they take many of their young ones with
poisoned arrowes.
"The young Pongo hangeth on his mother's belly with his hands
fast clasped about her, so that when the countrie people kill
any of the females they take the young one, which hangeth
fast upon his mother.
"When they die among themselves, they cover the dead with
great heaps of boughs and wood, which is commonly found in
the forest."[4]
It does not appear difficult to identify the exact region of which
Battell speaks. Longo is doubtless the name of the place usually spelled
Loango on our maps. Mayombe still lies some nineteen leagues northward
from Loango, along the coast; and Cilongo or Kilonga, Manikesocke, and
Motimbas are yet registered by geographers. The Cape Negro of Battell,
however, cannot be the modern Cape Negro in 16° S., since Loango itself
is in 4° S. latitude. On the other hand, the "great river called Banna"
corresponds very well with the "Camma" and "Fernand Vas," of modern
geographers, which form a great delta on this part of the African coast.
Now this "Camma" country is situated about a degree and a-half south of
the Equator, while a few miles to the north of the line lies the Gaboon,
and a degree or so north of that, the Money River--both well known to
modern naturalists as localities where the largest of man-like Apes has
been obtained. Moreover, at the present day, the word Engeco, or
N'schego, is applied by the natives of these regions to the smaller of
the two great Apes which inhabit them; so that there can be no rational
doubt that Andrew Battell spoke of that which he knew of his own
knowledge, or, at any rate, by immediate report from the natives of
Western Africa. The "Engeco," however, is that "other monster" whose
nature Battell "forgot to relate," while the name "Pongo"--applied to
the animal whose characters and habits are so fully and carefully
described--seems to have died out, at least in its primitive form and
signification. Indeed, there is evidence that not only in Battell's
time, but up to a very recent date, it was used in a totally different
sense from that in which he employs it.
For example, the second chapter of Purchas' work, which I have just
quoted, contains "A Description and Historicall Declaration of the
Golden Kingdom of Guinea, &c. &c. Translated from the Dutch, and
compared also with the Latin," wherein it is stated (p. 986) that--
"The River Gaboon lyeth about fifteen miles northward
from Rio de Angra, and eight miles northward from Cape de
Lope Gonsalvez (Cape Lopez), and is right under the
Equinoctial line, about fifteene miles from St. Thomas,
and is a great land, well and easily to be knowne. At the
mouth of the river there lieth a sand, three or foure
fathoms deepe, whereon it beateth mightily with the
streame which runneth out of the river into the sea. This
river, in the mouth thereof, is at least four miles
broad; but when you are about the Iland called _Pongo_,
it is not above two miles broad.... On both sides the
river there standeth many trees.... The Iland called
_Pongo_, which hath a monstrous high hill."
The French naval officers, whose letters are appended to the late M.
Isidore Geoff. Saint Hilaire's excellent essay on the Gorilla,[5] note
in similar terms the width of the Gaboon, the trees that line its banks
down to the water's edge, and the strong current that sets out of it.
They describe two islands in its estuary;--one low, called Perroquet;
the other high, presenting three conical hills, called Coniquet; and one
of them, M. Franquet, expressly states that, formerly, the Chief of
Coniquet was called _Meni-Pongo_, meaning thereby Lord of _Pongo_; and
that the _N'Pongues_ (as, in agreement with Dr. Savage, he affirms the
natives call themselves) term the estuary of the Gaboon itself
_N'Pongo_.
It is so easy, in dealing with savages, to misunderstand their
applications of words to things, that one is at first inclined to
suspect Battell of having confounded the name of this region, where his
"greater monster" still abounds, with the name of the animal itself. But
he is so right about other matters (including the name of the "lesser
monster") that one is loth to suspect the old traveller of error; and,
on the other hand, we shall find that a voyager of a hundred years'
later date speaks of the name "Boggoe," as applied to a great Ape, by
the inhabitants of quite another part of Africa--Sierra Leone.
[Illustration: _Homo Sylvestris. Orang Outang._
FIG. 2.--The Orang of Tulpius, 1641.]
But I must leave this question to be settled by philologers and
travellers; and I should hardly have dwelt so long upon it except for
the curious part played by this word "_Pongo_" in the later history of
the man-like Apes.
The generation which succeeded Battell saw the first of the man-like
Apes which was ever brought to Europe, or, at any rate, whose visit
found a historian. In the third book of Tulpius' "Observationes Medicæ,"
published in 1641, the 56th chapter or section is devoted to what he
calls _Satyrus indicus_, "called by the Indians Orang-autang, or
Man-of-the-Woods, and by the Africans Quoias Morrou." He gives a very
good figure, evidently from the life, of the specimen of this animal,
"nostra memoria ex Angolâ delatum," presented to Frederick Henry Prince
of Orange. Tulpius says it was as big as a child of three years old, and
as stout as one of six years: and that its back was covered with black
hair. It is plainly a young Chimpanzee.
In the meanwhile, the existence of other, Asiatic, man-like Apes became
known, but at first in a very mythical fashion. Thus Bontius (1658)
gives an altogether fabulous and ridiculous account and figure of an
animal which he calls "Orang-outang"; and though he says, "vidi Ego
cujus effigiem hic exhibeo," the said effigies (see Fig. 6 for Hoppius'
copy of it) is nothing but a very hairy woman of rather comely aspect,
and with proportions and feet wholly human. The judicious English
anatomist, Tyson, was justified in saying of this description by
Bontius, "I confess I do mistrust the whole representation."
It is to the last mentioned writer, and his coadjutor Cowper, that we
owe the first account of a man-like ape which has any pretensions to
scientific accuracy and completeness. The treatise entitled,
"_Orang-outang, sive Homo Sylvestris_; or the Anatomy of a Pygmie
compared with that of a _Monkey_, an _Ape_, and a _Man_," published by
the Royal Society in 1699, is, indeed, a work of remarkable merit, and
has, in some respects, served as a model to subsequent inquirers. This
"Pygmie," Tyson tells us, "was brought from Angola, in Africa; but was
first taken a great deal higher up the country"; its hair "was of a
coal-black colour, and strait," and "when it went as a quadruped on all
four, 'twas awkwardly; not placing the palm of the hand flat to the
ground, but it walk'd upon its knuckles, as I observed it to do when
weak and had not strength enough to support its body."--"From the top of
the head to the heel of the foot, in a strait line, it measured
twenty-six inches."
[Illustration: FIGS. 3 and 4.--The "Pygmie" reduced from Tyson's figures
1 and 2, 1699.]
These characters, even without Tyson's good figures (Figs. 3 and 4),
would have been sufficient to prove his "Pygmie" to be a young
Chimpanzee. But the opportunity of examining the skeleton of the very
animal Tyson anatomised having most unexpectedly presented itself to me,
I am able to bear independent testimony to its being a veritable
_Troglodytes niger_,[6] though still very young. Although fully
appreciating the resemblances between his Pygmie and Man, Tyson by no
means overlooked the differences between the two, and he concludes his
memoir by summing up first, the points in which "the Ourang-outang or
Pygmie more resembled a Man than Apes and Monkeys do," under forty-seven
distinct heads; and then giving, in thirty-four similar brief
paragraphs, the respects in which "the Ourang-outang or Pygmie differ'd
from a Man and resembled more the Ape and Monkey kind."
After a careful survey of the literature of the subject extant in his
time, our author arrives at the conclusion that his "Pygmie" is
identical neither with the Orangs of Tulpius and Bontius, nor with the
Quoias Morrou of Dapper (or rather of Tulpius), the Barris of d'Arcos,
nor with the Pongo of Battell; but that it is a species of ape probably
identical with the Pygmies of the Ancients, and, says Tyson, though it
"does so much resemble _a Man_ in many of its parts, more than any of
the ape kind, or any other animal in the world, that I know of: yet by
no means do I look upon it as the product of a _mixt_ generation--'tis a
_Brute-Animal sui generis_, and a particular _species of Ape_."
The name of "Chimpanzee," by which one of the African Apes is now so
well known, appears to have come into use in the first half of the
eighteenth century, but the only important addition made, in that
period, to our acquaintance with the man-like apes of Africa is
contained in "A New Voyage to Guinea," by William Smith, which bears the
date 1744.
In describing the animals of Sierra Leone, p. 51, this writer says:--
"I shall next describe a strange sort of animal, called
by the white men in this country Mandrill,[7] but why it
is so called I know not, nor did I ever hear the name
before, neither can those who call them so tell, except
it be for their near resemblance of a human creature,
though nothing at all like an Ape. Their bodies, when
full grown, are as big in circumference as a middle-sized
man's--their legs much shorter, and their feet larger;
their arms and hands in proportion. The head is
monstrously big, and the face broad and flat, without any
other hair but the eyebrows; the nose very small, the
mouth wide, and the lips thin. The face, which is covered
by a white skin, is monstrously ugly, being all over
wrinkled as with old age; the teeth broad and yellow; the
hands have no more hair than the face, but the same white
skin, though all the rest of the body is covered with
long black hair, like a bear. They never go upon all
fours, like apes; but cry, when vexed or teased, just
like children....
[Illustration: FIG. 5.--Facsimile of William Smith's figure of the
"Mandrill," 1744.]
"When I was at Sherbro, one Mr. Cummerbus, whom I shall
have occasion hereafter to mention, made me a present of
one of these strange animals, which are called by the
natives Boggoe: it was a she-cub, of six months' age, but
even then larger than a Baboon. I gave it in charge to
one of the slaves, who knew how to feed and nurse it,
being a very tender sort of animal; but whenever I went
off the deck the sailors began to teaze it--some loved to
see its tears and hear it cry; others hated its
snotty-nose; one who hurt it, being checked by the negro
that took care of it, told the slave he was very fond of
his country-woman, and asked him if he should not like
her for a wife? To which the slave very readily replied,
'No, this no my wife; this a white woman--this fit wife
for you.' This unlucky wit of the negro's, I fancy,
hastened its death, for next morning it was found dead
under the windlass."
William Smith's "Mandrill," or "Boggoe," as his description and figure
testify, was, without doubt, a Chimpanzee.
[Illustration: FIG. 6.--The Anthropomorpha of Linnæus.]
Linnæus knew nothing, of his own observation, of the man-like Apes of
either Africa or Asia, but a dissertation by his pupil Hoppius in the
"Amoenitates Academicæ" (VI. "Anthropomorpha") may be regarded as
embodying his views respecting these animals.
The dissertation is illustrated by a plate, of which the accompanying
woodcut, Fig. 6, is a reduced copy. The figures are entitled (from left
to right) 1. _Troglodyta Bontii_; 2. _Lucifer Aldrovandi_; 3. _Satyrus
Tulpii_; 4. _Pygmæus Edwardi_. The first is a bad copy of Bontius'
fictitious "Ourang-outang," in whose existence, however, Linnæus appears
to have fully believed; for in the standard edition of the "Systema
Naturæ," it is enumerated as a second species of Homo; "H. nocturnus."
_Lucifer Aldrovandi_ is a copy of a figure in Aldrovandus, "De
Quadrupedibus digitatis viviparis," Lib. 2, p. 249 (1645), entitled
"Cercopithecus formæ raræ _Barbilius_ vocatus et originem a china
ducebat." Hoppius is of opinion that this may be one of that cat-tailed
people, of whom Nicolaus Köping affirms that they eat a boat's crew,
"gubernator navis" and all! In the "Systema Naturæ" Linnæus calls it in
a note, _Homo caudatus_, and seems inclined to regard it as a third
species of man. According to Temminck, _Satyrus Tulpii_ is a copy of the
figure of a Chimpanzee published by Scotin in 1738, which I have not
seen. It is the _Satyrus indicus_ of the "Systema Naturæ," and is
regarded by Linnæus as possibly a distinct species from _Satyrus
sylvestris_. The last, named _Pygmæus Edwardi_, is copied from the
figure of a young "Man of the Woods," or true Orang-Utan, given in
Edwards "Gleanings of Natural History" (1758).
Buffon was more fortunate than his great rival. Not only had he the rare
opportunity of examining a young Chimpanzee in the living state, but he
became possessed of an adult Asiatic man-like Ape--the first and the
last adult specimen of any of these animals brought to Europe for many
years. With the valuable assistance of Daubenton, Buffon gave an
excellent description of this creature, which, from its singular
proportions, he termed the long-armed Ape, or Gibbon. It is the modern
_Hylobates lar_.
Thus when, in 1766, Buffon wrote the fourteenth volume of his great
work, he was personally familiar with the young of one kind of African
man-like Ape, and with the adult of an Asiatic species--while the
Orang-Utan and the Mandrill of Smith were known to him by report.
Furthermore, the Abbé Prevost had translated a good deal of Purchas'
Pilgrims into French, in his "Histoire générale des Voyages" (1748), and
there Buffon found a version of Andrew Battell's account of the Pongo
and the Engeco. All these data Buffon attempts to weld together into
harmony in his chapter entitled "Les Orang-outangs ou le Pongo et le
Jocko." To this title the following note is appended:--
"Orang-outang nom de cet animal aux Indes orientales:
Pongo nom de cet animal à Lowando Province de Congo.
"Jocko, Enjocko, nom de cet animal à Congo que nous avons
adopté. _En_ est l'article que nous avons retranché."
Thus it was that Andrew Battell's "Engeco" became metamorphosed into
"Jocko," and, in the latter shape, was spread all over the world, in
consequence of the extensive popularity of Buffon's works. The Abbé
Prevost and Buffon between them, however, did a good deal more
disfigurement to Battell's sober account than "cutting off an article."
Thus Battell's statement that the Pongos "cannot speake, and have no
understanding more than a beast," is rendered by Buffon "qu'il ne peut
parler _quoiqu'il ait plus d'entendement que les autres animaux_"; and
again, Purchas' affirmation, "He told me in conference with him, that
one of these Pongos tooke a negro boy of his which lived a moneth with
them," stands in the French version, "un pongo lui enleva un petit negre
qui passa un _an_ entier dans la societé de ces animaux."
After quoting the account of the great Pongo, Buffon justly remarks,
that all the "Jockos" and "Orangs" hitherto brought to Europe were
young; and he suggests that, in their adult condition, they might be as
big as the Pongo or "great Orang"; so that, provisionally, he regarded
the Jockos, Orangs, and Pongos as all of one species. And perhaps this
was as much as the state of knowledge at the time warranted. But how it
came about that Buffon failed to perceive the similarity of Smith's
"Mandrill" to his own "Jocko," and confounded the former with so totally
different a creature as the blue-faced Baboon, is not so easily
intelligible.
Twenty years later Buffon changed his opinion,[8] and expressed his
belief that the Orangs constituted a genus with two species,--a large
one, the Pongo of Battell, and a small one, the Jocko: that the small
one (Jocko) is the East Indian Orang; and that the young animals from
Africa, observed by himself and Tulpius, are simply young Pongos.
In the meanwhile, the Dutch naturalist, Vosmaer, gave, in 1778, a very
good account and figure of a young Orang, brought alive to Holland, and
his countryman, the famous anatomist, Peter Camper, published (1779) an
essay on the Orang-Utan of similar value to that of Tyson on the
Chimpanzee. He dissected several females and a male, all of which, from
the state of their skeleton and their dentition, he justly supposes to
have been young. However, judging by the analogy of man, he concludes
that they could not have exceeded four feet in height in the adult
condition. Furthermore, he is very clear as to the specific distinctness
of the true East Indian Orang.
"The Orang," says he, "differs not only from the Pigmy of Tyson and from
the Orang of Tulpius by its peculiar colour and its long toes, but also
by its whole external form. Its arms, its hands, and its feet are
longer, while the thumbs, on the contrary, are much shorter, and the
great toes much smaller in proportion."[9] And again, "The true Orang,
that is to say, that of Asia, that of Borneo, is consequently not the
Pithecus, or tail-less Ape, which the Greeks, and especially Galen, have
described. It is neither the Pongo nor the Jocko, nor the Orang of
Tulpius, nor the Pigmy of Tyson,--_it is an animal of a peculiar
species_, as I shall prove in the clearest manner by the organs of voice
and the skeleton in the following chapters" (l. c. p. 64).
A few years later, M. Radermacher, who held a high office in the
Government of the Dutch dominions in India, and was an active member of
the Batavian Society of Arts and Sciences, published, in the second part
of the Transactions of that Society,[10] a Description of the Island of
Borneo, which was written between the years 1779 and 1781, and, among
much other interesting matter, contains some notes upon the Orang. The
small sort of Orang-Utan, viz. that of Vosmaer and of Edwards, he says,
is found only in Borneo, and chiefly about Banjermassing, Mampauwa, and
Landak. Of these he had seen some fifty during his residence in the
Indies; but none exceeded 2-1/2 feet in length. The larger sort, often
regarded as chimæra, continues Radermacher, would, perhaps long have
remained so, had it not been for the exertions of the Resident at
Rembang, M. Palm, who, on returning from Landak towards Pontiana, shot
one, and forwarded it to Batavia in spirit, for transmission to Europe.
Palm's letter describing the capture runs thus:--"Herewith I send your
Excellency, contrary to all expectation (since long ago I offered more
than a hundred ducats to the natives for an Orang-Utan of four or five
feet high) an Orang which I heard of this morning about eight o'clock.
For a long time we did our best to take the frightful beast alive in the
dense forest about half way to Landak. We forgot even to eat, so anxious
were we not to let him escape; but it was necessary to take care he did
not revenge himself, as he kept continually breaking off heavy pieces of
wood and green branches, and dashing them at us. This game lasted till
four o'clock in the afternoon, when we determined to shoot him; in which
I succeeded very well, and indeed better than I ever shot from a boat
before; for the bullet went just into the side of his chest, so that he
was not much damaged. We got him into the prow still living, and bound
him fast, and next morning he died of his wounds. All Pontiana came on
board to see him when we arrived." Palm gives his height from the head
to the heel as 49 inches.
A very intelligent German officer, Baron Von Wurmb, who at this time
held a post in the Dutch East India service, and was Secretary of the
Batavian Society, studied this animal, and his careful description of
it, entitled "Beschrijving van der Groote Borneosche Orang-outang of de
Oost-Indische Pongo," is contained in the same volume of the Batavian
Society's Transactions. After Von Wurmb had drawn up his description he
states, in a letter dated Batavia, Feb. 18, 1781,[11] that the specimen
was sent to Europe in brandy to be placed in the collection of the
Prince of Orange; "unfortunately," he continues, "we hear that the ship
has been wrecked." Von Wurmb died in the course of the year 1781, the
letter in which this passage occurs being the last he wrote; but in his
posthumous papers, published in the fourth part of the Transactions of
the Batavian Society, there is a brief description, with measurements,
of a female Pongo four feet high.
[Illustration: FIG. 7.--The Pongo Skull, sent by Radermacher to
Camper, after Camper's original sketches, as reproduced by Lucæ.]
Did either of these original specimens, on which Von Wurmb's
descriptions are based, ever reach Europe? It is commonly supposed that
they did; but I doubt the fact. For, appended to the memoir "De
l'Ourang-outang," in the collected edition of Camper's works, tome i.,
pp. 64-66, is a note by Camper himself, referring to Von Wurmb's papers,
and continuing thus:--"Heretofore, this kind of ape had never been known
in Europe. Radermacher has had the kindness to send me the skull of one
of these animals, which measured fifty-three inches, or four feet five
inches, in height. I have sent some sketches of it to M. Soemmering at
Mayence, which are better calculated, however, to give an idea of the
form than of the real size of the parts."
These sketches have been reproduced by Fischer and by Lucæ, and bear
date 1783, Soemmering having received them in 1784. Had either of Von
Wurmb's specimens reached Holland, they would hardly have been unknown
at this time to Camper, who, however, goes on to say:--"It appears that
since this, some more of these monsters have been captured, for an
entire skeleton, very badly set up, which had been sent to the Museum
of the Prince of Orange, and which I saw only on the 27th of June, 1784,
was more than four feet high. I examined this skeleton again on the 19th
December, 1785, after it had been excellently put to rights by the
ingenious Onymus."
It appears evident, then, that this skeleton, which is doubtless that
which has always gone by the name of Wurmb's Pongo, is not that of the
animal described by him, though unquestionably similar in all essential
points.
Camper proceeds to note some of the most important features of this
skeleton; promises to describe it in detail by-and-bye; and is evidently
in doubt as to the relation of this great "Pongo" to his "petit Orang."
The promised further investigations were never carried out; and so it
happened that the Pongo of Von Wurmb took its place by the side of the
Chimpanzee, Gibbon, and Orang as a fourth and colossal species of
man-like Ape. And indeed nothing could look much less like the
Chimpanzees or the Orangs, then known, than the Pongo; for all the
specimens of Chimpanzee and Orang which had been observed were small of
stature, singularly human in aspect, gentle and docile; while Wurmb's
Pongo was a monster almost twice their size, of vast strength and
fierceness, and very brutal in expression; its great projecting muzzle,
armed with strong teeth, being further disfigured by the outgrowth of
the cheeks into fleshy lobes.
Eventually, in accordance with the usual marauding habits of the
Revolutionary armies, the "Pongo" skeleton was carried away from Holland
into France, and notices of it, expressly intended to demonstrate its
entire distinctness from the Orang and its affinity with the baboons,
were given, in 1798, by Geoffroy St. Hilaire and Cuvier.
Even in Cuvier's "Tableau Elementaire," and in the first edition of his
great work, the "Regne Animal," the "Pongo" is classed as a species of
Baboon. However, so early as 1818, it appears that Cuvier saw reason to
alter this opinion, and to adopt the view suggested several years
before by Blumenbach,[12] and after him by Tilesius, that the Bornean
Pongo is simply an adult Orang. In 1824, Rudolphi demonstrated, by the
condition of the dentition, more fully and completely than had been done
by his predecessors, that the Orangs described up to that time were all
young animals, and that the skull and teeth of the adult would probably
be such as those seen in the Pongo of Wurmb. In the second edition of
the "Regne Animal" (1829), Cuvier infers, from the "proportions of all
the parts" and "the arrangements of the foramina and sutures of the
head," that the Pongo is the adult of the Orang-Utan, "at least of a
very closely allied species," and this conclusion was eventually placed
beyond all doubt by Professor Owen's Memoir published in the "Zoological
Transactions" for 1835, and by Temminck in his "Monographies de
Mammalogie." Temminck's memoir is remarkable for the completeness of the
evidence which it affords as to the modification which the form of the
Orang undergoes according to age and sex. Tiedemann first published an
account of the brain of the young Orang, while Sandifort, Müller and
Schlegel, described the muscles and the viscera of the adult, and gave
the earliest detailed and trustworthy history of the habits of the great
Indian Ape in a state of nature; and as important additions have been
made by later observers, we are at this moment better acquainted with
the adult of the Orang-Utan, than with that of any of the other greater
man-like Apes.
It is certainly the Pongo of Wurmb;[13] and it is as certainly not the
Pongo of Battell, seeing that the Orang-Utan is entirely confined to the
great Asiatic islands of Borneo and Sumatra.
And while the progress of discovery thus cleared up the history of the
Orang, it also became established that the only other man-like Apes in
the eastern world were the various species of Gibbon--Apes of smaller
stature, and therefore attracting less attention than the Orangs,
though they are spread over a much wider range of country, and are hence
more accessible to observation.
* * * * *
Although the geographical area inhabited by the "Pongo" and "Engeco" of
Battell is so much nearer to Europe than that in which the Orang and
Gibbon are found, our acquaintance with the African Apes has been of
slower growth; indeed, it is only within the last few years that the
truthful story of the old English adventurer has been rendered fully
intelligible. It was not until 1835 that the skeleton of the adult
Chimpanzee became known, by the publication of Professor Owen's
above-mentioned very excellent memoir "On the osteology of the
Chimpanzee and Orang," in the Zoological Transactions--a memoir which,
by the accuracy of its descriptions, the carefulness of its comparisons,
and the excellence of its figures, made an epoch in the history of our
knowledge of the bony framework, not only of the Chimpanzee, but of all
the anthropoid Apes.
By the investigations herein detailed, it became evident that the old
Chimpanzee acquired a size and aspect as different from those of the
young known to Tyson, to Buffon, and to Traill, as those of the old
Orang from the young Orang; and the subsequent very important researches
of Messrs. Savage and Wyman, the American missionary and anatomist, have
not only confirmed this conclusion, but have added many new details.[14]
One of the most interesting among the many valuable discoveries made by
Dr. Thomas Savage is the fact, that the natives in the Gaboon country at
the present day, apply to the Chimpanzee a name--"Enché-eko"--which is
obviously identical with the "Engeko" of Battell; a discovery which has
been confirmed by all later inquirers. Battell's "lesser monster," being
thus proved to be a veritable existence, of course a strong presumption
arose that his "greater monster," the "Pongo," would sooner or later be
discovered. And, indeed, a modern traveller, Bowdich, had, in 1819,
found strong evidence, among the natives, of the existence of a second
great Ape, called the "Ingena," "five feet high, and four across the
shoulders," the builder of a rude house, on the outside of which it
slept.
In 1847, Dr. Savage had the good fortune to make another and most
important addition to our knowledge of the man-like Apes; for, being
unexpectedly detained at the Gaboon river, he saw in the house of the
Rev. Mr. Wilson, a missionary resident there, "a skull represented by
the natives to be a monkey-like animal, remarkable for its size,
ferocity, and habits." From the contour of the skull, and the
information derived from several intelligent natives, "I was induced,"
says Dr. Savage (using the term Orang in its old general sense), "to
believe that it belonged to a new species of Orang. I expressed this
opinion to Mr. Wilson, with a desire for further investigation; and, if
possible, to decide the point by the inspection of a specimen alive or
dead." The result of the combined exertions of Messrs. Savage and Wilson
was not only the obtaining of a very full account of the habits of this
new creature, but a still more important service to science, the
enabling the excellent American anatomist already mentioned, Professor
Wyman, to describe, from ample materials, the distinctive osteological
characters of the new form. This animal was called by the natives of the
Gaboon "Engé-ena," a name obviously identical with the "Ingena" of
Bowdich; and Dr. Savage arrived at the conviction that this last
discovered of all the great Apes was the long-sought "Pongo" of Battell.
The justice of this conclusion, indeed, is beyond doubt--for not only
does the "Engé-ena" agree with Battell's "greater monster" in its hollow
eyes, its great stature and its dun or iron-grey colour, but the only
other man-like Ape which inhabits these latitudes--the Chimpanzee--is at
once identified, by its smaller size, as the "lesser monster," and is
excluded from any possibility of being the "Pongo," by the fact that it
is black and not dun, to say nothing of the important circumstance
already mentioned that it still retains the name of "Engeko," or
"Enché-eko," by which Battell knew it.
In seeking for a specific name for the "Engé-ena," however, Dr. Savage
wisely avoided the much misused "Pongo"; but finding in the ancient
Periplus of Hanno the word "Gorilla" applied to certain hairy savage
people, discovered by the Carthaginian voyager in an island on the
African coast, he attached the specific name "_Gorilla_" to his new ape,
whence arises its present well-known appellation. But Dr. Savage, more
cautious than some of his successors, by no means identifies his ape
with Hanno's "wild men." He merely says that the latter were "probably
one of the species of the Orang;" and I quite agree with M. Brullé that
there is no ground for identifying the modern "Gorilla" with that of the
Carthaginian admiral.
Since the memoir of Savage and Wyman was published, the skeleton of the
Gorilla has been investigated by Professor Owen and by the late
Professor Duvernoy, of the Jardin des Plantes, the latter having further
supplied a valuable account of the muscular system and of many of the
other soft parts; while African missionaries and travellers have
confirmed and expanded the account originally given of the habits of
this great man-like Ape, which has had the singular fortune of being the
first to be made known to the general world and the last to be
scientifically investigated.
Two centuries and a half have passed away since Battell told his stories
about the "greater" and the "lesser monsters" to Purchas, and it has
taken nearly that time to arrive at the clear result that there are four
distinct kinds of Anthropoids--in Eastern Asia, the Gibbons and the
Orangs; in Western Africa, the Chimpanzees and the Gorilla.
* * * * *
The man-like Apes, the history of whose discovery has just been
detailed, have certain characters of structure and of distribution in
common. Thus they all have the same number of teeth as man--possessing
four incisors, two canines, four false molars, and six true molars in
each jaw, or 32 teeth in all, in the adult condition; while the milk
dentition consists of 20 teeth--or four incisors, two canines, and four
molars in each jaw. They are what are called catarrhine Apes--that is,
their nostrils have a narrow partition and look downwards; and,
furthermore, their arms are always longer than their legs, the
difference being sometimes greater and sometimes less; so that if the
four were arranged in the order of the length of their arms in
proportion to that of their legs, we should have this series--Orang
(1-4/9--1), Gibbon (1-1/4--1), Gorilla (1-1/5--1), Chimpanzee
(1-1/16--1). In all, the fore-limbs are terminated by hands, provided
with longer or shorter thumbs; while the great toe of the foot, always
smaller than in Man, is far more moveable than in him and can be
opposed, like a thumb, to the rest of the foot. None of these apes have
tails, and none of them possess the cheek-pouches common among monkeys.
Finally, they are all inhabitants of the old world.
The Gibbons are the smallest, slenderest, and longest-limbed of the
man-like Apes: their arms are longer in proportion to their bodies than
those of any of the other man-like Apes, so that they can touch the
ground when erect; their hands are longer than their feet, and they are
the only Anthropoids which possess callosities like the lower monkeys.
They are variously coloured. The Orangs have arms which reach to the
ankles in the erect position of the animal; their thumbs and great toes
are very short, and their feet are longer than their hands. They are
covered with reddish-brown hair, and the sides of the face, in adult
males, are commonly produced into two crescentic, flexible excrescences,
like fatty tumours. The Chimpanzees have arms which reach below the
knees; they have large thumbs and great toes, their hands are longer
than their feet, and their hair is black, while the skin of the face is
pale. The Gorilla, lastly, has arms which reach to the middle of the
leg, large thumbs and great toes, feet longer than the hands, a black
face, and dark-grey or dun hair.
For the purpose which I have at present in view, it is unnecessary that
I should enter into any further minutiæ respecting the distinctive
characters of the genera and species into which these man-like Apes are
divided by naturalists. Suffice it to say, that the Orangs and the
Gibbons constitute the distinct genera, _Simia_ and _Hylobates_; while
the Chimpanzees and Gorillas are by some regarded simply as distinct
species of one genus, _Troglodytes_; by others as distinct
genera--_Troglodytes_ being reserved for the Chimpanzees, and _Gorilla_
for the Engé-ena or Pongo.
* * * * *
Sound knowledge respecting the habits and mode of life of the man-like
Apes has been even more difficult of attainment than correct information
regarding their structure.
Once in a generation, a Wallace may be found physically, mentally, and
morally qualified to wander unscathed through the tropical wilds of
America and of Asia; to form magnificent collections as he wanders; and
withal to think out sagaciously the conclusions suggested by his
collections: but, to the ordinary explorer or collector, the dense
forests of equatorial Asia and Africa, which constitute the favourite
habitation of the Orang, the Chimpanzee, and the Gorilla, present
difficulties of no ordinary magnitude: and the man who risks his life by
even a short visit to the malarious shores of those regions may well be
excused if he shrinks from facing the dangers of the interior; if he
contents himself with stimulating the industry of the better seasoned
natives, and collecting and collating the more or less mythical reports
and traditions with which they are too ready to supply him.
In such a manner most of the earlier accounts of the habits of the
man-like Apes originated; and even now a good deal of what passes
current must be admitted to have no very safe foundation. The best
information we possess is that, based almost wholly on direct European
testimony, respecting the Gibbons; the next best evidence relates to the
Orangs; while our knowledge of the habits of the Chimpanzee and the
Gorilla stands much in need of support and enlargement by additional
testimony from instructed European eye-witnesses.
It will therefore be convenient in endeavouring to form a notion of what
we are justified in believing about these animals, to commence with the
best known man-like Apes, the Gibbons and Orangs; and to make use of the
perfectly reliable information respecting them as a sort of criterion of
the probable truth or falsehood of assertions respecting the others.
Of the GIBBONS, half a dozen species are found scattered over the
Asiatic islands, Java, Sumatra, Borneo, and through Malacca, Siam,
Arracan, and an uncertain extent of Hindostan, on the main land of Asia.
The largest attain a few inches above three feet in height, from the
crown to the heel, so that they are shorter than the other man-like
Apes; while the slenderness of their bodies renders their mass far
smaller in proportion even to this diminished height.
Dr. Salomon Müller, an accomplished Dutch naturalist, who lived for many
years in the Eastern Archipelago, and to the results of whose personal
experience I shall frequently have occasion to refer, states that the
Gibbons are true mountaineers, loving the slopes and edges of the hills,
though they rarely ascend beyond the limit of the fig-trees. All day
long they haunt the tops of the tall trees; and though, towards evening,
they descend in small troops to the open ground, no sooner do they spy a
man than they dart up the hill-sides, and disappear in the darker
valleys.
All observers testify to the prodigious volume of voice possessed by
these animals. According to the writer whom I have just cited, in one of
them, the Siamang, "the voice is grave and penetrating, resembling the
sounds g[=o]ek, g[=o]ek, g[=o]ek, g[=o]ek, goek ha ha ha ha
haa[=a][=a][=a], and may easily be heard at a distance of half a
league." While the cry is being uttered, the great membranous bag under
the throat which communicates with the organ of voice, the so-called
"laryngeal sac," becomes greatly distended, diminishing again when the
creature relapses into silence.
M. Duvaucel, likewise, affirms that the cry of the Siamang may be heard
for miles--making the woods ring again. So Mr. Martin[15] describes the
cry of the agile Gibbon as "overpowering and deafening" in a room, and
"from its strength, well calculated for resounding through the vast
forests." Mr. Waterhouse, an accomplished musician as well as zoologist,
says, "The Gibbon's voice is certainly much more powerful than that of
any singer I ever heard." And yet it is to be recollected that this
animal is not half the height of, and far less bulky in proportion than,
a man.
There is good testimony that various species of Gibbon readily take to
the erect posture. Mr. George Bennett,[16] a very excellent observer, in
describing the habits of a male _Hylobates syndactylus_ which remained
for some time in his possession, says: "He invariably walks in the erect
posture when on a level surface; and then the arms either hang down,
enabling him to assist himself with his knuckles; or what is more usual,
he keeps his arms uplifted in nearly an erect position, with the hands
pendent ready to seize a rope, and climb up on the approach of danger or
on the obtrusion of strangers. He walks rather quick in the erect
posture, but with a waddling gait, and is soon run down if, whilst
pursued, he has no opportunity of escaping by climbing.... When he walks
in the erect posture he turns the leg and foot outwards, which occasions
him to have a waddling gait and to seem bow-legged."
Dr. Burrough states of another Gibbon, the Horlack or Hooluk:
"They walk erect; and when placed on the floor, or in an
open field, balance themselves very prettily, by raising
their hands over their head and slightly bending the arm
at the wrist and elbow, and then run tolerably fast,
rocking from side to side; and, if urged to greater
speed, they let fall their hands to the ground, and
assist themselves forward, rather jumping than running,
still keeping the body, however, nearly erect."
Somewhat different evidence, however, is given by Dr. Winslow Lewis:[17]
"Their only manner of walking was on their posterior or inferior
extremities, the others being raised upwards to preserve their
equilibrium, as rope-dancers are assisted by long poles at fairs. Their
progression was not by placing one foot before the other, but by
simultaneously using both, as in jumping." Dr. Salomon Müller also
states that the Gibbons progress upon the ground by a short series of
tottering jumps, effected only by the hind limbs, the body being held
altogether upright.
[Illustration: FIG. 8.--A Gibbon (_H. pileatus_), after Wolf.]
But Mr. Martin (l. c. p. 418), who also speaks from direct observation,
says of the Gibbons generally:
"Pre-eminently qualified for arboreal habits, and
displaying among the branches amazing activity, the
Gibbons are not so awkward or embarrassed on a level
surface as might be imagined. They walk erect, with a
waddling or unsteady gait, but at a quick pace; the
equilibrium of the body requiring to be kept up, either
by touching the ground with the knuckles, first on one
side then on the other, or by uplifting the arms so as to
poise it. As with the Chimpanzee, the whole of the
narrow, long sole of the foot is placed upon the ground
at once and raised at once, without any elasticity of
step."
After this mass of concurrent and independent testimony, it cannot
reasonably be doubted that the Gibbons commonly and habitually assume
the erect attitude.
But level ground is not the place where these animals can display their
very remarkable and peculiar locomotive powers, and that prodigious
activity which almost tempts one to rank them among flying rather than
among ordinary climbing mammals.
Mr. Martin (l. c. p. 430) has given so excellent and graphic an account
of the movements of a _Hylobates agilis_, living in the Zoological
Gardens, in 1840, that I will quote it in full:
"It is almost impossible to convey in words an idea of
the quickness and graceful address of her movements: they
may indeed be termed aerial, as she seems merely to touch
in her progress the branches among which she exhibits her
evolutions. In these feats her hands and arms are the
sole organs of locomotion; her body hanging as if
suspended by a rope, sustained by one hand (the right,
for example), she launches herself, by an energetic
movement, to a distant branch, which she catches with the
left hand; but her hold is less than momentary: the
impulse for the next launch is acquired: the branch then
aimed at is attained by the right hand again, and quitted
instantaneously, and so on, in alternate succession. In
this manner spaces of twelve and eighteen feet are
cleared, with the greatest ease and uninterruptedly, for
hours together, without the slightest appearance of
fatigue being manifested; and it is evident that, if more
space could be allowed, distances very greatly exceeding
eighteen feet would be as easily cleared; so that
Duvaucel's assertion that he has seen these animals
launch themselves from one branch to another, forty feet
asunder, startling as it is, may be well credited.
Sometimes, on seizing a branch in her progress, she will
throw herself, by the power of one arm only, completely
round it, making a revolution with such rapidity as
almost to deceive the eye, and continue her progress with
undiminished velocity. It is singular to observe how
suddenly this Gibbon can stop, when the impetus given by
the rapidity and distance of her swinging leaps would
seem to require a gradual abatement of her movements. In
the very midst of her flight a branch is seized, the body
raised, and she is seen, as if by magic, quietly seated
on it, grasping it with her feet. As suddenly she again
throws herself into action.
"The following facts will convey some notion of her
dexterity and quickness. A live bird was let loose in her
apartment; she marked its flight, made a long swing to a
distant branch, caught the bird with one hand in her
passage, and attained the branch with her other hand; her
aim, both at the bird and at the branch, being as
successful as if one object only had engaged her
attention. It may be added that she instantly bit off the
head of the bird, picked its feathers, and then threw it
down without attempting to eat it.
"On another occasion this animal swung herself from a
perch, across a passage at least twelve feet wide,
against a window which it was thought would be
immediately broken: but not so; to the surprise of all,
she caught the narrow framework between the panes with
her hand, in an instant attained the proper impetus, and
sprang back again to the cage she had left--a feat
requiring not only great strength, but the nicest
precision."
The Gibbons appear to be naturally very gentle, but there is very good
evidence that they will bite severely when irritated--a female
_Hylobates agilis_ having so severely lacerated one man with her long
canines, that he died; while she had injured others so much that, by way
of precaution, these formidable teeth had been filed down; but, if
threatened, she would still turn on her keeper. The Gibbons eat insects,
but appear generally to avoid animal food. A Siamang, however, was seen
by Mr. Bennett to seize and devour greedily a live lizard. They commonly
drink by dipping their fingers in the liquid and then licking them. It
is asserted that they sleep in a sitting posture.
Duvaucel affirms that he has seen the females carry their young to the
waterside and there wash their faces, in spite of resistance and cries.
They are gentle and affectionate in captivity--full of tricks and
pettishness, like spoiled children, and yet not devoid of a certain
conscience, as an anecdote, told by Mr. Bennett (l. c. p. 156), will
show. It would appear that his Gibbon had a peculiar inclination for
disarranging things in the cabin. Among these articles, a piece of soap
would especially attract his notice, and for the removal of this he had
been once or twice scolded. "One morning," says Mr. Bennett, "I was
writing, the ape being present in the cabin, when casting my eyes
towards him, I saw the little fellow taking the soap. I watched him
without his perceiving that I did so: and he occasionally would cast a
furtive glance towards the place where I sat. I pretended to write; he,
seeing me busily occupied, took the soap, and moved away with it in his
paw. When he had walked half the length of the cabin, I spoke quietly,
without frightening him. The instant he found I saw him, he walked back
again, and deposited the soap nearly in the same place from whence he
had taken it. There was certainly something more than instinct in that
action: he evidently betrayed a consciousness of having done wrong both
by his first and last actions--and what is reason if that is not an
exercise of it?"
* * * * *
The most elaborate account of the natural history of the ORANG-UTAN
extant, is that given in the "Verhandelingen over de Natuurlijke
Geschiedenis der Nederlandsche overzeesche Bezittingen (1839-45)," by
Dr. Salomon Müller and Dr. Schlegel, and I shall base what I have to say
upon this subject almost entirely on their statements, adding, here and
there, particulars of interest from the writings of Brooke, Wallace, and
others.
[Illustration: FIG. 9.--An adult male Orang-Utan, after Müller and
Schlegel.]
The Orang-Utan would rarely seem to exceed four feet in height, but the
body is very bulky, measuring two-thirds of the height in
circumference.[18]
The Orang-Utan is found only in Sumatra and Borneo, and is common in
neither of these islands--in both of which it occurs always in low, flat
plains, never in the mountains. It loves the densest and most sombre of
the forests, which extend from the sea-shore inland, and thus is found
only in the eastern half of Sumatra, where alone such forests occur,
though, occasionally, it strays over to the western side.
On the other hand, it is generally distributed through Borneo, except in
the mountains, or where the population is dense. In favourable places,
the hunter may, by good fortune, see three or four in a day.
Except in the pairing time, the old males usually live by themselves.
The old females, and the immature males, on the other hand, are often
met with in twos and threes; and the former occasionally have young with
them, though the pregnant females usually separate themselves, and
sometimes remain apart after they have given birth to their offspring.
The young Orangs seem to remain unusually long under their mother's
protection, probably in consequence of their slow growth. While
climbing, the mother always carries her young against her bosom, the
young holding on by his mother's hair.[19] At what time of life the
Orang-Utan becomes capable of propagation, and how long the females go
with young, is unknown, but it is probable that they are not adult until
they arrive at ten or fifteen years of age. A female which lived for
five years at Batavia, had not attained one-third the height of the wild
females. It is probable that, after reaching adult years, they go on
growing, though slowly, and that they live to forty or fifty years. The
Dyaks tell of old Orangs, which have not only lost all their teeth, but
which find it so troublesome to climb, that they maintain themselves on
windfalls and juicy herbage.
The Orang is sluggish, exhibiting none of that marvellous activity
characteristic of the Gibbons. Hunger alone seems to stir him to
exertion, and when it is stilled he relapses into repose. When the
animal sits, it curves its back and bows its head, so as to look
straight down on the ground; sometimes it holds on with its hands by a
higher branch, sometimes lets them hang phlegmatically down by its
side--and in these positions the Orang will remain, for hours together,
in the same spot, almost without stirring, and only now and then giving
utterance to its deep, growling voice. By day, he usually climbs from
one tree-top to another, and only at night descends to the ground, and
if then threatened with danger, he seeks refuge among the underwood.
When not hunted, he remains a long time in the same locality, and
sometimes stops for many days on the same tree--a firm place among its
branches serving him for a bed. It is rare for the Orang to pass the
night in the summit of a large tree, probably because it is too windy
and cold there for him; but, as soon as night draws on, he descends from
the height and seeks out a fit bed in the lower and darker part, or in
the leafy top of a small tree, among which he prefers Nibong Palms,
Pandani, or one of those parasitic Orchids which give the primæval
forests of Borneo so characteristic and striking an appearance. But
wherever he determines to sleep, there he prepares himself a sort of
nest: little boughs and leaves are drawn together round the selected
spot, and bent crosswise over one another; while to make the bed soft,
great leaves of Ferns, of Orchids, of _Pandanus fascicularis_, _Nipa
fruticans_, &c., are laid over them. Those which Müller saw, many of
them being very fresh, were situated at a height of ten to twenty-five
feet above the ground, and had a circumference, on the average, of two
or three feet. Some were packed many inches thick with _Pandanus_
leaves; others were remarkable only for the cracked twigs, which, united
in a common centre, formed a regular platform. "The rude _hut_," says
Sir James Brooke, "which they are stated to build in the trees, would be
more properly called a seat or nest, for it has no roof or cover of any
sort. The facility with which they form this nest is curious, and I had
an opportunity of seeing a wounded female weave the branches together
and seat herself, within a minute."
According to the Dyaks, the Orang rarely leaves his bed before the sun
is well above the horizon and has dissipated the mists. He gets up about
nine, and goes to bed again about five; but sometimes not till late in
the twilight. He lies sometimes on his back; or, by way of change, turns
on one side or the other, drawing his limbs up to his body, and resting
his head on his hand. When the night is cold, windy, or rainy, he
usually covers his body with a heap of _Pandanus_, _Nipa_, or Fern
leaves, like those of which his bed is made, and he is especially
careful to wrap up his head in them. It is this habit of covering
himself up which has probably led to the fable that the Orang builds
huts in the trees.
Although the Orang resides mostly amid the boughs of great trees, during
the daytime, he is very rarely seen squatting on a thick branch, as
other apes, and particularly the Gibbons, do. The Orang, on the
contrary, confines himself to the slender leafy branches, so that he is
seen right at the top of the trees, a mode of life which is closely
related to the constitution of his hinder limbs, and especially to that
of his seat. For this is provided with no callosities, such as are
possessed by many of the lower apes, and even by the Gibbons; and those
bones of the pelvis, which are termed the ischia, and which form the
solid framework of the surface on which the body rests in the sitting
posture, are not expanded like those of the apes which possess
callosities, but are more like those of man.
An Orang climbs so slowly and cautiously,[20] as, in this act, to
resemble a man more than an ape, taking great care of his feet, so that
injury of them seems to affect him far more than it does other apes.
Unlike the Gibbons, whose forearms do the greater part of the work, as
they swing from branch to branch, the Orang never makes even the
smallest jump. In climbing, he moves alternately one hand and one foot,
or, after having laid fast hold with the hands, he draws up both feet
together. In passing from one tree to another, he always seeks out a
place where the twigs of both come close together, or interlace. Even
when closely pursued, his circumspection is amazing: he shakes the
branches to see if they will bear him, and then bending an overhanging
bough down by throwing his weight gradually along it, he makes a bridge
from the tree he wishes to quit to the next.[21]
On the ground the Orang always goes laboriously and shakily, on all
fours. At starting he will run faster than a man, though he may soon be
overtaken. The very long arms which, when he runs, are but little bent,
raise the body of the Orang remarkably, so that he assumes much the
posture of a very old man bent down by age, and making his way along by
the help of a stick. In walking, the body is usually directed straight
forward, unlike the other apes, which run more or less obliquely; except
the Gibbons, who in these, as in so many other respects, depart
remarkably from their fellows.
The Orang cannot put its feet flat on the ground, but is supported upon
their outer edges, the heel resting more on the ground, while the curved
toes partly rest upon the ground by the upper side of their first joint,
the two outermost toes of each foot completely resting on this surface.
The hands are held in the opposite manner, their inner edges serving as
the chief support. The fingers are then bent out in such a manner that
their foremost joints, especially those of the two innermost fingers,
rest upon the ground by their upper sides, while the point of the free
and straight thumb serves as an additional fulcrum.
The Orang never stands on its hind legs, and all the pictures,
representing it as so doing, are as false as the assertion that it
defends itself with sticks, and the like.
The long arms are of especial use, not only in climbing, but in the
gathering of food from boughs to which the animal could not trust his
weight. Figs, blossoms, and young leaves of various kinds, constitute
the chief nutriment of the Orang; but strips of bamboo two or three feet
long were found in the stomach of a male. They are not known to eat
living animals.
Although, when taken young, the Orang-Utan soon becomes domesticated,
and indeed seems to court human society, it is naturally a very wild and
shy animal, though apparently sluggish and melancholy. The Dyaks affirm,
that when the old males are wounded with arrows only, they will
occasionally leave the trees and rush raging upon their enemies, whose
sole safety lies in instant flight, as they are sure to be killed if
caught.[22]
But, though possessed of immense strength, it is rare for the Orang to
attempt to defend itself, especially when attacked with fire-arms. On
such occasions he endeavours to hide himself, or to escape along the
topmost branches of the trees, breaking off and throwing down the
boughs as he goes. When wounded he betakes himself to the highest
attainable point of the tree, and emits a singular cry, consisting at
first of high notes, which at length deepen into a low roar, not unlike
that of a panther. While giving out the high notes the Orang thrusts out
his lips into a funnel shape; but in uttering the low notes he holds his
mouth wide open, and at the same time the great throat bag, or laryngeal
sac, becomes distended.
According to the Dyaks, the only animal the Orang measures his strength
with is the crocodile, who occasionally seizes him on his visits to the
water side. But they say that the Orang is more than a match for his
enemy, and beats him to death, or rips up his throat by pulling the jaws
asunder!
Much of what has been here stated was probably derived by Dr. Müller
from the reports of his Dyak hunters; but a large male, four feet high,
lived in captivity, under his observation, for a month, and receives a
very bad character.
"He was a very wild beast," says Müller, "of prodigious strength, and
false and wicked to the last degree. If any one approached he rose up
slowly with a low growl, fixed his eyes in the direction in which he
meant to make his attack, slowly passed his hand between the bars of his
cage, and then extending his long arm, gave a sudden grip--usually at
the face." He never tried to bite (though Orangs will bite one another),
his great weapons of offence and defence being his hands.
His intelligence was very great; and Müller remarks, that though the
faculties of the Orang have been estimated too highly, yet Cuvier, had
he seen this specimen, would not have considered its intelligence to be
only a little higher than that of the dog.
His hearing was very acute, but the sense of vision seemed to be less
perfect. The under lip was the great organ of touch, and played a very
important part in drinking, being thrust out like a trough, so as either
to catch the falling rain, or to receive the contents of the half
cocoa-nut shell full of water with which the Orang was supplied, and
which, in drinking, he poured into the trough thus formed.
In Borneo the Orang-Utan of the Malays goes by the name of "_Mias_"
among the Dyaks, who distinguish several kinds as _Mias Pappan_, or
_Zimo_, _Mias Kassu_, and _Mias Rambi_. Whether these are distinct
species, however, or whether they are mere races, and how far any of
them are identical with the Sumatran Orang, as Mr. Wallace thinks the
Mias Pappan to be, are problems which are at present undecided; and the
variability of these great apes is so extensive, that the settlement of
the question is a matter of great difficulty. Of the form called "Mias
Pappan," Mr. Wallace[23] observes, "It is known by its large size, and
by the lateral expansion of the face into fatty protuberances, or
ridges, over the temporal muscles, which have been mis-termed
_callosities_, as they are perfectly soft, smooth, and flexible. Five of
this form, measured by me, varied only from 4 feet 1 inch to 4 feet 2
inches in height, from the heel to the crown of the head, the girth of
the body from 3 feet to 3 feet 7-1/2 inches, and the extent of the
outstretched arms from 7 feet 2 inches to 7 feet 6 inches; the width of
the face from 10 to 13-1/4 inches. The colour and length of the hair
varied in different individuals, and in different parts of the same
individual; some possessed a rudimentary nail on the great toe, others
none at all; but they otherwise present no external differences on which
to establish even varieties of a species.
"Yet, when we examine the crania of these individuals, we find
remarkable differences of form, proportion, and dimension, no two being
exactly alike. The slope of the profile, and the projection of the
muzzle, together with the size of the cranium, offer differences as
decided as those existing between the most strongly marked forms of the
Caucasian and African crania in the human species. The orbits vary in
width and height, the cranial ridge is either single or double, either
much or little developed, and the zygomatic aperture varies considerably
in size. This variation in the proportions of the crania enables us
satisfactorily to explain the marked difference presented by the
single-crested and double-crested skulls, which have been thought to
prove the existence of two large species of Orang. The external surface
of the skull varies considerably in size, as do also the zygomatic
aperture and the temporal muscle; but they bear no necessary relation to
each other, a small muscle often existing with a large cranial surface,
and _vice versâ_. Now, those skulls which have the largest and strongest
jaws and the widest zygomatic aperture, have the muscles so large that
they meet on the crown of the skull, and deposit the bony ridge which
separates them, and which is the highest in that which has the smallest
cranial surface. In those which combine a large surface with
comparatively weak jaws, and small zygomatic aperture, the muscles, on
each side, do not extend to the crown, a space of from 1 to 2 inches
remaining between them, and along their margins small ridges are formed.
Intermediate forms are found, in which the ridges meet only in the
hinder part of the skull. The form and size of the ridges are therefore
independent of age, being sometimes more strongly developed in the less
aged animal. Professor Temminck states that the series of skulls in the
Leyden Museum shows the same result."
Mr. Wallace observed two male adult Orangs (Mias Kassu of the Dyaks),
however, so very different from any of these that he concludes them to
be specifically distinct; they were respectively 3 feet 8-1/2 inches and
3 feet 9-1/2 inches high, and possessed no sign of the cheek
excrescences, but otherwise resembled the larger kinds. The skull has
no crest, but two bony ridges, 1-3/4 inches to 2 inches apart, as in the
_Simia morio_ of Professor Owen. The teeth, however, are immense,
equalling or surpassing those of the other species. The females of both
these kinds, according to Mr. Wallace, are devoid of excrescences, and
resemble the smaller males, but are shorter by 1-1/2 to 3 inches, and
their canine teeth are comparatively small, subtruncated and dilated at
the base, as in the so-called _Simia morio_, which is, in all
probability, the skull of a female of the same species as the smaller
males. Both males and females of this smaller species are
distinguishable, according to Mr. Wallace, by the comparatively large
size of the middle incisors of the upper jaw.
* * * * *
So far as I am aware, no one has attempted to dispute the accuracy of
the statements which I have just quoted regarding the habits of the two
Asiatic man-like Apes; and if true, they must be admitted as evidence,
that such an Ape--
1stly, May readily move along the ground in the erect, or semi-erect,
position, and without direct support from its arms.
2ndly, That it may possess an extremely loud voice, so loud as to be
readily heard one or two miles.
3rdly, That it may be capable of great viciousness and violence when
irritated: and this is especially true of adult males.
4thly, That it may build a nest to sleep in.
Such being well-established facts respecting the Asiatic Anthropoids,
analogy alone might justify us in expecting the African species to offer
similar peculiarities, separately or combined; or, at any rate, would
destroy the force of any attempted _à priori_ argument against such
direct testimony as might be adduced in favour of their existence. And,
if the organization of any of the African Apes could be demonstrated to
fit it better than either of its Asiatic allies for the erect position
and for efficient attack, there would be still less reason for doubting
its occasional adoption of the upright attitude or of aggressive
proceedings.
From the time of Tyson and Tulpius downwards, the habits of the young
CHIMPANZEE in a state of captivity have been abundantly reported and
commented upon. But trustworthy evidence as to the manners and customs
of adult anthropoids of this species, in their native woods, was almost
wanting up to the time of the publication of the paper by Dr. Savage, to
which I have already referred; containing notes of the observations
which he made, and of the information which he collected from sources
which he considered trustworthy, while resident at Cape Palmas, at the
north-western limit of the Bight of Benin.
The adult Chimpanzees, measured by Dr. Savage, never exceeded, though
the males may almost attain, five feet in height.
"When at rest, the sitting posture is that generally
assumed. They are sometimes seen standing and walking,
but when thus detected, they immediately take to all
fours, and flee from the presence of the observer. Such
is their organization that they cannot stand erect, but
lean forward. Hence they are seen, when standing, with
the hands clasped over the occiput, or the lumbar region,
which would seem necessary to balance or ease of posture.
"The toes of the adult are strongly flexed and turned
inwards, and cannot be perfectly straightened. In the
attempt the skin gathers into thick folds on the back,
shewing that the full expansion of the foot, as is
necessary in walking, is unnatural. The natural position
is on all fours, the body anteriorly resting upon the
knuckles. These are greatly enlarged, with the skin
protuberant and thickened like the sole of the foot.
"They are expert climbers, as one would suppose from
their organization. In their gambols they swing from limb
to limb to a great distance, and leap with astonishing
agility. It is not unusual to see the 'old folks' (in the
language of an observer) sitting under a tree regaling
themselves with fruit and friendly chat, while their
'children' are leaping around them, and swinging from
tree to tree with boisterous merriment.
"As seen here, they cannot be called _gregarious_, seldom
more than five, or ten at most, being found together. It
has been said, on good authority, that they occasionally
assemble in large numbers, in gambols. My informant
asserts that he saw once not less than fifty so engaged;
hooting, screaming, and drumming with sticks upon old
logs, which is done in the latter case with equal
facility by the four extremities. They do not appear ever
to act on the offensive, and seldom, if ever really, on
the defensive. When about to be captured, they resist by
throwing their arms about their opponent, and attempting
to draw him into contact with their teeth." (Savage, l.
c. p. 384.)
With respect to this last point Dr. Savage is very explicit in another
place:
"_Biting_ is their principal art of defence. I have seen
one man who had been thus severely wounded in the feet.
"The strong development of the canine teeth in the adult
would seem to indicate a carnivorous propensity; but in
no state save that of domestication do they manifest it.
At first they reject flesh, but easily acquire a fondness
for it. The canines are early developed, and evidently
designed to act the important part of weapons of defence.
When in contact with man almost the first effort of the
animal is--_to bite_.
"They avoid the abodes of men, and build their
habitations in trees. Their construction is more that of
_nests_ than _hut_, as they have been erroneously termed
by some naturalists. They generally build not far above
the ground. Branches or twigs are bent, or partly broken,
and crossed, and the whole supported by the body of a
limb or a crotch. Sometimes a nest will be found near the
_end_ of a _strong leafy branch_ twenty or thirty feet
from the ground. One I have lately seen that could not be
less than forty feet, and more probably it was fifty. But
this is an unusual height.
"Their dwelling-place is not permanent, but changed in
pursuit of food and solitude, according to the force of
circumstances. We more often see them in elevated places;
but this arises from the fact that the low grounds, being
more favourable for the natives' rice-farms, are the
oftener cleared, and hence are almost always wanting in
suitable trees for their nests.... It is seldom that more
than one or two nests are seen upon the same tree, or in
the same neighbourhood: five have been found, but it was
an unusual circumstance....
"They are very filthy in their habits.... It is a
tradition with the natives generally here, that they were
once members of their own tribe: that for their depraved
habits they were expelled from all human society, and,
that through an obstinate indulgence of their vile
propensities, they have degenerated into their present
state and organization. They are, however, eaten by them,
and when cooked with the oil and pulp of the palm-nut
considered a highly palatable morsel.
"They exhibit a remarkable degree of intelligence in
their habits, and, on the part of the mother, much
affection for their young. The second female described
was upon a tree when first discovered, with her mate and
two young ones (a male and a female). Her first impulse
was to descend with great rapidity, and make off into the
thicket, with her mate and female offspring. The young
male remaining behind, she soon returned to the rescue.
She ascended and took him in her arms, at which moment
she was shot, the ball passing through the forearm of the
young one, on its way to the heart of the mother....
"In a recent case, the mother, when discovered, remained
upon the tree with her offspring, watching intently the
movements of the hunter. As he took aim, she motioned
with her hand, precisely in the manner of a human being,
to have him desist and go away. When the wound has not
proved instantly fatal, they have been known to stop the
flow of blood by pressing with the hand upon the part,
and when this did not succeed, to apply leaves and
grass.... When shot, they give a sudden screech, not
unlike that of a human being in sudden and acute
distress."
The ordinary voice of the Chimpanzee, however, is affirmed to be hoarse,
guttural, and not very loud, somewhat like "whoo-whoo" (l. c. p. 365).
The analogy of the Chimpanzee to the Orang, in its nest-building habit
and in the mode of forming its nest, is exceedingly interesting; while,
on the other hand, the activity of this ape, and its tendency to bite,
are particulars in which it rather resembles the Gibbons. In extent of
geographical range, again, the Chimpanzees--which are found from Sierra
Leone to Congo--remind one of the Gibbons, rather than of either of
the other man-like Apes; and it seems not unlikely that, as is the case
with the Gibbons, there may be several species spread over the
geographical area of the genus.
The same excellent observer, from whom I have borrowed the preceding
account of the habits of the adult Chimpanzee, published, fifteen years
ago,[24] an account of the GORILLA, which has, in its most essential
points, been confirmed by subsequent observers, and to which so very
little has really been added, that in justice to Dr. Savage I give it
almost in full.
"It should be borne in mind that my account is based upon
the statements of the aborigines of that region (the
Gaboon). In this connection, it may also be proper for me
to remark, that having been a missionary resident for
several years, studying, from habitual intercourse, the
African mind and character, I felt myself prepared to
discriminate and decide upon the probability of their
statements. Besides, being familiar with the history and
habits of its interesting congener (_Trog. niger_,
Geoff.), I was able to separate their accounts of the two
animals, which, having the same locality and a similarity
of habit, are confounded in the minds of the mass,
especially as but few--such as traders to the interior
and huntsmen--have ever seen the animal in question.
"The tribe from which our knowledge of the animal is
derived, and whose territory forms its habitat, is the
_Mpongwe_, occupying both banks of the River Gaboon, from
its mouth to some fifty or sixty miles upward....
"If the word 'Pongo' be of African origin, it is probably
a corruption of the word _Mpongwe_, the name of the tribe
on the banks of the Gaboon, and hence applied to the
region they inhabit. Their local name for the Chimpanzee
is _Enché-eko_, as near as it can be Anglicized, from
which the common term 'Jocko' probably comes. The Mpongwe
appellation for its new congener is _Engé-ena_,
prolonging the sound of the first vowel, and slightly
sounding the second.
[Illustration: FIG. 10.--The Gorilla (after Wolff).]
"The habitat of the _Engé-ena_ is the interior of lower
Guinea, whilst that of the _Enché-eko_ is nearer the
sea-board.
"Its height is about five feet; it is disproportionately
broad across the shoulders, thickly covered with coarse
black hair, which is said to be similar in its
arrangement to that of the _Enché-eko_; with age it
becomes grey, which fact has given rise to the report
that both animals are seen of different colours.
"_Head._--The prominent features of the head are, the
great width and elongation of the face, the depth of the
molar region, the branches of the lower jaw being very
deep and extending far backward, and the comparative
smallness of the cranial portion; the eyes are very
large, and said to be like those of the Enché-eko, a
bright hazel; nose broad and flat, slightly elevated
towards the root; the muzzle broad, and prominent lips
and chin, with scattered grey hairs; the under lip highly
mobile, and capable of great elongation when the animal
is enraged, then hanging over the chin; skin of the face
and ears naked, and of a dark brown, approaching to
black.
"The most remarkable feature of the head is a high ridge,
or crest of hair, in the course of the sagittal suture,
which meets posteriorly with a transverse ridge of the
same, but less prominent, running round from the back of
one ear to the other. The animal has the power of moving
the scalp freely forward and back, and when enraged is
said to contract it strongly over the brow, thus bringing
down the hairy ridge and pointing the hair forward, so as
to present an indescribably ferocious aspect.
"Neck short, thick, and hairy; chest and shoulders very
broad, said to be fully double the size of the
Enché-ekos; arms very long, reaching some way below the
knee--the forearm much the shortest; hands very large,
the thumbs much larger than the fingers....
"The gait is shuffling; the motion of the body, which is
never upright as in man, but bent forward, is somewhat
rolling, or from side to side. The arms being longer than
the Chimpanzee, it does not stoop as much in walking;
like that animal, it makes progression by thrusting its
arms forward, resting the hands on the ground, and then
giving the body a half jumping half swinging motion
between them. In this act it is said not to flex the
fingers, as does the Chimpanzee, resting on its
knuckles, but to extend them, making a fulcrum of the
hand. When it assumes the walking posture, to which it is
said to be much inclined, it balances its huge body by
flexing its arms upward.
"They live in bands, but are not so numerous as the
Chimpanzees: the females generally exceed the other sex
in number. My informants all agree in the assertion that
but one adult male is seen in a band; that when the young
males grow up, a contest takes place for mastery, and the
strongest, by killing and driving out the others,
establishes himself as the head of the community."
Dr. Savage repudiates the stories about the Gorillas carrying off women
and vanquishing elephants, and then adds:
"Their dwellings, if they may be so called, are similar
to those of the Chimpanzee, consisting simply of a few
sticks and leafy branches, supported by the crotches and
limbs of trees: they afford no shelter, and are occupied
only at night.
[Illustration: FIG. 11.--Gorilla walking (after Wolff).]
"They are exceedingly ferocious, and always offensive in
their habits, never running from man, as does the
Chimpanzee. They are objects of terror to the natives,
and are never encountered by them except on the
defensive. The few that have been captured were killed by
elephant-hunters and native traders, as they came
suddenly upon them while passing through the forests.
"It is said that when the male is first seen he gives a
terrific yell, that resounds far and wide through the
forest, something like kh--ah! kh--ah! prolonged and
shrill. His enormous jaws are widely opened at each
expiration, his under lip hangs over the chin, and the
hairy ridge and scalp are contracted upon the brow,
presenting an aspect of indescribable ferocity.
"The females and young, at the first cry, quickly
disappear. He then approaches the enemy in great fury,
pouring out his horrid cries in quick succession. The
hunter awaits his approach with his gun extended: if his
aim is not sure, he permits the animal to grasp the
barrel, and as he carries it to his mouth (which is his
habit) he fires. Should the gun fail to go off, the
barrel (that of the ordinary musket, which is thin) is
crushed between his teeth, and the encounter soon proves
fatal to the hunter.
"In the wild state, their habits are in general like
those of the _Troglodytes niger_, building their nests
loosely in trees, living on similar fruits, and changing
their place of resort from force of circumstances."
Dr. Savage's observations were confirmed and supplemented by those of
Mr. Ford, who communicated an interesting paper on the Gorilla to the
Philadelphian Academy of Sciences, in 1852. With respect to the
geographical distribution of this greatest of all the man-like Apes, Mr.
Ford remarks:
"This animal inhabits the range of mountains that
traverse the interior of Guinea, from the Cameroon in the
north, to Angola in the south, and about 100 miles
inland, and called by the geographers Crystal Mountains.
The limit to which this animal extends, either north or
south, I am unable to define. But that limit is doubtless
some distance north of this river [Gaboon]. I was able to
certify myself of this fact in a late excursion to the
head-waters of the Mooney (Danger) River, which comes
into the sea some sixty miles from this place. I was
informed (credibly, I think) that they were numerous
among the mountains in which that river rises, and far
north of that.
"In the south, this species extends to the Congo River,
as I am told by native traders who have visited the coast
between the Gaboon and that river. Beyond that, I am not
informed. This animal is only found at a distance from
the coast in most cases, and, according to my best
information, approaches it nowhere so nearly as on the
south side of this river, where they have been found
within ten miles of the sea. This, however, is only of
late occurrence. I am informed by some of the oldest
Mpongwe men that formerly he was only found on the
sources of the river, but that at present he may be
found within half-a-day's walk of its mouth. Formerly he
inhabited the mountainous ridge where Bushmen alone
inhabited, but now he boldly approaches the Mpongwe
plantations. This is doubtless the reason of the scarcity
of information in years past, as the opportunities for
receiving a knowledge of the animal have not been
wanting; traders having for one hundred years frequented
this river, and specimens, such as have been brought here
within a year, could not have been exhibited without
having attracted the attention of the most stupid."
One specimen Mr. Ford examined weighed 170 lbs., without the thoracic,
or pelvic, viscera, and measured four feet four inches round the chest.
This writer describes so minutely and graphically the onslaught of the
Gorilla--though he does not for a moment pretend to have witnessed the
scene--that I am tempted to give this part of his paper in full, for
comparison with other narratives:
"He always rises to his feet when making an attack,
though he approaches his antagonist in a stooping
posture.
"Though he never lies in wait, yet, when he hears, sees,
or scents a man, he immediately utters his characteristic
cry, prepares for an attack, and always acts on the
offensive. The cry he utters resembles a grunt more than
a growl, and is similar to the cry of the Chimpanzee,
when irritated, but vastly louder. It is said to be
audible at a great distance. His preparation consists in
attending the females and young ones, by whom he is
usually accompanied, to a little distance. He, however,
soon returns, with his crest erect and projecting
forward, his nostrils dilated, and his under-lip thrown
down; at the same time uttering his characteristic yell,
designed, it would seem, to terrify his antagonist.
Instantly, unless he is disabled by a well-directed shot,
he makes an onset, and, striking his antagonist with the
palm of his hands, or seizing him with a grasp from which
there is no escape, he dashes him upon the ground, and
lacerates him with his tusks.
"He is said to seize a musket, and instantly crush the
barrel between his teeth.... This animal's savage nature
is very well shewn by the implacable desperation of a
young one that was brought here. It was taken very young,
and kept four months, and many means were used to tame
it; but it was incorrigible, so that it bit me an hour
before it died."
Mr. Ford discredits the house-building and elephant-driving stories, and
says that no well-informed natives believe them. They are tales told to
children.
I might quote other testimony to a similar effect, but, as it appears to
me, less carefully weighed and sifted, from the letters of MM. Franquet
and Gautier Laboullay, appended to the memoir of M. I. G. St. Hilaire,
which I have already cited.
Bearing in mind what is known regarding the Orang and the Gibbon, the
statements of Dr. Savage and Mr. Ford do not appear to me to be justly
open to criticism on _à priori_ grounds. The Gibbons, as we have seen,
readily assume the erect posture, but the Gorilla is far better fitted
by its organization for that attitude than are the Gibbons: if the
laryngeal pouches of the Gibbons, as is very likely, are important in
giving volume to a voice which can be heard for half a league, the
Gorilla, which has similar sacs, more largely developed, and whose bulk
is fivefold that of a Gibbon, may well be audible for twice that
distance. If the Orang fights with its hands, the Gibbons and
Chimpanzees with their teeth, the Gorilla may, probably enough, do
either or both; nor is there anything to be said against either
Chimpanzee or Gorilla building a nest, when it is proved that the
Orang-Utan habitually performs that feat.
With all this evidence, now ten to fifteen years old, before the world,
it is not a little surprising that the assertions of a recent traveller,
who, so far as the Gorilla is concerned, really does very little more
than repeat, on his own authority, the statements of Savage and of Ford,
should have met with so much and such bitter opposition. If subtraction
be made of what was known before, the sum and substance of what M. Du
Chaillu has affirmed as a matter of his own observation respecting the
Gorilla, is, that, in advancing to the attack, the great brute beats his
chest with his fists. I confess I see nothing very improbable, or very
much worth disputing about, in this statement.
With respect to the other man-like Apes of Africa, M. Du Chaillu tells
us absolutely nothing, of his own knowledge, regarding the common
Chimpanzee; but he informs us of a bald-headed species or variety, the
_nschiego mbouve_, which builds itself a shelter, and of another rare
kind with a comparatively small face, large facial angle, and peculiar
note, resembling "Kooloo."
As the Orang shelters itself with a rough coverlet of leaves, and the
common Chimpanzee, according to that eminently trustworthy observer Dr.
Savage, makes a sound like "Whoo-whoo,"--the grounds of the summary
repudiation with which M. Du Chaillu's statements on these matters have
been met is not obvious.
If I have abstained from quoting M. Du Chaillu's work, then, it is not
because I discern any inherent improbability in his assertions
respecting the man-like Apes; nor from any wish to throw suspicion on
his veracity; but because, in my opinion, so long as his narrative
remains in its present state of unexplained and apparently inexplicable
confusion, it has no claim to original authority respecting any subject
whatsoever.
It may be truth, but it is not evidence.
FOOTNOTES:
[1] REGNUM CONGO: hoc est VERA DESCRIPTIO REGNI AFRICANI QUOD TAM AB
INCOLIS QUAM LUSITANIS CONGUS APPELLATUR, per Philippum Pigafettam, olim
ex Edoardo Lopez acroamatis lingua Italica excerpta, num Latio sermone
donata ab August. Cassiod. Reinio. Iconibus et imaginibus rerum
memorabilium quasi vivis, opera et industria Joan. Theodori et Joan.
Israelis de Bry, fratrum exornata. Francofurti, MDXCVIII.
[2] "Except this that their legges had no calves."--[Ed. 1626.] And in a
marginal note, "These great apes are called Pongo's."
[3] _Purchas' note._--Cape Negro is in 16 degrees south of the line.
[4] Purchas' marginal note, p. 982:--"The Pongo a giant ape. He told me
in conference with him, that one of these Pongoes tooke a negro boy of
his which lived a moneth with them. For they hurt not those which they
surprise at unawares, except they look on them; which he avoyded. He
said their highth was like a man's, but their bignesse twice as great. I
saw the negro boy. What the other monster should be he hath forgotten to
relate; and these papers came to my hand since his death, which,
otherwise, in my often conferences, I might have learned. Perhaps he
meaneth the Pigmy Pongo killers mentioned."
[5] Archives du Museum, tome x.
[6] I am indebted to Dr. Wright, of Cheltenham, whose paleontological
labours are so well known, for bringing this interesting relic to my
knowledge. Tyson's granddaughter, it appears, married Dr. Allardyce, a
physician of repute in Cheltenham, and brought, as part of her dowry,
the skeleton of the "Pygmie." Dr. Allardyce presented it to the
Cheltenham Museum, and, through the good offices of my friend Dr.
Wright, the authorities of the Museum have permitted me to borrow, what
is, perhaps, its most remarkable ornament.
[7] "Mandrill" seems to signify a "man-like ape," the word "Drill" or
"Dril" having been anciently employed in England to denote an Ape or
Baboon. Thus in the fifth edition of Blount's "Glossographia, or a
Dictionary interpreting the hard words of whatsoever language now used
in our refined English tongue ... very useful for all such as desire to
understand what they read," published in 1681, I find, "Dril--a
stone-cutter's tool wherewith he bores little holes in marble, &c. Also
a large overgrown Ape and Baboon, so called." "Drill" is used in the
same sense in Charleton's "Onomasticon Zoicon," 1668. The singular
etymology of the word given by Buffon seems hardly a probable one.
[8] Histoire Naturelle, Suppl. tome 7ème, 1789.
[9] Camper, OEuvres, i. p. 56.
[10] Verhandelingen van het Bataviaasch Genootschap. Tweede Deel. Derde
Druk. 1826.
[11] "Briefe des Herrn v. Wurmb und des H. Baron von Wollzogen. Gotha,
1794."
[12] See Blumenbach, "Abbildungen Naturhistorichen Gegenstände," No. 12,
1810; and Tilesius, "Naturhistoriche Früchte der ersten
Kaiserlich-Russischen Erdumsegelung," p. 115, 1813.
[13] Speaking broadly and without prejudice to the question, whether
there be more than one species of Orang.
[14] See "Observations on the external characters and habits of the
Troglodytes niger, by Thomas N. Savage, M.D., and on its organization,
by Jeffries Wyman, M.D.," Boston Journal of Natural History, vol. iv.,
1843-4; and "External characters, habits, and osteology of Troglodytes
Gorilla," by the same authors, ibid., vol. v., 1847.
[15] "Man and Monkies," p. 423.
[16] "Wanderings in New South Wales," vol. ii. chap. viii., 1834.
[17] Boston Journal of Natural History, vol. i., 1834.
[18] The largest Orang-Utan, cited by Temminck, measured, when standing
upright, 4 ft.; but he mentions having just received news of the capture
of an Orang 5 ft. 3 in. high. Schlegel and Müller say that their largest
old male measured, upright, 1.25 Netherlands "el"; and from the crown to
the end of the toes, 1.5 el; the circumference of the body being about 1
el. The largest old female was 1.09 el high, when standing. The adult
skeleton in the College of Surgeons' Museum, if set upright, would stand
3 ft. 6-8 in. from crown to sole. Dr. Humphry gives 3 ft. 8 in. as the
mean height of two Orangs. Of seventeen Orangs examined by Mr. Wallace,
the largest was 4 ft. 2 in. high, from the heel to the crown of the
head. Mr. Spencer St. John, however, in his "Life in the Forests of the
Far East," tells us of an Orang of "5 ft. 2 in., measuring fairly from
the head to the heel," 15 in. across the face, and 12 in. round the
wrist. It does not appear, however, that Mr. St. John measured this
Orang himself.
[19] See Mr. Wallace's account of an infant "Orang-utan," in the "Annals
of Natural History" for 1856. Mr. Wallace provided his interesting
charge with an artificial mother of buffalo-skin, but the cheat was too
successful. The infant's entire experience led it to associate teats
with hair, and feeling the latter, it spent its existence in vain
endeavours to discover the former.
[20] "They are the slowest and least active of all the monkey tribe, and
their motions are surprisingly awkward and uncouth."--Sir James Brooke,
in the "Proceedings of the Zoological Society," 1841.
[21] Mr. Wallace's account of the progression of the Orang almost
exactly corresponds with this.
[22] Sir James Brooke, in a letter to Mr. Waterhouse, published in the
proceedings of the Zoological Society for 1841, says:--"On the habits of
the Orangs, as far as I have been able to observe them, I may remark
that they are as dull and slothful as can well be conceived, and on no
occasion, when pursuing them, did they move so fast as to preclude my
keeping pace with them easily through a moderately clear forest; and
even when obstructions below (such as wading up to the neck) allowed
them to get away some distance, they were sure to stop and allow me to
come up. I never observed the slightest attempt at defence, and the wood
which sometimes rattled about our ears was broken by their weight, and
not thrown, as some persons represent. If pushed to extremity, however,
the _Pappan_ could not be otherwise than formidable, and one unfortunate
man, who, with a party, was trying to catch a large one alive, lost two
of his fingers, besides being severely bitten on the face, whilst the
animal finally beat off his pursuers and escaped."
Mr. Wallace, on the other hand, affirms that he has several times
observed them throwing down branches when pursued. "It is true he does
not throw them at a person, but casts them down vertically; for it is
evident that a bough cannot be thrown to any distance from the top of a
lofty tree. In one case a female Mias, on a durian tree, kept up for at
least ten minutes a continuous shower of branches and of the heavy,
spined fruits, as large as 32-pounders, which most effectually kept us
clear of the tree she was on. She could be seen breaking them off and
throwing them down with every appearance of rage, uttering at intervals
a loud pumping grunt, and evidently meaning mischief."--"On the Habits
of the Orang-Utan," Annals of Nat. History, 1856. This statement, it
will be observed, is quite in accordance with that contained in the
letter of the Resident Palm quoted above (p. 16).
[23] On the Orang-Utan, or Mias of Borneo, Annals of Natural History,
1856.
[24] Notice of the external characters and habits of Troglodytes
Gorilla. Boston Journal of Natural History, 1847.
II
ON THE RELATIONS OF MAN TO THE
LOWER ANIMALS.
Multis videri poterit, majorem esse differentiam Simiæ et
Hominis, quam diei et noctis; verum tamen hi,
comparatione instituta inter summos Europæ Heroës et
Hottentottos ad Caput bonæ spei degentes, difficillime
sibi persuadebunt, has eosdem habere natales; vel si
virginem nobilem aulicam, maxime comtam et humanissimam,
conferre vellent cum homine sylvestri et sibi relicto,
vix augurari possent, hunc et illam ejusdem esse
speciei.--_Linnæi Amoenitates Acad. "Anthropomorpha."_
The question of questions for mankind--the problem which underlies all
others, and is more deeply interesting than any other--is the
ascertainment of the place which Man occupies in nature and of his
relations to the universe of things. Whence our race has come; what are
the limits of our power over nature, and of nature's power over us; to
what goal we are tending; are the problems which present themselves anew
and with undiminished interest to every man born into the world. Most of
us, shrinking from the difficulties and dangers which beset the seeker
after original answers to these riddles, are contented to ignore them
altogether, or to smother the investigating spirit under the featherbed
of respected and respectable tradition. But, in every age, one or two
restless spirits, blessed with that constructive genius, which can only
build on a secure foundation, or cursed with the mere spirit of
scepticism, are unable to follow in the well-worn and comfortable track
of their forefathers and contemporaries, and unmindful of thorns and
stumbling-blocks, strike out into paths of their own. The sceptics end
in the infidelity which asserts the problem to be insoluble, or in the
atheism which denies the existence of any orderly progress and
governance of things: the men of genius propound solutions which grow
into systems of Theology or of Philosophy, or veiled in musical language
which suggests more than it asserts, take the shape of the Poetry of an
epoch.
Each such answer to the great question, invariably asserted by the
followers of its propounder, if not by himself, to be complete and
final, remains in high authority and esteem, it may be for one century,
or it may be for twenty: but, as invariably, Time proves each reply to
have been a mere approximation to the truth--tolerable chiefly on
account of the ignorance of those by whom it was accepted, and wholly
intolerable when tested by the larger knowledge of their successors.
In a well-worn metaphor, a parallel is drawn between the life of man and
the metamorphosis of the caterpillar into the butterfly; but the
comparison may be more just as well as more novel, if for its former
term we take the mental progress of the race. History shows that the
human mind, fed by constant accessions of knowledge, periodically grows
too large for its theoretical coverings, and bursts them asunder to
appear in new habiliments, as the feeding and growing grub, at
intervals, casts its too narrow skin and assumes another, itself but
temporary. Truly the imago state of Man seems to be terribly distant,
but every moult is a step gained, and of such there have been many.
Since the revival of learning, whereby the Western races of Europe were
enabled to enter upon that progress towards true knowledge, which was
commenced by the philosophers of Greece, but was almost arrested in
subsequent long ages of intellectual stagnation, or, at most, gyration,
the human larva has been feeding vigorously, and moulting in proportion.
A skin of some dimension was cast in the 16th century, and another
towards the end of the 18th, while, within the last fifty years, the
extraordinary growth of every department of physical science has spread
among us mental food of so nutritious and stimulating a character that a
new ecdysis seems imminent. But this is a process not unusually
accompanied by many throes and some sickness and debility, or, it may
be, by graver disturbances; so that every good citizen must feel bound
to facilitate the process, and even if he have nothing but a scalpel to
work withal, to ease the cracking integument to the best of his ability.
In this duty lies my excuse for the publication of these essays. For it
will be admitted that some knowledge of man's position in the animate
world is an indispensable preliminary to the proper understanding of his
relations to the universe--and this again resolves itself, in the long
run, into an inquiry into the nature and the closeness of the ties which
connect him with those singular creatures whose history[25] has been
sketched in the preceding pages.
The importance of such an inquiry is indeed intuitively manifest.
Brought face to face with these blurred copies of himself, the least
thoughtful of men is conscious of a certain shock, due perhaps, not so
much to disgust at the aspect of what looks like an insulting
caricature, as to the awakening of a sudden and profound mistrust of
time-honoured theories and strongly-rooted prejudices regarding his own
position in nature, and his relations to the under-world of life; while
that which remains a dim suspicion for the unthinking, becomes a vast
argument, fraught with the deepest consequences, for all who are
acquainted with the recent progress of the anatomical and physiological
sciences.
I now propose briefly to unfold that argument, and to set forth, in a
form intelligible to those who possess no special acquaintance with
anatomical science, the chief facts upon which all conclusions
respecting the nature and the extent of the bonds which connect man with
the brute world must be based: I shall then indicate the one immediate
conclusion which, in my judgment, is justified by those facts, and I
shall finally discuss the bearing of that conclusion upon the hypotheses
which have been entertained respecting the Origin of Man.
The facts to which I would first direct the reader's attention, though
ignored by many of the professed instructors of the public mind, are
easy of demonstration and are universally agreed to by men of science;
while their significance is so great, that whoso has duly pondered over
them will, I think, find little to startle him in the other revelations
of Biology. I refer to those facts which have been made known by the
study of Development.
It is a truth of very wide, if not of universal, application, that every
living creature commences its existence under a form different from, and
simpler than, that which it eventually attains.
The oak is a more complex thing than the little rudimentary plant
contained in the acorn; the caterpillar is more complex than the egg;
the butterfly than the caterpillar; and each of these beings, in passing
from its rudimentary to its perfect condition, runs through a series of
changes, the sum of which is called its Development. In the higher
animals these changes are extremely complicated; but, within the last
half-century, the labours of such men as Von Baer, Rathke, Reichert,
Bischof, and Remak have almost completely unravelled them, so that the
successive stages of development which are exhibited by a Dog, for
example, are now as well known to the embryologist as are the steps of
the metamorphosis of the silkworm moth to the school-boy. It will be
useful to consider with attention the nature and the order of the stages
of canine development, as an example of the process in the higher
animals generally.
The Dog, like all animals, save the very lowest (and further inquiries
may not improbably remove the apparent exception), commences its
existence as an egg: as a body which is, in every sense, as much an egg
as that of a hen, but is devoid of that accumulation of nutritive matter
which confers upon the bird's egg its exceptional size and domestic
utility; and wants the shell, which would not only be useless to an
animal incubated within the body of its parent, but would cut it off
from access to the source of that nutriment which the young creature
requires, but which the minute egg of the mammal does not contain within
itself.
The Dog's egg is, in fact, a little spheroidal bag (Fig. 12), formed of
a delicate transparent membrane called the _vitelline membrane_, and
about 1/130 to 1/120th an inch in diameter. It contains a mass of viscid
nutritive matter--the "_yelk_"--within which is inclosed a second much
more delicate spheroidal bag, called the "_germinal vesicle_" (_a_). In
this, lastly, lies a more solid rounded body, termed the "_germinal
spot_" (_b_).
[Illustration: FIG. 12.--A. Egg of the Dog, with the vitelline membrane
burst, so as to give exit to the yelk, the germinal vesicle (_a_), and
its included spot (_b_). B. C. D. E. F. Successive changes of the yelk
indicated in the text. After Bischoff.]
The egg, or "Ovum," is originally formed within a gland, from which, in
due season, it becomes detached, and passes into the living chamber
fitted for its protection and maintenance during the protracted process
of gestation. Here, when subjected to the required conditions, this
minute and apparently insignificant particle of living matter becomes
animated by a new and mysterious activity. The germinal vesicle and spot
cease to be discernible (their precise fate being one of the yet
unsolved problems of embryology), but the yelk becomes circumferentially
indented, as if an invisible knife had been drawn round it, and thus
appears divided into two hemispheres (Fig. 12, C).
By the repetition of this process in various planes, these hemispheres
become subdivided, so that four segments are produced (D); and these, in
like manner, divide and subdivide again, until the whole yelk is
converted into a mass of granules, each of which consists of a minute
spheroid of yelk-substance, inclosing a central particle, the so-called
"_nucleus_" (F). Nature, by this process, has attained much the same
result as that at which a human artificer arrives by his operations in a
brickfield. She takes the rough plastic material of the yelk and breaks
it up into well-shaped, tolerably even-sized masses, handy for building
up into any part of the living edifice.
Next, the mass of organic bricks, or "_cells_" as they are technically
called, thus formed, acquires an orderly arrangement, becoming converted
into a hollow spheroid with double walls. Then, upon one side of this
spheroid, appears a thickening, and, by and bye, in the centre of the
area of thickening, a straight shallow groove (Fig. 13, A) marks the
central line of the edifice which is to be raised, or, in other words,
indicates the position of the middle line of the body of the future dog.
The substance bounding the groove on each side next rises up into a
fold, the rudiment of the side wall of that long cavity, which will
eventually lodge the spinal marrow and the brain; and in the floor of
this chamber appears a solid cellular cord, the so-called "_notochord_."
One end of the inclosed cavity dilates to form the head (Fig. 13, B),
the other remains narrow, and eventually becomes the tail; the side
walls of the body are fashioned out of the downward continuation of the
walls of the groove; and from them, by and bye, grow out little buds
which, by degrees, assume the shape of limbs. Watching the fashioning
process stage by stage, one is forcibly reminded of the modeller in
clay. Every part, every organ, is at first, as it were, pinched up
rudely, and sketched out in the rough; then shaped more accurately; and
only, at last, receives the touches which stamp its final character.
Thus, at length, the young puppy assumes such a form as is shown in Fig.
13, C. In this condition it has a disproportionately large head, as
dissimilar to that of a dog as the bud-like limbs are unlike his legs.
The remains of the yelk, which have not yet been applied to the
nutrition and growth of the young animal, are contained in a sac
attached to the rudimentary intestine, and termed the yelk-sac, or
"_umbilical vesicle_." Two membranous bags, intended to subserve
respectively the protection and nutrition of the young creature, have
been developed from the skin and from the under and hinder surface of
the body; the former, the so-called "_amnion_," is a sac filled with
fluid, which invests the whole body of the embryo, and plays the part of
a sort of water-bed for it; the other, termed the "_allantois_," grows
out, loaded with blood-vessels, from the ventral region, and eventually
applying itself to the walls of the cavity, in which the developing
organism is contained, enables these vessels to become the channel by
which the stream of nutriment, required to supply the wants of the
offspring, is furnished to it by the parent.
[Illustration: FIG. 13.--A. Earliest rudiment of the Dog. B. Rudiment
further advanced, showing the foundations of the head, tail, and
vertebral column. C. The very young puppy, with attached ends of the
yelk-sac and allantois, and invested in the amnion.]
The structure which is developed by the interlacement of the vessels of
the offspring with those of the parent, and by means of which the former
is enabled to receive nourishment and to get rid of effete matters, is
termed the "_Placenta_."
It would be tedious, and it is unnecessary for my present purpose, to
trace the process of development further; suffice it to say, that, by a
long and gradual series of changes, the rudiment here depicted and
described becomes a puppy, is born, and then, by still slower and less
perceptible steps, passes into the adult Dog.
There is not much apparent resemblance between a barndoor Fowl and the
Dog who protects the farm-yard. Nevertheless the student of development
finds, not only that the chick commences its existence as an egg,
primarily identical, in all essential respects, with that of the Dog,
but that the yelk of this egg undergoes division--that the primitive
groove arises, and that the contiguous parts of the germ are fashioned,
by precisely similar methods, into a young chick, which, at one stage of
its existence, is so like the nascent Dog, that ordinary inspection
would hardly distinguish the two.
* * * * *
The history of the development of any other vertebrate animal, Lizard,
Snake, Frog, or Fish, tells the same story. There is always, to begin
with, an egg having the same essential structure as that of the
Dog:--the yelk of that egg always undergoes division, or
"_segmentation_" as it is often called: the ultimate products of that
segmentation constitute the building materials for the body of the young
animal; and this is built up round a primitive groove, in the floor of
which a notochord is developed. Furthermore, there is a period in which
the young of all these animals resemble one another, not merely in
outward form, but in all essentials of structure, so closely, that the
differences between them are inconsiderable, while, in their subsequent
course, they diverge more and more widely from one another. And it is a
general law, that, the more closely any animals resemble one another in
adult structure, the longer and the more intimately do their embryos
resemble one another: so that, for example, the embryos of a Snake and
of a Lizard remain like one another longer than do those of a Snake and
of a Bird; and the embryo of a Dog and of a Cat remain like one another
for a far longer period than do those of a Dog and a Bird; or of a Dog
and an Opossum; or even than those of a Dog and a Monkey.
Thus the study of development affords a clear test of closeness of
structural affinity, and one turns with impatience to inquire what
results are yielded by the study of the development of Man. Is he
something apart? Does he originate in a totally different way from Dog,
Bird, Frog, and Fish, thus justifying those who assert him to have no
place in nature and no real affinity with the lower world of animal
life? Or does he originate in a similar germ, pass through the same slow
and gradually progressive modifications,--depend on the same
contrivances for protection and nutrition, and finally enter the world
by the help of the same mechanism? The reply is not doubtful for a
moment, and has not been doubtful any time these thirty years. Without
question, the mode of origin and the early stages of the development of
man are identical with those of the animals immediately below him in the
scale:--without a doubt, in these respects, he is far nearer the Apes,
than the Apes are to the Dog.
The Human ovum is about 1/125 of an inch in diameter, and might be
described in the same terms as that of the Dog, so that I need only
refer to the figure illustrative (14 A.) of its structure. It leaves the
organ in which it is formed in a similar fashion and enters the organic
chamber prepared for its reception in the same way, the conditions of
its development being in all respects the same. It has not yet been
possible (and only by some rare chance can it ever be possible) to study
the human ovum in so early a developmental stage as that of yelk
division, but there is every reason to conclude that the changes it
undergoes are identical with those exhibited by the ova of other
vertebrated animals; for the formative materials of which the
rudimentary human body is composed, in the earliest conditions in which
it has been observed, are the same as those of other animals. Some of
these earliest stages are figured below and, as will be seen, they are
strictly comparable to the very early states of the Dog; the marvellous
correspondence between the two which is kept up, even for some time, as
development advances, becoming apparent by the simple comparison of the
figures with those on page 58.
Indeed, it is very long before the body of the young human being can be
readily discriminated from that of the young puppy; but, at a tolerably
early period, the two become distinguishable by the different form of
their adjuncts, the yelk-sac and the allantois. The former, in the Dog,
becomes long and spindle-shaped, while in Man it remains spherical; the
latter, in the Dog, attains an extremely large size, and the vascular
processes which are developed from it and eventually give rise to the
formation of the placenta (taking root, as it were, in the parental
organism, so as to draw nourishment therefrom, as the root of a tree
extracts it from the soil) are arranged in an encircling zone, while in
Man, the allantois remains comparatively small, and its vascular
rootlets are eventually restricted to one disk-like spot. Hence, while
the placenta of the Dog is like a girdle, that of Man has the cake-like
form, indicated by the name of the organ.
[Illustration: FIG. 14.--A. Human ovum (after Kölliker). a. germinal
vesicle. b. germinal spot. B. A very early condition of Man, with
yelk-sac, allantois, and amnion (original). C. A more advanced stage
(after Kölliker), compare FIG. 13, C.]
But, exactly in those respects in which the developing Man differs from
the Dog, he resembles the ape, which, like man, has a spheroidal
yelk-sac and a discoidal--sometimes partially lobed--placenta.
So that it is only quite in the later stages of development that the
young human being presents marked differences from the young ape, while
the latter departs as much from the dog in its development, as the man
does.
Startling as the last assertion may appear to be, it is demonstrably
true, and it alone appears to me sufficient to place beyond all doubt
the structural unity of man with the rest of the animal world, and more
particularly and closely with the apes.
* * * * *
Thus, identical in the physical processes by which he
originates--identical in the early stages of his formation--identical in
the mode of his nutrition before and after birth, with the animals which
lie immediately below him in the scale--Man, if his adult and perfect
structure be compared with theirs, exhibits, as might be expected, a
marvellous likeness of organization. He resembles them as they resemble
one another--he differs from them as they differ from one another.--And,
though these differences and resemblances cannot be weighed and
measured, their value may be readily estimated; the scale or standard of
judgment, touching that value, being afforded and expressed by the
system of classification of animals now current among zoologists.
A careful study of the resemblances and differences presented by animals
has, in fact, led naturalists to arrange them into groups, or
assemblages, all the members of each group presenting a certain amount
of definable resemblance, and the number of points of similarity being
smaller as the group is larger and _vice versâ_. Thus, all creatures
which agree only in presenting the few distinctive marks of animality
form the "Kingdom" ANIMALIA. The numerous animals which agree only in
possessing the special characters of Vertebrates form one "Sub-kingdom"
of this Kingdom. Then the Sub-kingdom VERTEBRATA is subdivided into the
five "Classes," Fishes, Amphibians, Reptiles, Birds, and Mammals, and
these into smaller groups called "Orders"; these into "Families" and
"Genera"; while the last are finally broken up into the smallest
assemblages, which are distinguished by the possession of constant,
not-sexual, characters. These ultimate groups are Species.
Every year tends to bring about a greater uniformity of opinion
throughout the zoological world as to the limits and characters of these
groups, great and small. At present, for example, no one has the least
doubt regarding the characters of the classes Mammalia, Aves, or
Reptilia; nor does the question arise whether any thoroughly well-known
animal should be placed in one class or the other. Again, there is a
very general agreement respecting the characters and limits of the
orders of Mammals, and as to the animals which are structurally
necessitated to take a place in one or another order.
No one doubts, for example, that the Sloth and the Ant-eater, the
Kangaroo and the Opossum, the Tiger and the Badger, the Tapir and the
Rhinoceros, are respectively members of the same orders. These
successive pairs of animals may, and some do, differ from one another
immensely, in such matters as the proportions and structure of their
limbs; the number of their dorsal and lumbar vertebræ; the adaptation of
their frames to climbing, leaping, or running; the number and form of
their teeth; and the characters of their skulls and of the contained
brain. But, with all these differences, they are so closely connected in
all the more important and fundamental characters of their organization,
and so distinctly separated by these same characters from other animals,
that zoologists find it necessary to group them together as members of
one order. And if any new animal were discovered, and were found to
present no greater difference from the Kangaroo and the Opossum, for
example, than these animals do from one another, the zoologist would not
only be logically compelled to rank it in the same order with these, but
he would not think of doing otherwise.
Bearing this obvious course of zoological reasoning in mind, let us
endeavour for a moment to disconnect our thinking selves from the mask
of humanity; let us imagine ourselves scientific Saturnians, if you
will, fairly acquainted with such animals as now inhabit the Earth, and
employed in discussing the relations they bear to a new and singular
"erect and featherless biped," which some enterprising traveller,
overcoming the difficulties of space and gravitation, has brought from
that distant planet for our inspection, well preserved, may be, in a
cask of rum. We should all, at once, agree upon placing him among the
mammalian vertebrates; and his lower jaw, his molars, and his brain,
would leave no room for doubting the systematic position of the new
genus among those mammals, whose young are nourished during gestation by
means of a placenta, or what are called the "placental mammals."
Further, the most superficial study would at once convince us that,
among the orders of placental mammals, neither the Whales nor the hoofed
creatures, nor the Sloths and Ant-eaters, nor the carnivorous Cats,
Dogs, and Bears, still less the Rodent Rats and Rabbits, or the
Insectivorous Moles and Hedgehogs, or the Bats, could claim our "_Homo_"
as one of themselves.
There would remain then, but one order for comparison, that of the Apes
(using that word in its broadest sense), and the question for discussion
would narrow itself to this--is Man so different from any of these Apes
that he must form an order by himself? Or does he differ less from them
than they differ from one another, and hence must take his place in the
same order with them?
Being happily free from all real, or imaginary, personal interest in the
results of the inquiry thus set afoot, we should proceed to weigh the
arguments on one side and on the other, with as much judicial calmness
as if the question related to a new Opossum. We should endeavour to
ascertain, without seeking either to magnify or diminish them, all the
characters by which our new Mammal differed from the Apes; and if we
found that these were of less structural value, than those which
distinguish certain members of the Ape order from others universally
admitted to be of the same order, we should undoubtedly place the newly
discovered tellurian genus with them.
I now proceed to detail the facts which seem to me to leave us no
choice but to adopt the last mentioned course.
* * * * *
It is quite certain that the Ape which most nearly approaches man, in
the totality of its organization, is either the Chimpanzee or the
Gorilla; and as it makes no practical difference, for the purposes of my
present argument, which is selected for comparison, on the one hand,
with Man, and on the other hand, with the rest of the Primates,[26] I
shall select the latter (so far as its organization is known)--as a
brute now so celebrated in prose and verse, that all must have heard of
him, and have formed some conception of his appearance. I shall take up
as many of the most important points of difference between man and this
remarkable creature, as the space at my disposal will allow me to
discuss, and the necessities of the argument demand; and I shall inquire
into the value and magnitude of these differences, when placed side by
side with those which separate the Gorilla from other animals of the
same order.
In the general proportions of the body and limbs there is a remarkable
difference between the Gorilla and Man, which at once strikes the eye.
The Gorilla's brain-case is smaller, its trunk larger, its lower limbs
shorter, its upper limbs longer in proportion than those of Man.
I find that the vertebral column of a full-grown Gorilla, in the Museum
of the Royal College of Surgeons, measures 27 inches along its anterior
curvature, from the upper edge of the atlas, or first vertebra of the
neck, to the lower extremity of the sacrum; that the arm, without the
hand, is 31-1/2 inches long; that the leg, without the foot, is 26-1/2
inches long; that the hand is 9-3/4 inches long; the foot 11-1/4 inches
long.
In other words, taking the length of the spinal column as 100, the arm
equals 115, the leg 96, the hand 36, and the foot 41.
In the skeleton of a male Bosjesman, in the same collection, the
proportions, by the same measurement, to the spinal column, taken as
100, are--the arm 78, the leg 110, the hand 26, and the foot 32. In a
woman of the same race the arm is 83, and the leg 120, the hand and foot
remaining the same. In a European skeleton I find the arm to be 80, the
leg 117, the hand 26, the foot 35.
Thus the leg is not so different as it looks at first sight, in its
proportions to the spine in the Gorilla and in the Man--being very
slightly shorter than the spine in the former, and between 1/10 and 1/5
longer than the spine in the latter. The foot is longer and the hand
much longer in the Gorilla; but the great difference is caused by the
arms, which are very much longer than the spine in the Gorilla, very
much shorter than the spine in the Man.
The question now arises how are the other Apes related to the Gorilla in
these respects--taking the length of the spine, measured in the same
way, at 100. In an adult Chimpanzee, the arm is only 96, the leg 90, the
hand 43, the foot 39--so that the hand and the leg depart more from the
human proportion and the arm less, while the foot is about the same as
in the Gorilla.
In the Orang, the arms are very much longer than in the Gorilla (122),
while the legs are shorter (88); the foot is longer than the hand (52
and 48), and both are much longer in proportion to the spine.
In the other man-like Apes again, the Gibbons, these proportions are
still further altered; the length of the arms being to that of the
spinal column as 19 to 11; while the legs are also a third longer than
the spinal column, so as to be longer than in Man, instead of shorter.
The hand is half as long as the spinal column, and the foot, shorter
than the hand, is about 5/11ths of the length of the spinal column.
Thus _Hylobates_ is as much longer in the arms than the Gorilla, as the
Gorilla is longer in the arms than Man; while, on the other hand, it is
as much longer in the legs than the Man, as the Man is longer in the
legs than the Gorilla, so that it contains within itself the extremest
deviations from the average length of both pairs of limbs (see the
Frontispiece).
The Mandrill presents a middle condition, the arms and legs being nearly
equal in length, and both being shorter than the spinal column; while
hand and foot have nearly the same proportions to one another and to the
spine, as in Man.
In the Spider monkey (_Ateles_) the leg is longer than the spine, and
the arm than the leg; and, finally, in that remarkable Lemurine form,
the Indri (_Lichanotus_), the leg is about as long as the spinal column,
while the arm is not more than 11/18ths of its length; the hand having
rather less and the foot rather more, than one-third the length of the
spinal column.
These examples might be greatly multiplied, but they suffice to show
that, in whatever proportion of its limbs the Gorilla differs from Man,
the other Apes depart still more widely from the Gorilla, and that,
consequently, such differences of proportion can have no ordinal value.
* * * * *
We may next consider the differences presented by the trunk, consisting
of the vertebral column, or backbone, and the ribs and pelvis, or bony
hip-basin, which are connected with it, in Man and in the Gorilla
respectively.
In Man, in consequence partly of the disposition of the articular
surfaces of the vertebræ, and largely of the elastic tension of some of
the fibrous bands, or ligaments, which connect these vertebræ together,
the spinal column, as a whole, has an elegant S-like curvature, being
convex forwards in the neck, concave in the back, convex in the loins,
or lumbar region, and concave again in the sacral region; an arrangement
which gives much elasticity to the whole backbone, and diminishes the
jar communicated to the spine, and through it to the head, by locomotion
in the erect position.
Furthermore, under ordinary circumstances, Man has seven vertebræ in his
neck, which are called _cervical_; twelve succeed these, bearing ribs
and forming the upper part of the back, whence they are termed _dorsal_;
five lie in the loins, bearing no distinct, or free, ribs, and are
called _lumbar_; five, united together into a great bone, excavated in
front, solidly wedged in between the hip bones, to form the back of the
pelvis, and known by the name of the _sacrum_, succeed these; and
finally, three or four little more or less moveable bones, so small as
to be insignificant, constitute the _coccyx_ or rudimentary tail.
In the Gorilla, the vertebral column is similarly divided into cervical,
dorsal, lumbar, sacral and coccygeal vertebræ, and the total number of
cervical and dorsal vertebræ, taken together, is the same as in Man; but
the development of a pair of ribs to the first lumbar vertebra, which is
an exceptional occurrence in Man, is the rule in the Gorilla; and hence,
as lumbar are distinguished from dorsal vertebræ only by the presence or
absence of free ribs, the seventeen "dorso-lumbar" vertebræ of the
Gorilla are divided into thirteen dorsal and four lumbar, while in Man
they are twelve dorsal and five lumbar.
Not only, however, does Man occasionally possess thirteen pair of
ribs,[27] but the Gorilla sometimes has fourteen pairs, while an
Orang-Utan skeleton in the Museum of the Royal College of Surgeons has
twelve dorsal and five lumbar vertebræ, as in Man. Cuvier notes the same
number in a _Hylobates_. On the other hand, among the lower Apes, many
possess twelve dorsal and six or seven lumbar vertebræ; the Douroucouli
has fourteen dorsal and eight lumbar, and a Lemur (_Stenops
tardigradus_) has fifteen dorsal and nine lumbar vertebræ.
The vertebral column of the Gorilla, as a whole, differs from that of
Man in the less marked character of its curves, especially in the
slighter convexity of the lumbar region. Nevertheless, the curves are
present, and are quite obvious in young skeletons of the Gorilla and
Chimpanzee which have been prepared without removal of the ligaments. In
young Orangs similarly preserved, on the other hand, the spinal column
is either straight, or even concave forwards, throughout the lumbar
region.
Whether we take these characters then, or such minor ones as those which
are derivable from the proportional length of the spines of the
cervical vertebræ, and the like, there is no doubt whatsoever as to the
marked difference between Man and the Gorilla; but there is as little,
that equally marked differences, of the very same order, obtain between
the Gorilla and the lower apes.
[Illustration: FIG. 15.--Front and side views of the bony pelvis of Man,
the Gorilla and Gibbon: reduced from drawings made from nature, of the
same absolute length, by Mr. Waterhouse Hawkins.]
The Pelvis, or bony girdle of the hips, of Man is a strikingly human
part of his organization; the expanded haunch bones affording support
for his viscera during his habitually erect posture, and giving space
for the attachment of the great muscles which enable him to assume and
to preserve that attitude. In these respects the pelvis of the Gorilla
differs very considerably from his (Fig. 15). But go no lower than the
Gibbon, and see how vastly more he differs from the Gorilla than the
latter does from Man, even in this structure. Look at the flat, narrow
haunch bones--the long and narrow passage--the coarse, outwardly curved,
ischiatic prominences on which the Gibbon habitually rests, and which
are coated by the so-called "callosities," dense patches of skin, wholly
absent in the Gorilla, in the Chimpanzee, and in the Orang, as in Man!
In the lower Monkeys and in the Lemurs the difference becomes more
striking still, the pelvis acquiring an altogether quadrupedal
character.
But now let us turn to a nobler and more characteristic organ--that by
which the human frame seems to be, and indeed is, so strongly
distinguished from all others,--I mean the skull. The differences
between a Gorilla's skull and a Man's are truly immense (Fig. 16). In
the former, the face, formed largely by the massive jaw-bones,
predominates over the brain case, or cranium proper: in the latter, the
proportions of the two are reversed. In the Man, the occipital foramen,
through which passes the great nervous cord connecting the brain with
the nerves of the body, is placed just behind the centre of the base of
the skull, which thus becomes evenly balanced in the erect posture; in
the Gorilla, it lies in the posterior third of that base. In the Man,
the surface of the skull is comparatively smooth, and the supraciliary
ridges or brow prominences usually project but little--while, in the
Gorilla, vast crests are developed upon the skull, and the brow ridges
overhang the cavernous orbits, like great penthouses.
Sections of the skulls, however, show that some of the apparent defects
of the Gorilla's cranium arise, in fact, not so much from deficiency of
brain case as from excessive development of the parts of the face. The
cranial cavity is not ill-shaped, and the forehead is not truly
flattened or very retreating, its really well-formed curve being simply
disguised by the mass of bone which is built up against it (Fig. 16).
But the roofs of the orbits rise more obliquely into the cranial cavity,
thus diminishing the space for the lower part of the anterior lobes of
the brain, and the absolute capacity of the cranium is far less than
that of Man. So far as I am aware, no human cranium belonging to an
adult man has yet been observed with a less cubical capacity than 62
cubic inches, the smallest cranium observed in any race of men by
Morton, measuring 63 cubic inches; while, on the other hand, the most
capacious Gorilla skull yet measured has a content of not more than
34-1/2 cubic inches. Let us assume, for simplicity's sake, that the
lowest Man's skull has twice the capacity of that of the highest
Gorilla.[28]
No doubt, this is a very striking difference, but it loses much of its
apparent systematic value, when viewed by the light of certain other
equally indubitable facts respecting cranial capacities.
The first of these is, that the difference in the volume of the cranial
cavity of different races of mankind is far greater, absolutely, than
that between the lowest Man and the highest Ape, while, relatively, it
is about the same. For the largest human skull measured by Morton
contained 114 cubic inches, that is to say, had very nearly double the
capacity of the smallest; while its absolute preponderance, of 52 cubic
inches--is far greater than that by which the lowest adult male human
cranium surpasses the largest of the Gorillas (62-34-1/2 = 27-1/2).
Secondly, the adult crania of Gorillas which have as yet been measured
differ among themselves by nearly one-third, the maximum capacity being
34.5 cubic inches, the minimum 24 cubic inches; and, thirdly, after
making all due allowance for difference of size, the cranial capacities
of some of the lower Apes fall nearly as much, relatively, below those
of the higher Apes as the latter fall below Man.
Thus, even in the important matter of cranial capacity, Men differ more
widely from one another than they do from the Apes; while the lowest
Apes differ as much, in proportion, from the highest, as the latter does
from Man. The last proposition is still better illustrated by the study
of the modifications which other parts of the cranium undergo in the
Simian series.
It is the large proportional size of the facial bones and the great
projection of the jaws which confers upon the Gorilla's skull its small
facial angle and brutal character.
But if we consider the proportional size of the facial bones to the
skull proper only, the little _Chrysothrix_ (Fig. 16) differs very
widely from the Gorilla, and in the same way as Man does; while the
Baboons (_Cynocephalus_, Fig. 16) exaggerate the gross proportions of
the muzzle of the great Anthropoid, so that its visage looks mild and
human by comparison with theirs. The difference between the Gorilla
and the Baboon is even greater than it appears at first sight; for the
great facial mass of the former is largely due to a downward development
of the jaws; an essentially human character, superadded upon that almost
purely forward, essentially brutal, development of the same parts which
characterizes the Baboon, and yet more remarkably distinguishes the
Lemur.
[Illustration:
FIG. 16.--Sections of the skulls of Man and various Apes, drawn so as to
give the cerebral cavity the same length in each case, thereby
displaying the varying proportions of the facial bones. The line _b_
indicates the plane of the tentorium, which separates the cerebrum from
the cerebellum; _d_, the axis of the occipital outlet of the skull. The
extent of cerebral cavity behind _c_, which is a perpendicular erected
on _b_ at the point where the tentorium is attached posteriorly,
indicates the degree to which the cerebrum overlaps the cerebellum--the
space occupied by which is roughly indicated by the dark shading. In
comparing these diagrams, it must be recollected, that figures on so
small a scale as these simply exemplify the statements in the text, the
proof of which is to be found in the objects themselves.]
Similarly, the occipital foramen of _Mycetes_ (Fig. 16), and still more
of the Lemurs, is situated completely in the posterior face of the
skull, or as much further back than that of the Gorilla, as that of the
Gorilla is further back than that of Man; while, as if to render patent
the futility of the attempt to base any broad classificatory distinction
on such a character, the same group of Platyrhine, or American monkeys,
to which the _Mycetes_ belongs, contains the _Chrysothrix_, whose
occipital foramen is situated far more forward than in any other ape,
and nearly approaches the position it holds in Man.
Again, the Orang's skull is as devoid of excessively developed
supraciliary prominences as a Man's, though some varieties exhibit great
crests elsewhere (see p. 39); and in some of the Cebine Apes and in the
_Chrysothrix_, the cranium is as smooth and rounded as that of Man
himself.
What is true of these leading characteristics of the skull, holds good,
as may be imagined, of all minor features; so that for every constant
difference between the Gorilla's skull and the Man's, a similar constant
difference of the same order (that is to say, consisting in excess or
defect of the same quality) may be found between the Gorilla's skull and
that of some other ape. So that, for the skull, no less than for the
skeleton in general, the proposition holds good, that the differences
between Man and the Gorilla are of smaller value than those between the
Gorilla and some other Apes.
In connection with the skull, I may speak of the teeth--organs which
have a peculiar classificatory value, and whose resemblances and
differences of number, form, and succession, taken as a whole, are
usually regarded as more trustworthy indicators of affinity than any
others.
Man is provided with two sets of teeth--milk teeth and permanent teeth.
The former consist of four incisors, or cutting teeth; two canines, or
eye-teeth; and four molars, or grinders, in each jaw--making twenty in
all. The latter (Fig. 17) comprise four incisors, two canines, four
small grinders, called premolars or false molars, and six large
grinders, or true molars, in each jaw--making thirty-two in all. The
internal incisors are larger than the external pair, in the upper jaw,
smaller than the external pair, in the lower jaw. The crowns of the
upper molars exhibit four cusps, or blunt-pointed elevations, and a
ridge crosses the crown obliquely, from the inner, anterior, cusp to the
outer, posterior cusp (Fig. 17 _m^2_). The anterior lower molars have
five cusps, three external and two internal. The premolars have two
cusps, one internal and one external, of which the outer is the higher.
In all these respects the dentition of the Gorilla may be described in
the same terms as that of Man; but in other matters it exhibits many and
important differences (Fig. 17).
Thus the teeth of man constitute a regular and even series--without any
break and without any marked projection of one tooth above the level of
the rest; a peculiarity which, as Cuvier long ago showed, is shared by
no other mammal save one--as different a creature from man as can well
be imagined--namely, the long extinct _Anoplotherium_. The teeth of the
Gorilla, on the contrary, exhibit a break, or interval, termed the
_diastema_, in both jaws: in front of the eye-tooth, or between it and
the outer incisor, in the upper jaw; behind the eye-tooth, or between it
and the front false molar, in the lower jaw. Into this break in the
series, in each jaw, fits the canine of the opposite jaw; the size of
the eye-tooth in the Gorilla being so great that it projects, like a
tusk, far beyond the general level of the other teeth. The roots of the
false molar teeth of the Gorilla, again, are more complex than in Man,
and the proportional size of the molars is different. The Gorilla has
the crown of the hindmost grinder of the lower jaw more complex, and the
order of eruption of the permanent teeth is different; the permanent
canines making their appearance before the second and third molars in
Man, and after them in the Gorilla.
Thus, while the teeth of the Gorilla closely resemble those of Man in
number, kind, and in the general pattern of their crowns, they exhibit
marked differences from those of Man in secondary respects, such as
relative size, number of fangs, and order of appearance.
But, if the teeth of the Gorilla be compared with those of an Ape, no
further removed from it than a _Cynocephalus_, or Baboon, it will be
found that differences and resemblances of the same order are easily
observable; but that many of the points in which the Gorilla resembles
Man are those in which it differs from the Baboon; while various
respects in which it differs from Man are exaggerated in the
_Cynocephalus_. The number and the nature of the teeth remain the same
in the Baboon as in the Gorilla and in Man. But the pattern of the
Baboon's upper molars is quite different from that described above (Fig.
17), the canines are proportionally longer and more knife-like; the
anterior premolar in the lower jaw is specially modified; the posterior
molar of the lower jaw is still larger and more complex than in the
Gorilla.
Passing from the old-world Apes to those of the new world, we meet with
a change of much greater importance than any of these. In such a genus
as _Cebus_, for example (Fig. 17), it will be found that while in some
secondary points, such as the projection of the canines and the
diastema, the resemblance to the great ape is preserved; in other and
most important respects, the dentition is extremely different. Instead
of 20 teeth in the milk set, there are 24: instead of 32 teeth in the
permanent set, there are 36, the false molars being increased from eight
to twelve. And in form, the crowns of the molars are very unlike those
of the Gorilla, and differ far more widely from the human pattern.
[Illustration: FIG. 17.--Lateral views, of the same length, of the upper
jaws of various Primates. _i_, incisors; _c_, canines; _pm_, premolars;
_m_, molars. A line is drawn through the first molar of Man, Gorilla,
_Cynocephalus_, and _Cebus_, and the grinding surface of the second
molar is shown in each, its anterior and internal angle being just above
the _m_ of _m^2_.]
The Marmosets, on the other hand, exhibit the same number of teeth as
Man and the Gorilla; but, notwithstanding this, their dentition is very
different, for they have four more false molars, like the other
American monkeys--but as they have four fewer true molars, the total
remains the same. And passing from the American Apes to the Lemurs, the
dentition becomes still more completely and essentially different from
that of the Gorilla. The incisors begin to vary both in number and in
form. The molars acquire, more and more, a many-pointed, insectivorous
character, and in one Genus, the Aye-Aye (_Cheiromys_), the canines
disappear, and the teeth completely simulate those of a Rodent (Fig.
17).
Hence it is obvious that, greatly as the dentition of the highest Ape
differs from that of Man, it differs far more widely from that of the
lower and lowest Apes.
* * * * *
Whatever part of the animal fabric--whatever series of muscles, whatever
viscera might be selected for comparison--the result would be the
same--the lower Apes and the Gorilla would differ more than the Gorilla
and the Man. I cannot attempt in this place to follow out all these
comparisons in detail, and indeed it is unnecessary I should do so. But
certain real, or supposed, structural distinctions between man and the
apes remain, upon which so much stress has been laid, that they require
careful consideration, in order that the true value may be assigned to
those which are real, and the emptiness of those which are fictitious
may be exposed. I refer to the characters of the hand, the foot, and the
brain.
Man has been defined as the only animal possessed of two hands
terminating his fore-limbs, and of two feet ending his hind limbs, while
it has been said that all the apes possess four hands; and he has been
affirmed to differ fundamentally from all the apes in the characters of
his brain, which alone, it has been strangely asserted and re-asserted,
exhibits the structures known to anatomists as the posterior lobe, the
posterior cornu of the lateral ventricle, and the hippocampus minor.
That the former proposition should have gained general acceptance is not
surprising--indeed, at first sight, appearances are much in its favour:
but, as for the second, one can only admire the surpassing courage of
its enunciator, seeing that it is an innovation which is not only
opposed to generally and justly accepted doctrines, but which is
directly negatived by the testimony of all original inquirers, who have
specially investigated the matter: and that it neither has been, nor can
be, supported by a single anatomical preparation. It would, in fact, be
unworthy of serious refutation, except for the general and natural
belief that deliberate and reiterated assertions must have some
foundation.
* * * * *
Before we can discuss the first point with advantage we must consider
with some attention, and compare together, the structure of the human
hand and that of the human foot, so that we may have distinct and clear
ideas of what constitutes a hand and what a foot.
The external form of the human hand is familiar enough to every one. It
consists of a stout wrist followed by a broad palm, formed of flesh, and
tendons, and skin, binding together four bones, and dividing into four
long and flexible digits, or fingers, each of which bears on the back of
its last joint a broad and flattened nail. The longest cleft between any
two digits is rather less than half as long as the hand. From the outer
side of the base of the palm a stout digit goes off, having only two
joints instead of three; so short, that it only reaches to a little
beyond the middle of the first joint of the finger next it; and further
remarkable by its great mobility, in consequence of which it can be
directed outwards, almost at a right angle to the rest. This digit is
called the "_pollex_," or thumb; and, like the others, it bears a flat
nail upon the back of its terminal joint. In consequence of the
proportions and mobility of the thumb, it is what is termed "opposable";
in other words, its extremity can, with the greatest ease, be brought
into contact with the extremities of any of the fingers; a property upon
which the possibility of our carrying into effect the conceptions of the
mind so largely depends.
The external form of the foot differs widely from that of the hand; and
yet, when closely compared, the two present some singular resemblances.
Thus the ankle corresponds in a manner with the wrist; the sole with the
palm; the toes with the fingers; the great toe with the thumb. But the
toes, or digits of the foot, are far shorter in proportion than the
digits of the hand, and are less moveable, the want of mobility being
most striking in the great toe--which, again, is very much larger in
proportion to the other toes than the thumb to the fingers. In
considering this point, however, it must not be forgotten that the
civilized great toe, confined and cramped from childhood upwards, is
seen to a great disadvantage, and that in uncivilized and barefooted
people it retains a great amount of mobility, and even some sort of
opposability. The Chinese boatmen are said to be able to pull an oar,
the artisans of Bengal to weave, and the Carajas to steal fishhooks, by
its help; though, after all, it must be recollected that the structure
of its joints and the arrangement of its bones, necessarily render its
prehensile action far less perfect than that of the thumb.
But to gain a precise conception of the resemblances and differences of
the hand and foot, and of the distinctive characters of each, we must
look below the skin, and compare the bony framework and its motor
apparatus in each (Fig. 18).
The skeleton of the hand exhibits, in the region which we term the
wrist, and which is technically called the _carpus_--two rows of closely
fitted polygonal bones, four in each row, which are tolerably equal in
size. The bones of the first row with the bones of the forearm form the
wrist joint, and are arranged side by side, no one greatly exceeding or
over-lapping the rest.
The four bones of the second row of the carpus bear the four long bones
which support the palm of the hand. The fifth bone of the same character
is articulated in a much more free and moveable manner than the others,
with its carpal bone, and forms the base of the thumb. These are called
_metacarpal_ bones, and they carry the _phalanges_, or bones of the
digits, of which there are two in the thumb, and three in each of the
fingers.
[Illustration: FIG. 18.--The skeleton of the Hand and Foot of Man
reduced from Dr. Carter's drawings in Gray's "Anatomy." The hand is
drawn to a larger scale than the foot. The line _a a_ in the hand
indicates the boundary between the carpus and the metacarpus; _b b_ that
between the latter and the proximal phalanges; _c c_ marks the ends of
the distal phalanges. The line _a´ a´_ in the foot indicates the
boundary between the tarsus and metatarsus; _b´ b´_ marks that between
the metatarsus and the proximal phalanges; and _c´ c´_ bounds the ends
of the distal phalanges; _ca_, the calcaneum; _as_, the astragalus;
_sc_, the scaphoid bone in the tarsus.]
The skeleton of the foot is very like that of the hand in some respects.
Thus there are three phalanges in each of the lesser toes, and only two
in the great toe, which answers to the thumb. There is a long bone,
termed _metatarsal_, answering to the metacarpal, for each digit; and
the _tarsus_, which corresponds with the carpus, presents four short
polygonal bones in a row, which correspond very closely with the four
carpal bones of the second row of the hand. In other respects the foot
differs very widely from the hand. Thus the great toe is the longest
digit but one; and its metatarsal is far less moveably articulated with
the tarsus, than the metacarpal of the thumb with the carpus. But a far
more important distinction lies in the fact that, instead of four more
tarsal bones there are only three; and that these three are not arranged
side by side, or in one row. One of them, the _os calcis_ or heel bone
(_ca_), lies externally, and sends back the large projecting heel;
another, the _astragalus_ (_as_), rests on this by one face, and by
another, forms, with the bones of the leg, the ankle joint; while a
third face, directed forwards, is separated from the three inner tarsal
bones of the row next the metatarsus by a bone called the _scaphoid_
(_sc_).
Thus there is a fundamental difference in the structure of the foot and
the hand, observable when the carpus and the tarsus are contrasted; and
there are differences of degree noticeable when the proportions and the
mobility of the metacarpals and metatarsals, with their respective
digits, are compared together.
The same two classes of differences become obvious when the muscles of
the hand are compared with those of the foot.
Three principal sets of muscles, called "flexors," bend the fingers and
thumb, as in clenching the fist, and three sets--the extensors--extend
them, as in straightening the fingers. These muscles are all "long
muscles"; that is to say, the fleshy part of each, lying in and being
fixed to the bones of the arm, is, at the other end, continued into
tendons, or rounded cords, which pass into the hand, and are ultimately
fixed to the bones which are to be moved. Thus, when the fingers are
bent, the fleshy parts of the flexors of the fingers, placed in the arm,
contract, in virtue of their peculiar endowment as muscles; and pulling
the tendinous cords, connected with their ends, cause them to pull down
the bones of the fingers towards the palm.
Not only are the principal flexors of the fingers and of the thumb long
muscles, but they remain quite distinct from one another throughout
their whole length.
In the foot, there are also three principal flexor muscles of the digits
or toes, and three principal extensors; but one extensor and one flexor
are short muscles; that is to say, their fleshy parts are not situated
in the leg (which corresponds with the arm), but in the back and in the
sole of the foot--regions which correspond with the back and the palm of
the hand.
Again, the tendons of the long flexor of the toes, and of the long
flexor of the great toe, when they reach the sole of the foot, do not
remain distinct from one another, as the flexors in the palm of the hand
do, but they become united and commingled in a very curious
manner--while their united tendons receive an accessory muscle connected
with the heel-bone.
But perhaps the most absolutely distinctive character about the muscles
of the foot is the existence of what is termed the _peronæus longus_, a
long muscle fixed to the outer bone of the leg, and sending its tendon
to the outer ankle, behind and below which it passes, and then crosses
the foot obliquely to be attached to the base of the great toe. No
muscle in the hand exactly corresponds with this, which is eminently a
foot muscle.
To resume--the foot of man is distinguished from his hand by the
following absolute anatomical differences:--
1. By the arrangement of the tarsal bones.
2. By having a short flexor and a short extensor muscle of the digits.
3. By possessing the muscle termed _peronæus longus_.
And if we desire to ascertain whether the terminal division of a limb,
in other Primates, is to be called a foot or a hand, it is by the
presence or absence of these characters that we must be guided, and not
by the mere proportions and greater or lesser mobility of the great toe,
which may vary indefinitely without any fundamental alteration in the
structure of the foot.
* * * * *
Keeping these considerations in mind, let us now turn to the limbs of
the Gorilla. The terminal division of the fore-limb presents no
difficulty--bone for bone and muscle for muscle, are found to be
arranged essentially as in man, or with such minor differences as are
found as varieties in man. The Gorilla's hand is clumsier, heavier, and
has a thumb somewhat shorter in proportion than that of man; but no one
has ever doubted its being a true hand.
At first sight, the termination of the hind limb of the Gorilla looks
very hand-like, and as it is still more so in many of the lower apes,
it is not wonderful that the appellation "Quadrumana," or four-handed
creatures, adopted from the older anatomists[29] by Blumenbach, and
unfortunately rendered current by Cuvier, should have gained such wide
acceptance as a name for the Simian group. But the most cursory
anatomical investigation at once proves that the resemblance of the
so-called "hind hand" to a true hand, is only skin deep, and that, in
all essential respects, the hind limb of the Gorilla is as truly
terminated by a foot as that of man. The tarsal bones, in all important
circumstances of number, disposition, and form, resemble those of man
(Fig. 19). The metatarsals and digits, on the other hand, are
proportionally longer and more slender, while the great toe is not only
proportionally shorter and weaker, but its metatarsal bone is united by
a more moveable joint with the tarsus. At the same time, the foot is set
more obliquely upon the leg than in man.
As to the muscles, there is a short flexor, a short extensor, and a
_peronæus longus_, while the tendons of the long flexors of the great
toe and of the other toes are united together and with an accessory
fleshy bundle.
The hind limb of the Gorilla, therefore, ends in a true foot, with a
very moveable great toe. It is a prehensile foot, indeed, but is in no
sense a hand: it is a foot which differs from that of man not in any
fundamental character, but in mere proportions, in the degree of
mobility, and in the secondary arrangement of its parts.
It must not be supposed, however, because I speak of these differences
as not fundamental, that I wish to underrate their value. They are
important enough in their way, the structure of the foot being in strict
correlation with that of the rest of the organism in each case. Nor can
it be doubted that the greater division of physiological labour in Man,
so that the function of support is thrown wholly on the leg and foot, is
an advance in organization of very great moment to him; but, after all,
regarded anatomically, the resemblances between the foot of Man and the
foot of the Gorilla are far more striking and important than the
differences.
[Illustration: FIG. 19.--Foot of Man, Gorilla, and Orang-Utan of the
same absolute length, to show the differences in proportion of each.
Letters as in Fig. 18. Reduced from original drawings by Mr. Waterhouse
Hawkins.]
I have dwelt upon this point at length, because it is one regarding
which much delusion prevails; but I might have passed it over without
detriment to my argument, which only requires me to show that, be the
differences between the hand and foot of Man and those of the Gorilla
what they may--the differences between those of the Gorilla and those
of the lower Apes are much greater.
It is not necessary to descend lower in the scale than the Orang for
conclusive evidence on this head.
The thumb of the Orang differs more from that of the Gorilla than the
thumb of the Gorilla differs from that of Man, not only by its
shortness, but by the absence of any special long flexor muscle. The
carpus of the Orang, like that of most lower apes, contains nine bones,
while in the Gorilla, as in Man and the Chimpanzee, there are only
eight.
The Orang's foot (Fig. 19) is still more aberrant; its very long toes
and short tarsus, short great toe, short and raised heel, great
obliquity of articulation in the leg, and absence of a long flexor
tendon to the great toe, separating it far more widely from the foot of
the Gorilla than the latter is separated from that of Man.
But, in some of the lower apes, the hand and foot diverge still more
from those of the Gorilla, than they do in the Orang. The thumb ceases
to be opposable in the American monkeys; is reduced to a mere rudiment
covered by the skin in the Spider Monkey; and is directed forwards and
armed with a curved claw like the other digits, in the Marmosets--so
that, in all these cases, there can be no doubt but that the hand is
more different from that of the Gorilla than the Gorilla's hand is from
Man's.
And as to the foot, the great toe of the Marmoset is still more
insignificant in proportion than that of the Orang--while in the Lemurs
it is very large, and as completely thumb-like and opposable as in the
Gorilla--but in these animals the second toe is often irregularly
modified, and in some species the two principal bones of the tarsus, the
_astragalus_ and the _os calcis_, are so immensely elongated as to
render the foot, so far, totally unlike that of any other mammal.
So with regard to the muscles. The short flexor of the toes of the
Gorilla differs from that of Man by the circumstance that one slip of
the muscle is attached, not to the heel bone, but to the tendons of the
long flexors. The lower Apes depart from the Gorilla by an exaggeration
of the same character, two, three, or more, slips becoming fixed to the
long flexor tendons--or by a multiplication of the slips.--Again, the
Gorilla differs slightly from Man in the mode of interlacing of the long
flexor tendons: and the lower apes differ from the Gorilla in exhibiting
yet other, sometimes very complex, arrangements of the same parts, and
occasionally in the absence of the accessory fleshy bundle.
Throughout all these modifications it must be recollected that the foot
loses no one of its essential characters. Every Monkey and Lemur
exhibits the characteristic arrangement of tarsal bones, possesses a
short flexor and short extensor muscle, and a _peronæus longus_. Varied
as the proportions and appearance of the organ may be, the terminal
division of the hind limb remains, in plan and principle of
construction, a foot, and never, in those respects, can be confounded
with a hand.
Hardly any part of the bodily frame, then, could be found better
calculated to illustrate the truth that the structural differences
between Man and the highest Ape are of less value than those between the
highest and the lower Apes, than the hand or the foot, and yet, perhaps,
there is one organ the study of which enforces the same conclusion in a
still more striking manner--and that is the Brain.
But before entering upon the precise question of the amount of
difference between the Ape's brain and that of Man, it is necessary that
we should clearly understand what constitutes a great, and what a small
difference in cerebral structure; and we shall be best enabled to do
this by a brief study of the chief modifications which the brain
exhibits in the series of vertebrate animals.
The brain of a fish is very small, compared with the spinal cord into
which it is continued, and with the nerves which come off from it: of
the segments of which it is composed--the olfactory lobes, the cerebral
hemisphere, and the succeeding divisions--no one predominates so much
over the rest as to obscure or cover them; and the so-called optic lobes
are, frequently, the largest masses of all. In Reptiles, the mass of the
brain, relatively to the spinal cord, increases and the cerebral
hemispheres begin to predominate over the other parts; while in Birds
this predominance is still more marked. The brain of the lowest Mammals,
such as the duck-billed Platypus and the Opossums and Kangaroos,
exhibits a still more definite advance in the same direction. The
cerebral hemispheres have now so much increased in size as, more or
less, to hide the representatives of the optic lobes, which remain
comparatively small, so that the brain of a Marsupial is extremely
different from that of a Bird, Reptile, or Fish. A step higher in the
scale, among the placental Mammals, the structure of the brain acquires
a vast modification--not that it appears much altered externally, in a
Rat or in a Rabbit, from what it is in a Marsupial--nor that the
proportions of its parts are much changed, but an apparently new
structure is found between the cerebral hemispheres, connecting them
together, as what is called the "great commissure" or "corpus callosum."
The subject requires careful re-investigation, but if the currently
received statements are correct, the appearance of the "corpus callosum"
in the placental mammals is the greatest and most sudden modification
exhibited by the brain in the whole series of vertebrated animals--it is
the greatest leap anywhere made by Nature in her brain work. For the two
halves of the brain being once thus knit together, the progress of
cerebral complexity is traceable through a complete series of steps from
the lowest Rodent, or Insectivore, to Man; and that complexity consists,
chiefly, in the disproportionate development of the cerebral hemispheres
and of the cerebellum, but especially of the former, in respect to the
other parts of the brain.
In the lower placental mammals, the cerebral hemispheres leave the
proper upper and posterior face of the cerebellum completely visible,
when the brain is viewed from above, but, in the higher forms, the
hinder part of each hemisphere, separated only by the tentorium (p. 92)
from the anterior face of the cerebellum, inclines backwards and
downwards, and grows out, as the so-called "posterior lobe," so as at
length to overlap and hide the cerebellum. In all Mammals, each cerebral
hemisphere contains a cavity which is termed the "ventricle," and as
this ventricle is prolonged, on the one hand, forwards, and on the other
downwards, into the substance of the hemisphere, it is said to have two
horns or "cornua," an "anterior cornu," and a "descending cornu." When
the posterior lobe is well developed, a third prolongation of the
ventricular cavity extends into it, and is called the "posterior cornu."
In the lower and smaller forms of placental Mammals the surface of the
cerebral hemispheres is either smooth or evenly rounded, or exhibits a
very few grooves, which are technically termed "sulci," separating
ridges or "convolutions" of the substance of the brain; and the smaller
species of all orders tend to a similar smoothness of brain. But, in the
higher orders, and especially the larger members of these orders, the
grooves, or sulci, become extremely numerous, and the intermediate
convolutions proportionately more complicated in their meanderings,
until, in the Elephant, the Porpoise, the higher Apes, and Man, the
cerebral surface appears a perfect labyrinth of tortuous foldings.
Where a posterior lobe exists and presents its customary cavity--the
posterior cornu--it commonly happens that a particular sulcus appears
upon the inner and under surface of the lobe, parallel with and beneath
the floor of the cornu--which is, as it were, arched over the roof of
the sulcus. It is as if the groove had been formed by indenting the
floor of the posterior horn from without with a blunt instrument, so
that the floor should rise as a convex eminence. Now this eminence is
what has been termed the "Hippocampus minor"; the "Hippocampus major"
being a larger eminence in the floor of the descending cornu. What may
be the functional importance of either of these structures we know not.
* * * * *
As if to demonstrate, by a striking example, the impossibility of
erecting any cerebral barrier between man and the apes, Nature has
provided us, in the latter animals, with an almost complete series of
gradations from brains little higher than that of a Rodent, to brains
little lower than that of Man. And it is a remarkable circumstance that
though, so far as our present knowledge extends, there _is_ one true
structural break in the series of forms of Simian brains, this hiatus
does not lie between Man and the man-like Apes, but between the lower
and the lowest Simians; or, in other words, between the old and new
world apes and monkeys, and the Lemurs. Every Lemur which has yet been
examined, in fact, has its cerebellum partially visible from above, and
its posterior lobe, with the contained posterior cornu and hippocampus
minor, more or less rudimentary. Every Marmoset, American monkey, old
world monkey, Baboon, or Man-like ape, on the contrary, has its
cerebellum entirely hidden, posteriorly, by the cerebral lobes, and
possesses a large posterior cornu, with a well-developed hippocampus
minor.
* * * * *
In many of these creatures, such as the Saimiri (_Chrysothrix_), the
cerebral lobes overlap and extend much further behind the cerebellum, in
proportion, than they do in man (Fig. 16)--and it is quite certain that,
in all, the cerebellum is completely covered behind, by well-developed
posterior lobes. The fact can be verified by every one who possesses the
skull of any old or new world monkey. For, inasmuch as the brain in all
mammals completely fills the cranial cavity, it is obvious that a cast
of the interior of the skull will reproduce the general form of the
brain, at any rate with such minute and, for the present purpose,
utterly unimportant differences as may result from the absence of the
enveloping membranes of the brain in the dry skull. But if such a cast
be made in plaster, and compared with a similar cast of the interior of
a human skull, it will be obvious that the cast of the cerebral chamber,
representing the cerebrum of the ape, as completely covers over and
overlaps the cast of the cerebellar chamber, representing the
cerebellum, as it does in the man (Fig. 20). A careless observer,
forgetting that a soft structure like the brain loses its proper shape
the moment it is taken out of the skull, may indeed mistake the
uncovered condition of the cerebellum of an extracted and distorted
brain for the natural relations of the parts; but his error must become
patent even to himself if he try to replace the brain within the
cranial chamber. To suppose that the cerebellum of an ape is naturally
uncovered behind is a miscomprehension comparable only to that of one
who should imagine that a man's lungs always occupy but a small portion
of the thoracic cavity--because they do so when the chest is opened, and
their elasticity is no longer neutralized by the pressure of the air.
[Illustration: FIG. 20.--Drawings of the internal casts of a Man's and
of a Chimpanzee's skull, of the same absolute length, and placed in
corresponding positions, _A._ Cerebrum; _B._ Cerebellum. The former
drawing is taken from a cast in the Museum of the Royal College of
Surgeons, the latter from the photograph of the cast of a Chimpanzee's
skull, which illustrates the paper by Mr. Marshall "On the Brain of the
Chimpanzee" in the Natural History Review for July, 1861. The sharper
definition of the lower edge of the cast of the cerebral chamber in the
Chimpanzee arises from the circumstance that the tentorium remained in
that skull and not in the Man's. The cast more accurately represents the
brain in Chimpanzee than in the Man; and the great backward projection
of the posterior lobes of the cerebrum of the former, beyond the
cerebellum, is conspicuous.]
And the error is the less excusable, as it must become apparent to every
one who examines a section of the skull of any ape above a Lemur,
without taking the trouble to make a cast of it. For there is a very
marked groove in every such skull, as in the human skull--which
indicates the line of attachment of what is termed the _tentorium_--a
sort of parchment-like shelf, or partition, which, in the recent state,
is interposed between the cerebrum and cerebellum, and prevents the
former from pressing upon the latter (see Fig. 16).
This groove, therefore, indicates the line of separation between that
part of the cranial cavity which contains the cerebrum, and that which
contains the cerebellum; and as the brain exactly fills the cavity of
the skull, it is obvious that the relations of these two parts of the
cranial cavity at once informs us of the relations of their contents.
Now in man, in all the old world, and in all the new world Simiæ, with
one exception, when the face is directed forwards, this line of
attachment of the tentorium, or impression for the lateral sinus, as it
is technically called, is nearly horizontal, and the cerebral chamber
invariably overlaps or projects behind the cerebellar chamber. In the
Howler Monkey or _Mycetes_ (see Fig. 16), the line passes obliquely
upwards and backwards, and the cerebral overlap is almost nil; while in
the Lemurs, as in the lower mammals, the line is much more inclined in
the same direction, and the cerebellar chamber projects considerably
beyond the cerebral.
When the gravest errors respecting points so easily settled as this
question respecting the posterior lobes can be authoritatively
propounded, it is no wonder that matters of observation, of no very
complex character, but still requiring a certain amount of care, should
have fared worse. Any one who cannot see the posterior lobe in an ape's
brain is not likely to give a very valuable opinion respecting the
posterior cornu or the hippocampus minor. If a man cannot see a church,
it is preposterous to take his opinion about its altar-piece or painted
window--so that I do not feel bound to enter upon any discussion of
these points, but content myself with assuring the reader that the
posterior cornu and the hippocampus minor, have now been seen--usually,
at least as well developed as in man, and often better--not only in the
Chimpanzee, the Orang, and the Gibbon, but in all the genera of the old
world baboons and monkeys, and in most of the new world forms, including
the Marmosets.[30]
In fact, all the abundant and trustworthy evidence (consisting of the
results of careful investigations directed to the determination of these
very questions, by skilled anatomists) which we now possess, leads to
the conviction that, so far from the posterior lobe, the posterior
cornu, and the hippocampus minor, being structures peculiar to and
characteristic of man, as they have been over and over again asserted to
be, even after the publication of the clearest demonstration of the
reverse, it is precisely these structures which are the most marked
cerebral characters common to man with the apes. They are among the most
distinctly Simian peculiarities which the human organism exhibits.
As to the convolutions, the brains of the apes exhibit every stage of
progress, from the almost smooth brain of the Marmoset, to the Orang and
the Chimpanzee, which fall but little below Man. And it is most
remarkable that, as soon as all the principal sulci appear, the pattern
according to which they are arranged is identical with that of the
corresponding sulci of man. The surface of the brain of a monkey
exhibits a sort of skeleton map of man's, and in the man-like Apes the
details become more and more filled in, until it is only in minor
characters, such as the greater excavation of the anterior lobes, the
constant presence of fissures usually absent in man, and the different
disposition and proportions of some convolutions, that the
Chimpanzee's or the Orang's brain can be structurally distinguished from
Man's.
[Illustration: FIG. 21.--Drawings of the cerebral hemispheres of a Man
and of a Chimpanzee of the same length, in order to show the relative
proportions of the parts: the former taken from a specimen, which Mr.
Flower, Conservator of the Museum of the Royal College of Surgeons, was
good enough to dissect for me; the latter, from the photograph of a
similarly dissected Chimpanzee's brain, given in Mr. Marshall's paper
above referred to. _a_, posterior lobe; _b_, lateral ventricle; _c_,
posterior cornu; _x_, the hippocampus minor.]
So far as cerebral structure goes, therefore, it is clear that Man
differs less from the Chimpanzee or the Orang, than these do even from
the Monkeys, and that the difference between the brains of the
Chimpanzee and of Man is almost insignificant, when compared with that
between the Chimpanzee brain and that of a Lemur.
It must not be overlooked, however, that there is a very striking
difference in the absolute mass and weight between the lowest human
brain and that of the highest ape--a difference which is all the more
remarkable when we recollect that a full grown Gorilla is probably
pretty nearly twice as heavy as a Bosjes man, or as many an European
woman. It may be doubted whether a healthy human adult brain ever
weighed less than thirty-one or two ounces, or that the heaviest Gorilla
brain has exceeded twenty ounces.
This is a very noteworthy circumstance, and doubtless will one day help
to furnish an explanation of the great gulf which intervenes between the
lowest man and the highest ape in intellectual power;[31] but it has
little systematic value, for the simple reason that, as may be
concluded from what has been already said respecting cranial capacity,
the difference in weight of brain between the highest and the lowest men
is far greater, both relatively and absolutely, than that between the
lowest man and the highest ape. The latter, as has been seen, is
represented by, say twelve, ounces of cerebral substance absolutely, or
by 32: 20 relatively; but as the largest recorded human brain weighed
between 65 and 66 ounces, the former difference is represented by more
than 33 ounces absolutely, or by 65: 32 relatively. Regarded
systematically the cerebral differences, of man and apes, are not of
more than generic value--his Family distinction resting chiefly on his
dentition, his pelvis, and his lower limbs.
* * * * *
Thus, whatever system of organs be studied, the comparison of their
modifications in the ape series leads to one and the same result--that
the structural differences which separate Man from the Gorilla and the
Chimpanzee are not so great as those which separate the Gorilla from the
lower apes.
But in enunciating this important truth I must guard myself against a
form of misunderstanding, which is very prevalent. I find, in fact, that
those who endeavour to teach what nature so clearly shows us in this
matter, are liable to have their opinions misrepresented and their
phraseology garbled, until they seem to say that the structural
differences between man and even the highest apes are small and
insignificant. Let me take this opportunity then of distinctly
asserting, on the contrary, that they are great and significant; that
every bone of a Gorilla bears marks by which it might be distinguished
from the corresponding bone of a Man; and that, in the present creation,
at any rate, no intermediate link bridges over the gap between _Homo_
and _Troglodytes_.
It would be no less wrong than absurd to deny the existence of this
chasm; but it is at least equally wrong and absurd to exaggerate its
magnitude, and, resting on the admitted fact of its existence, to refuse
to inquire whether it is wide or narrow. Remember, if you will, that
there is no existing link between Man and the Gorilla, but do not forget
that there is a no less sharp line of demarcation, a no less complete
absence of any transitional form, between the Gorilla and the Orang, or
the Orang and the Gibbon. I say, not less sharp, though it is somewhat
narrower. The structural differences between Man and the Man-like Apes
certainly justify our regarding him as constituting a family apart from
them; though, inasmuch as he differs less from them than they do from
other families of the same order, there can be no justification for
placing him in a distinct order.
And thus the sagacious foresight of the great lawgiver of systematic
zoology, Linnæus, becomes justified, and a century of anatomical
research brings us back to his conclusion, that man is a member of the
same order (for which the Linnæan term PRIMATES ought to be retained) as
the Apes and Lemurs. This order is now divisible into seven families, of
about equal systematic value: the first, the ANTHROPINI, contains Man
alone; the second, the CATARHINI, embraces the old world apes; the
third, the PLATYRHINI, all new world apes, except the Marmosets; the
fourth, the ARCTOPITHECINI, contains the Marmosets; the fifth, the
LEMURINI, the Lemurs--from which _Cheiromys_ should probably be excluded
to form a sixth distinct family, the CHEIROMYINI; while the seventh, the
GALEOPITHECINI, contains only the flying Lemur _Galeopithecus_,--a
strange form which almost touches on the Bats, as the _Cheiromys_ puts
on a rodent clothing, and the Lemurs simulate Insectivora.
Perhaps no order of mammals presents us with so extraordinary a series
of gradations as this--leading us insensibly from the crown and summit
of the animal creation down to creatures, from which there is but a
step, as it seems, to the lowest, smallest, and least intelligent of the
placental Mammalia. It is as if nature herself had foreseen the
arrogance of man, and with Roman severity had provided that his
intellect, by its very triumphs, should call into prominence the slaves,
admonishing the conqueror that he is but dust.
* * * * *
These are the chief facts, this the immediate conclusion from them to
which I adverted in the commencement of this Essay. The facts, I
believe, cannot be disputed; and if so, the conclusion appears to me to
be inevitable.
But if Man be separated by no greater structural barrier from the brutes
than they are from one another--then it seems to follow that if any
process of physical causation can be discovered by which the genera and
families of ordinary animals have been produced, that process of
causation is amply sufficient to account for the origin of Man. In other
words, if it could be shown that the Marmosets, for example, have arisen
by gradual modification of the ordinary Platyrhini, or that both
Marmosets and Platyrhini are modified ramifications of a primitive
stock--then, there would be no rational ground for doubting that man
might have originated, in the one case, by the gradual modification of a
man-like ape; or, in the othercase, as a ramification of the same
primitive stock as those apes.
At the present moment, but one such process of physical causation has
any evidence in its favour; or, in other words, there is but one
hypothesis regarding the origin of species of animals in general which
has any scientific existence--that propounded by Mr. Darwin. For
Lamarck, sagacious as many of his views were, mingled them with so much
that was crude and even absurd, as to neutralize the benefit which his
originality might have effected, had he been a more sober and cautious
thinker; and though I have heard of the announcement of a formula
touching "the ordained continuous becoming of organic forms," it is
obvious that it is the first duty of a hypothesis to be intelligible,
and that a qua-quâ-versal proposition of this kind, which may be read
backwards, or forwards, or sideways, with exactly the same amount of
signification, does not really exist, though it may seem to do so.
At the present moment, therefore, the question of the relation of man to
the lower animals resolves itself, in the end, into the larger question
of the tenability or untenability of Mr. Darwin's views. But here we
enter upon difficult ground, and it behoves us to define our exact
position with the greatest care.
It cannot be doubted, I think, that Mr. Darwin has satisfactorily proved
that what he terms selection, or selective modification, must occur, and
does occur, in nature; and he has also proved to superfluity that such
selection is competent to produce forms as distinct, structurally, as
some genera even are. If the animated world presented us with none but
structural differences, I should have no hesitation in saying that Mr.
Darwin had demonstrated the existence of a true physical cause, amply
competent to account for the origin of living species, and of man among
the rest.
But, in addition to their structural distinctions, the species of
animals and plants, or at least a great number of them, exhibit
physiological characters--what are known as distinct species,
structurally, being for the most part either altogether incompetent to
breed one with another; or if they breed, the resulting mule, or hybrid,
is unable to perpetuate its race with another hybrid of the same kind.
A true physical cause is, however, admitted to be such only on one
condition--that it shall account for all the phenomena which come within
the range of its operation. If it is inconsistent with any one
phenomenon, it must be rejected; if it fails to explain any one
phenomenon, it is so far weak, so far to be suspected; though it may
have a perfect right to claim provisional acceptance.
Now, Mr. Darwin's hypothesis is not, so far as I am aware, inconsistent
with any known biological fact; on the contrary, if admitted, the facts
of Development, of Comparative Anatomy, of Geographical Distribution,
and of Palæontology, become connected together, and exhibit a meaning
such as they never possessed before; and I, for one, am fully convinced,
that if not precisely true, that hypothesis is as near an approximation
to the truth as, for example, the Copernican hypothesis was to the true
theory of the planetary motions.
But, for all this, our acceptance of the Darwinian hypothesis must be
provisional so long as one link in the chain of evidence is wanting; and
so long as all the animals and plants certainly produced by selective
breeding from a common stock are fertile, and their progeny are fertile
with one another, that link will be wanting. For, so long, selective
breeding will not be proved to be competent to do all that is required
of it to produce natural species.
I have put this conclusion as strongly as possible before the reader,
because the last position in which I wish to find myself is that of an
advocate for Mr. Darwin's, or any other views--if by an advocate is
meant one whose business it is to smooth over real difficulties, and to
persuade where he cannot convince.
In justice to Mr. Darwin, however, it must be admitted that the
conditions of fertility and sterility are very ill understood, and that
every day's advance in knowledge leads us to regard the hiatus in his
evidence as of less and less importance, when set against the multitude
of facts which harmonize with, or receive an explanation from, his
doctrines.
I adopt Mr. Darwin's hypothesis, therefore, subject to the production of
proof that physiological species may be produced by selective breeding;
just as a physical philosopher may accept the undulatory theory of
light, subject to the proof of the existence of the hypothetical ether;
or as the chemist adopts the atomic theory, subject to the proof of the
existence of atoms; and for exactly the same reasons, namely, that it
has an immense amount of primâ facie probability; that it is the only
means at present within reach of reducing the chaos of observed facts to
order; and lastly, that it is the most powerful instrument of
investigation which has been presented to naturalists since the
invention of the natural system of classification, and the commencement
of the systematic study of embryology.
But even leaving Mr. Darwin's views aside, the whole analogy of natural
operations furnishes so complete and crushing an argument against the
intervention of any but what are termed secondary causes, in the
production of all the phenomena of the universe; that, in view of the
intimate relations between Man and the rest of the living world; and
between the forces exerted by the latter and all other forces, I can see
no excuse for doubting that all are co-ordinated terms of Nature's great
progression, from the formless to the formed--from the inorganic to the
organic--from blind force to conscious intellect and will.
* * * * *
Science has fulfilled her function when she has ascertained and
enunciated truth; and were these pages addressed to men of science only,
I should now close this essay, knowing that my colleagues have learned
to respect nothing but evidence, and to believe that their highest duty
lies in submitting to it, however it may jar against their inclinations.
But desiring, as I do, to reach the wider circle of the intelligent
public, it would be unworthy cowardice were I to ignore the repugnance
with which the majority of my readers are likely to meet the conclusions
to which the most careful and conscientious study I have been able to
give to this matter, has led me.
On all sides I shall hear the cry--"We are men and women, not a mere
better sort of apes, a little longer in the leg, more compact in the
foot, and bigger in brain than your brutal Chimpanzees and Gorillas. The
power of knowledge--the conscience of good and evil--the pitiful
tenderness of human affections, raise us out of all real fellowship
with the brutes, however closely they may seem to approximate us."
To this I can only reply that the exclamation would be most just and
would have my own entire sympathy, if it were only relevant. But, it is
not I who seek to base Man's dignity upon his great toe, or insinuate
that we are lost if an Ape has a hippocampus minor. On the contrary, I
have done my best to sweep away this vanity. I have endeavoured to show
that no absolute structural line of demarcation, wider than that between
the animals which immediately succeed us in the scale, can be drawn
between the animal world and ourselves; and I may add the expression of
my belief that the attempt to draw a psychical distinction is equally
futile, and that even the highest faculties of feeling and of intellect
begin to germinate in lower forms of life.[32] At the same time, no one
is more strongly convinced than I am of the vastness of the gulf between
civilized man and the brutes; or is more certain that whether _from_
them or not, he is assuredly not _of_ them. No one is less disposed to
think lightly of the present dignity, or despairingly of the future
hopes, of the only consciously intelligent denizen of this world.
We are indeed told by those who assume authority in these matters, that
the two sets of opinions are incompatible, and that the belief in the
unity of origin of man and brutes involves the brutalization and
degradation of the former. But is this really so? Could not a sensible
child confute, by obvious arguments, the shallow rhetoricians who would
force this conclusion upon us? Is it, indeed, true, that the Poet, or
the Philosopher, or the Artist whose genius is the glory of his age, is
degraded from his high estate by the undoubted historical probability,
not to say certainty, that he is the direct descendant of some naked and
bestial savage, whose intelligence was just sufficient to make him a
little more cunning than the Fox, and by so much more dangerous than the
Tiger? Or is he bound to howl and grovel on all fours because of the
wholly unquestionable fact, that he was once an egg, which no ordinary
power of discrimination could distinguish from that of a Dog? Or is the
philanthropist or the saint to give up his endeavours to lead a noble
life, because the simplest study of man's nature reveals, at its
foundations, all the selfish passions and fierce appetites of the merest
quadruped? Is mother-love vile because a hen shows it, or fidelity base
because dogs possess it?
The common sense of the mass of mankind will answer these questions
without a moment's hesitation. Healthy humanity, finding itself hard
pressed to escape from real sin and degradation, will leave the brooding
over speculative pollution to the cynics and the "righteous overmuch"
who, disagreeing in everything else, unite in blind insensibility to the
nobleness of the visible world, and in inability to appreciate the
grandeur of the place Man occupies therein.
Nay more, thoughtful men, once escaped from the blinding influences of
traditional prejudice, will find in the lowly stock whence man has
sprung, the best evidence of the splendour of his capacities; and will
discern in his long progress through the Past, a reasonable ground of
faith in his attainment of a nobler Future.
They will remember that in comparing civilized man with the animal
world, one is as the Alpine traveller, who sees the mountains soaring
into the sky and can hardly discern where the deep shadowed crags and
roseate peaks end, and where the clouds of heaven begin. Surely the
awe-struck voyager may be excused if, at first, he refuses to believe
the geologist, who tells him that these glorious masses are, after all,
the hardened mud of primeval seas, or the cooled slag of subterranean
furnaces--of one substance with the dullest clay, but raised by inward
forces to that place of proud and seemingly inaccessible glory.
But the geologist is right; and due reflection on his teachings, instead
of diminishing our reverence and our wonder, adds all the force of
intellectual sublimity to the mere æsthetic intuition of the
uninstructed beholder.
And after passion and prejudice have died away, the same result will
attend the teachings of the naturalist respecting that great Alps and
Andes of the living world--Man. Our reverence for the nobility of
manhood will not be lessened by the knowledge, that Man is, in substance
and in structure, one with the brutes; for, he alone possesses the
marvellous endowment of intelligible and rational speech, whereby, in
the secular period of his existence, he has slowly accumulated and
organized the experience which is almost wholly lost with the cessation
of every individual life in other animals; so that now he stands raised
upon it as on a mountain top, far above the level of his humble fellows,
and transfigured from his grosser nature by reflecting, here and there,
a ray from the infinite source of truth.
_A succinct History of the Controversy respecting the
Cerebral Structure of Man and the Apes_
Up to the year 1857 all anatomists of authority, who had occupied
themselves with the cerebral structure of the Apes--Cuvier, Tiedemann,
Sandifort, Vrolik, Isidore G. St. Hilaire, Schroeder van der Kolk,
Gratiolet--were agreed that the brain of the Apes possesses a POSTERIOR
LOBE.
Tiedemann, in 1825, figured and acknowledged in the text of his
"Icones," the existence of the POSTERIOR CORNU of the lateral ventricle
in the Apes, not only under the title of "Scrobiculus parvus loco cornu
posterioris"--a fact which has been paraded--but as "cornu posterius"
(Icones, p. 54), a circumstance which has been, as sedulously, kept in
the back ground.
Cuvier (Lecons, T. iii. p. 103) says, "the anterior or lateral
ventricles possess a digital cavity [posterior cornu] only in Man and
the Apes.... Its presence depends on that of the posterior lobes."
Schroeder van der Kolk and Vrolik, and Gratiolet, had also figured and
described the posterior cornu in various Apes. As to the HIPPOCAMPUS
MINOR Tiedemann had erroneously asserted its absence in the Apes; but
Schroeder van der Kolk and Vrolik had pointed out the existence of what
they considered a rudimentary one in the Chimpanzee, and Gratiolet had
expressly affirmed its existence in these animals. Such was the state of
our information on these subjects in the year 1856.
In the year 1857, however, Professor Owen, either in ignorance of these
well-known facts or else unjustifiably suppressing them, submitted to
the Linnæan Society a paper "On the Characters, Principles of Division,
and Primary Groups of the Class Mammalia," which was printed in the
Society's Journal, and contains the following passage:--"In Man, the
brain presents an ascensive step in development, higher and more
strongly marked than that by which the preceding subclass was
distinguished from the one below it. Not only do the cerebral
hemispheres overlap the olfactory lobes and cerebellum, but they extend
in advance of the one and further back than the other. The posterior
development is so marked, that anatomists have assigned to that part the
character of a third lobe; _it is peculiar to the genus Homo, and
equally peculiar is the posterior horn of the lateral ventricle and the
'hippocampus minor,' which characterise the hind lobe of each
hemisphere_."--_Journal of the Proceedings of the Linnæan Society_, Vol.
ii. p. 19.
As the essay in which this passage stands had no less ambitious an aim
than the remodelling of the classification of the Mammalia, its author
might be supposed to have written under a sense of peculiar
responsibility, and to have tested, with especial care, the statements
he ventured to promulgate. And even if this be expecting too much,
hastiness, or want of opportunity for due deliberation, cannot now be
pleaded in extenuation of any shortcomings; for the propositions cited
were repeated two years afterwards in the Reade Lecture, delivered
before so grave a body as the University of Cambridge, in 1859.
When the assertions, which I have italicised in the above extract, first
came under my notice, I was not a little astonished at so flat a
contradiction of the doctrines current among well-informed anatomists;
but, not unnaturally imagining that the deliberate statements of a
responsible person must have some foundation in fact, I deemed it my
duty to investigate the subject anew before the time at which it would
be my business to lecture thereupon came round. The result of my
inquiries was to prove that Mr. Owen's three assertions, that "the third
lobe, the posterior horn of the lateral ventricle, and the hippocampus
minor," are "peculiar to the genus _Homo_," are contrary to the plainest
facts. I communicated this conclusion to the students of my class; and
then, having no desire to embark in a controversy which could not
redound to the honour of British science, whatever its issue, I turned
to more congenial occupations.
The time speedily arrived, however, when a persistence in this reticence
would have involved me in an unworthy paltering with truth.
At the meeting of the British Association at Oxford, in 1860, Professor
Owen repeated these assertions in my presence, and, of course, I
immediately gave them a direct and unqualified contradiction, pledging
myself to justify that unusual procedure elsewhere. I redeemed that
pledge by publishing, in the January number of the _Natural History
Review_ for 1861, an article wherein the truth of the three following
propositions was fully demonstrated (l. c. p. 71):--
"1. That the third lobe is neither peculiar to, nor
characteristic of, man seeing that it exists in all the
higher quadrumana."
"2. That the posterior cornu of the lateral ventricle is
neither peculiar to, nor characteristic of, man, inasmuch
as it also exists in the higher quadrumana."
"3. That the _hippocampus minor_ is neither peculiar to,
nor characteristic of, man, as it is found in certain of
the higher quadrumana."
Furthermore, this paper contains the following paragraph (p. 76):
"And lastly, Schroeder van der Kolk and Vrolik (op. cit.
p. 271), though they particularly note that 'the lateral
ventricle is distinguished from that of Man by the very
defective proportions of the posterior cornu, wherein only
a stripe is visible as an indication of the hippocampus
minor;' yet the Figure 4, in their second Plate, shows
that this posterior cornu is a perfectly distinct and
unmistakeable structure, quite as large as it often is in
Man. It is the more remarkable that Professor Owen should
have overlooked the explicit statement and figure of these
authors, as it is quite obvious, on comparison of the
figures, that his woodcut of the brain of a Chimpanzee (l.
c. p. 19) is a reduced copy of the second figure of
Messrs. Schroeder van der Kolk and Vrolik's first Plate.
"As M. Gratiolet (l. c. p. 18), however, is careful to
remark, 'unfortunately the brain which they have taken as
a model was greatly altered (profondément affaissé),
whence the general form of the brain is given in these
plates in a manner which is altogether incorrect.' Indeed,
it is perfectly obvious, from a comparison of a section of
the skull of the Chimpanzee with these figures, that such
is the case; and it is greatly to be regretted that so
inadequate a figure should have been taken as a typical
representation of the Chimpanzee's brain."
From this time forth, the untenability of his position might have been
as apparent to Professor Owen as it was to every one else; but, so far
from retracting the grave errors into which he had fallen, Professor
Owen has persisted in and reiterated them; first, in a lecture delivered
before the Royal Institution on the 19th of March, 1861, which is
admitted to have been accurately reproduced in the "Athenæum" for the
23rd of the same month, in a letter addressed by Professor Owen to that
journal on the 30th of March. The "Athenæum" report was accompanied by a
diagram purporting to represent a Gorilla's brain, but in reality so
extraordinary a misrepresentation, that Professor Owen substantially,
though not explicitly, withdraws it in the letter in question. In
amending this error, however, Professor Owen fell into another of much
graver import, as his communication concludes with the following
paragraph: "For the true proportion in which the cerebrum covers the
cerebellum in the highest Apes, reference should be made to the figure
of the undissected brain of the Chimpanzee in my 'Reade's Lecture on the
Classification, &c. of the Mammalia,' p. 25, fig. 7, 8vo. 1859."
It would not be credible, if it were not unfortunately true, that this
figure, to which the trusting public is referred, without a word of
qualification, "for the true proportion in which the cerebrum covers the
cerebellum in the highest Apes," is exactly that unacknowledged copy of
Schroeder van der Kolk and Vrolik's figure whose utter inaccuracy had
been pointed out years before by Gratiolet, and had been brought to
Professor Owen's knowledge by myself in the passage of my article in the
"Natural History Review" above quoted.
I drew public attention to this circumstance again in my reply to
Professor Owen, published in the "Athenæum" for April 13th, 1861; but
the exploded figure was reproduced once more by Professor Owen, without
the slightest allusion to its inaccuracy, in the "Annals of Natural
History" for June 1861!
This proved too much for the patience of the original authors of the
figure, Messrs. Schroeder van der Kolk and Vrolik, who, in a note
addressed to the Academy of Amsterdam, of which they were members,
declared themselves to be, though decided opponents of all forms of the
doctrine of progressive development, above all things, lovers of truth:
and that, therefore, at whatever risk of seeming to lend support to
views which they disliked, they felt it their duty to take the first
opportunity of publicly repudiating Professor Owen's misuse of their
authority.
In this note they frankly admitted the justice of the criticisms of M.
Gratiolet, quoted above, and they illustrated, by new and careful
figures, the posterior lobe, the posterior cornu, and the hippocampus
minor of the Orang. Furthermore, having demonstrated the parts, at one
of the sittings of the Academy, they add, "la présence des parties
contestées y a été universellement reconnue par les anatomistes présents
à la séance. Le seul doute qui soit resté se rapporte au pes Hippocampi
minor.... A l'état frais l'indice du petit pied d'Hippocampe était plus
prononcé que maintenant."
Professor Owen repeated his erroneous assertions at the meeting of the
British Association in 1861, and again, without any obvious necessity,
and without adducing a single new fact or new argument, or being able in
any way to meet the crushing evidence from original dissections of
numerous Apes' brains, which had in the meanwhile been brought forward
by Prof. Rolleston,[33] F.R.S., Mr. Marshall,[34] F.R.S., Mr.
Flower,[35] Mr. Turner,[36] and myself,[37] revived the subject at the
Cambridge meeting of the same body in 1862. Not content with the
tolerably vigorous repudiation which these unprecedented proceedings met
with in Section D, Professor Owen sanctioned the publication of a
version of his own statements, accompanied by a strange
misrepresentation of mine (as may be seen by comparison of the "Times"
report of the discussion), in the "Medical Times" for October 11th,
1862. I subjoin the conclusion of my reply in the same journal for
October 25th.
"If this were a question of opinion, or a question of
interpretation of parts or of terms,--were it even a
question of observation in which the testimony of my own
senses alone was pitted against that of another person, I
should adopt a very different tone in discussing this
matter. I should, in all humility, admit the likelihood of
having myself erred in judgment, failed in knowledge, or
been blinded by prejudice.
"But no one pretends now, that the controversy is one of
terms or of opinions. Novel and devoid of authority as
some of Professor Owen's proposed definitions may have
been, they might be accepted without changing the great
features of the case. Hence, though special investigations
into these matters have been undertaken during the last
two years by Dr. Allen Thomson, by Dr. Rolleston, by Mr.
Marshall, and by Mr. Flower, all, as you are aware,
anatomists of repute in this country, and by Professors
Schroeder Van der Kolk, and Vrolik (whom Professor Owen
incautiously tried to press into his own service) on the
Continent, all these able and conscientious observers have
with one accord testified to the accuracy of my
statements, and to the utter baselessness of the
assertions of Professor Owen. Even the venerable Rudolph
Wagner, whom no man will accuse of progressionist
proclivities, has raised his voice on the same side; while
not a single anatomist, great or small, has supported
Professor Owen.
"Now, I do not mean to suggest that scientific differences
should be settled by universal suffrage, but I do conceive
that solid proofs must be met by something more than empty
and unsupported assertions. Yet during the two years
through which this preposterous controversy has dragged
its weary length, Professor Owen has not ventured to
bring forward a single preparation in support of his
often-repeated assertions.
"The case stands thus, therefore:--Not only are the
statements made by me in consonance with the doctrines of
the best older authorities, and with those of all recent
investigators, but I am quite ready to demonstrate them on
the first monkey that comes to hand; while Professor
Owen's assertions are not only in diametrical opposition
to both old and new authorities, but he has not produced,
and, I will add, cannot produce, a single preparation
which justifies them."
I now leave this subject, for the present.--For the credit of my calling
I should be glad to be, hereafter, for ever silent upon it. But,
unfortunately, this is a matter upon which, after all that has occurred,
no mistake or confusion of terms is possible--and in affirming that the
posterior lobe, the posterior cornu, and the hippocampus minor exist in
certain Apes, I am stating either that which is true, or that which I
must know to be false. The question has thus become one of personal
veracity. For myself, I will accept no other issue than this, grave as
it is, to the present controversy.
FOOTNOTES:
[25] It will be understood that, in the preceding Essay, I have selected
for notice from the vast mass of papers which have been written upon the
man-like Apes, only those which seem to me to be of special moment.
[26] We are not at present thoroughly acquainted with the brain of the
Gorilla, and therefore, in discussing cerebral characters, I shall take
that of the Chimpanzee as my highest term among the Apes.
[27] "More than once," says Peter Camper, "have I met with more than six
lumbar vertebræ in man.... Once I found thirteen ribs and four lumbar
vertebræ." Fallopius noted thirteen pair of ribs and only four lumbar
vertebræ; and Eustachius once found eleven dorsal vertebræ and six
lumbar vertebræ.--"OEuvres de Pierre Camper," T. 1, p. 42. As Tyson
states, his "Pygmie" had thirteen pair of ribs and five lumbar vertebræ.
The question of the curves of the spinal column in the Apes requires
further investigation.
[28] It has been affirmed that Hindoo crania sometimes contain as little
as 27 ounces of water, which would give a capacity of about 46 cubic
inches. The minimum capacity which I have assumed above, however, is
based upon the valuable tables published by Professor R. Wagner in his
"Vorstudien zu einer wissenschaftlichen Morphologie und Physiologie des
menschlichen Gehirns." As the result of the careful weighing of more
than 900 human brains, Professor Wagner states that one-half weighed
between 1200 and 1400 grammes, and that about two-ninths, consisting for
the most part of male brains, exceed 1400 grammes. The lightest brain of
an adult male, with sound mental faculties, recorded by Wagner, weighed
1020 grammes. As a gramme equals 15.4 grains, and a cubic inch of water
contains 252.4 grains, this is equivalent to 62 cubic inches of water;
so that as brain is heavier than water, we are perfectly safe against
erring on the side of diminution in taking this as the smallest capacity
of any adult male human brain. The only adult male brain, weighing as
little as 970 grammes, is that of an idiot; but the brain of an adult
woman, against the soundness of whose faculties nothing appears, weighed
as little as 907 grammes (55.3 cubic inches of water); and Reid gives an
adult female brain of still smaller capacity. The heaviest brain (1872
grammes, or about 115 cubic inches) was, however, that of a woman; next
to it comes the brain of Cuvier (1861 grammes), then Byron (1807
grammes), and then an insane person (1783 grammes). The lightest adult
brain recorded (720 grammes) was that of an idiotic female. The brains
of five children, four years old, weighed between 1275 and 992 grammes.
So that it may be safely said, that an average European child of four
years old has a brain twice as large as that of an adult Gorilla.
[29] In speaking of the foot of his "Pygmie," Tyson remarks, p.
13:--"But this part in the formation and in its function too, being
liker a Hand than a Foot: for the distinguishing this sort of animals
from others, I have thought whether it might not be reckoned and called
rather Quadrumanus than Quadrupes, _i.e._ a four-handed rather than a
four-footed animal."
As this passage was published in 1699, M. I. G. St. Hilaire is clearly
in error in ascribing the invention of the term "quadrumanous" to
Buffon, though "bimanous" may belong to him. Tyson uses "Quadrumanus" in
several places, as at p. 91.... "Our _Pygmie_ is no Man, nor yet the
_common Ape_, but a sort of _Animal_ between both; and though a _Biped_,
yet of the _Quadrumanus_-kind: though some _Men_ too have been observed
to use their _Feet_ like _Hands_, as I have seen several."
[30] See the note at the end of this essay for a succinct history of the
controversy to which allusion is here made.
[31] I say _help_ to furnish: for I by no means believe that it was any
original difference of cerebral quality, or quantity, which caused that
divergence between the human and the pithecoid stirpes, which has ended
in the present enormous gulf between them. It is no doubt perfectly
true, in a certain sense, that all difference of function is a result of
difference of structure; or, in other words, of difference in the
combination of the primary molecular forces of living substance; and,
starting from this undeniable axiom, objectors occasionally, and with
much seeming plausibility, argue that the vast intellectual chasm
between the Ape and Man implies a corresponding structural chasm in the
organs of the intellectual functions; so that, it is said, the
non-discovery of such vast differences proves, not that they are absent,
but that Science is incompetent to detect them. A very little
consideration, however, will, I think, show the fallacy of this
reasoning. Its validity hangs upon the assumption, that intellectual
power depends altogether on the brain--whereas the brain is only one
condition out of many on which intellectual manifestations depend; the
others being, chiefly, the organs of the senses and the motor
apparatuses, especially those which are concerned in prehension and in
the production of articulate speech.
A man born dumb, notwithstanding his great cerebral mass and his
inheritance of strong intellectual instincts, would be capable of few
higher intellectual manifestations than an Orang or a Chimpanzee, if he
were confined to the society of dumb associates. And yet there might not
be the slightest discernible difference between his brain and that of a
highly intelligent and cultivated person. The dumbness might be the
result of a defective structure of the mouth, or of the tongue, or a
mere defective innervation of these parts; or it might result from
congenital deafness, caused by some minute defect of the internal ear,
which only a careful anatomist could discover.
The argument, that because there is an immense difference between a
Man's intelligence and an Ape's, therefore, there must be an equally
immense difference between their brains, appears to me to be about as
well based as the reasoning by which one should endeavour to prove that,
because there is a "great gulf" between a watch that keeps accurate time
and another that will not go at all, there is therefore a great
structural hiatus between the two watches. A hair in the balance-wheel,
a little rust on a pinion, a bend in a tooth of the escapement, a
something so slight that only the practised eye of the watchmaker can
discover it, may be the source of all the difference.
And believing, as I do, with Cuvier, that the possession of articulate
speech is the grand distinctive character of man (whether it be
absolutely peculiar to him or not), I find it very easy to comprehend,
that some equally inconspicuous structural difference may have been the
primary cause of the immeasurable and practically infinite divergence of
the Human from the Simian Stirps.
[32] It is so rare a pleasure for me to find Professor Owen's opinions
in entire accordance with my own, that I cannot forbear from quoting a
paragraph which appeared in his Essay "On the Characters, &c., of the
Class Mammalia," in the "Journal of the Proceedings of the Linnean
Society of London" for 1857, but is unaccountably omitted in the "Reade
Lecture" delivered before the University of Cambridge two years later,
which is otherwise nearly a reprint of the paper in question. Prof. Owen
writes:
"Not being able to appreciate or conceive of the
distinction between the psychical phenomena of a
Chimpanzee and of a Boschisman or of an Aztec, with
arrested brain growth, as being of a nature so essential
as to preclude a comparison between them, or as being
other than a difference of degree, I cannot shut my eyes
to the significance of that all-pervading similitude of
structure--every tooth, every bone, strictly
homologous--which makes the determination of the
difference between _Homo_ and _Pithecus_ the anatomist's
difficulty."
Surely it is a little singular that the "anatomist," who finds it
"difficult" to "determine the difference" between _Homo_ and _Pithecus_,
should yet range them on anatomical grounds, in distinct sub-classes!
[33] On the Affinities of the Brain of the Orang. Nat. Hist. Review,
April, 1861.
[34] On the Brain of a young Chimpanzee. Ibid., July, 1861.
[35] On the Posterior lobes of the Cerebrum of the Quadrumana.
Philosophical Transactions, 1862.
[36] On the anatomical Relations of the Surfaces of the Tentorium to the
Cerebrum and Cerebellum in Man and the lower Mammals. Proceedings of the
Royal Society of Edinburgh, March, 1862.
[37] On the Brain of Ateles. Proceedings of Zoological Society, 1861.
III
ON SOME FOSSIL REMAINS OF MAN.
I have endeavoured to show, in the preceding Essay, that the ANTHROPINI,
or Man Family, form a very well defined group of the Primates, between
which and the immediately following Family, the CATARHINI, there is, in
the existing world, the same entire absence of any transitional form or
connecting link, as between the CATARHINI and PLATYRHINI.
It is a commonly received doctrine, however, that the structural
intervals between the various existing modifications of organic beings
may be diminished, or even obliterated, if we take into account the long
and varied succession of animals and plants which have preceded these
now living and which are known to us only by their fossilized remains.
How far this doctrine is well based, how far, on the other hand, as our
knowledge at present stands, it is an overstatement of the real facts of
the case, and an exaggeration of the conclusions fairly deducible from
them, are points of grave importance, but into the discussion of which I
do not, at present, propose to enter. It is enough that such a view of
the relations of extinct to living beings has been propounded, to lead
us to inquire, with anxiety, how far the recent discoveries of human
remains in a fossil state bear out, or oppose, that view.
I shall confine myself, in discussing this question, to those
fragmentary Human skulls from the caves of Engis in the valley of the
Meuse, in Belgium, and of the Neanderthal near Düsseldorf, the
geological relations of which have been examined with so much care by
Sir Charles Lyell; upon whose high authority I shall take it for
granted, that the Engis skull belonged to a contemporary of the Mammoth
(_Elephas primigenius_) and of the woolly Rhinoceros (_Rhinocerus
tichorhinus_), with the bones of which it was found associated; and that
the Neanderthal skull is of great, though uncertain, antiquity. Whatever
be the geological age of the latter skull, I conceive it is quite safe
(on the ordinary principles of paleontological reasoning) to assume that
the former takes us to, at least, the further side of the vague
biological limit, which separates the present geological epoch from that
which immediately preceded it. And there can be no doubt that the
physical geography of Europe has changed wonderfully, since the bones of
Men and Mammoths, Hyænas and Rhinoceroses were washed pell-mell into the
cave of Engis.
The skull from the cave of Engis was originally discovered by Professor
Schmerling, and was described by him, together with other human remains
disinterred at the same time, in his valuable work, "Recherches sur les
ossemens fossiles découverts dans les cavernes de la Province de Liège,"
published in 1833 (p. 59, _et seq._), from which the following
paragraphs are extracted, the precise expressions of the author being,
as far as possible, preserved.
"In the first place, I must remark that these human
remains, which are in my possession, are characterized,
like the thousands of bones which I have lately been
disinterring, by the extent of the decomposition which
they have undergone, which is precisely the same as that
of the extinct species: all, with a few exceptions, are
broken; some few are rounded, as is frequently found to be
the case in fossil remains of other species. The fractures
are vertical or oblique; none of them are eroded; their
colour does not differ from that of other fossil bones,
and varies from whitish yellow to blackish. All are
lighter than recent bones, with the exception of those
which have a calcareous incrustation, and the cavities of
which are filled with such matter.
"The cranium which I have caused to be figured, Plate I.,
figs. 1, 2, is that of an old person. The sutures are
beginning to be effaced: all the facial bones are wanting,
and of the temporal bones only a fragment of that of the
right side is preserved.
[Illustration: FIG. 22.--The skull from the cave of Engis--viewed from
the right side. _a_, glabella, _b_, occipital protuberance, (_a_ to _b_
glabello-occipital line), _c_, auditory foramen.]
"The face and the base of the cranium had been detached
before the skull was deposited in the cave, for we were
unable to find those parts, though the whole cavern was
regularly searched. The cranium was met with at a depth of
a metre and a half [five feet nearly] hidden under an
osseous breccia, composed of the remains of small animals,
and containing one rhinoceros tusk, with several teeth of
horses and of ruminants. This breccia, which has been
spoken of above (p. 30), was a metre [3-1/4 feet about]
wide, and rose to the height of a metre and a half above
the floor of the cavern, to the walls of which it adhered
strongly.
"The earth which contained this human skull exhibited no
trace of disturbance: teeth of rhinoceros, horse, hyæna,
and bear, surrounded it on all sides.
"The famous Blumenbach[38] has directed attention to the
differences presented by the form and the dimensions of
human crania of different races. This important work would
have assisted us greatly, if the face, a part essential
for the determination of race, with more or less accuracy,
had not been wanting in our fossil cranium.
"We are convinced that even if the skull had been
complete, it would not have been possible to pronounce,
with certainty, upon a single specimen; for individual
variations are so numerous in the crania of one and the
same race, that one cannot, without laying oneself open to
large chances of error, draw any inference from a single
fragment of a cranium to the general form of the head to
which it belonged.
"Nevertheless, in order to neglect no point respecting the
form of this fossil skull, we may observe that, from the
first, the elongated and narrow form of the forehead
attracted our attention.
"In fact, the slight elevation of the frontal, its
narrowness, and the form of the orbit, approximate it more
nearly to the cranium of an Ethiopian than to that of an
European: the elongated form and the produced occiput are
also characters which we believe to be observable in our
fossil cranium; but to remove all doubt upon that subject
I have caused the contours of the cranium of an European
and of an Ethiopian to be drawn and the foreheads
represented. Plate II., Figs. 1 and 2, and, in the same
plate, Figs. 3 and 4, will render the differences easily
distinguishable; and a single glance at the figures, will
be more instructive than a long and wearisome description.
"At whatever conclusion we may arrive as to the origin of
the man from whence this fossil skull proceeded, we may
express an opinion without exposing ourselves to a
fruitless controversy. Each may adopt the hypothesis which
seems to him most probable: for my own part, I hold it to
be demonstrated that this cranium has belonged to a person
of limited intellectual faculties, and we conclude thence
that it belonged to a man of a low degree of civilization:
a deduction which is borne out by contrasting the capacity
of the frontal with that of the occipital region.
"Another cranium of a young individual was discovered in
the floor of the cavern beside the tooth of an elephant;
the skull was entire when found, but the moment it was
lifted it fell into pieces, which I have not, as yet, been
able to put together again. But I have represented the
bones of the upper jaw, Plate I., Fig. 5. The state of the
alveoli and the teeth, shows that the molars had not yet
pierced the gum. Detached milk molars and some fragments
of a human skull, proceed from this same place. The Figure
3, represents a human superior incisor tooth, the size of
which is truly remarkable.[39]
"Figure 4 is a fragment of a superior maxillary bone, the
molar teeth of which are worn down to the roots.
"I possess two vertebræ, a first and last dorsal.
"A clavicle of the left side (see Plate III., Fig. 1);
although it belonged to a young individual, this bone
shows that he must have been of great stature.[40]
"Two fragments of the radius, badly preserved, do not
indicate that the height of the man, to whom they
belonged, exceeded five feet and a half.
"As to the remains of the upper extremities, those which
are in my possession, consist merely of a fragment of an
ulna and of a radius (Plate III., Fig. 5 and 6).
"Figure 2, Plate IV., represents a metacarpal bone,
contained in the breccia, of which we have spoken; it was
found in the lower part above the cranium: add to this
some metacarpal bones, found at very different distances,
half-a-dozen metatarsals, three phalanges of the hand, and
one of the foot.
"This is a brief enumeration of the remains of human bones
collected in the cavern of Engis, which has preserved for
us the remains of three individuals, surrounded by those
of the Elephant, of the Rhinoceros, and of Carnivora of
species unknown in the present creation."
* * * * *
From the cave of Engihoul, opposite that of Engis, on the right bank of
the Meuse, Schmerling obtained the remains of three other individuals of
Man, among which were only two fragments of parietal bones, but many
bones of the extremities. In one case, a broken fragment of an ulna was
soldered to a like fragment of a radius by stalagmite, a condition
frequently observed among the bones of the Cave Bear (_Ursus spelæus_),
found in the Belgian caverns.
It was in the cavern of Engis that Professor Schmerling found, incrusted
with stalagmite and joined to a stone, the pointed bone implement, which
he has figured in Fig. 7 of his Plate XXXVI., and worked flints were
found by him in all those Belgian caves, which contained an abundance of
fossil bones.
A short letter from M. Geoffroy St. Hilaire, published in the Comptes
Rendus of the Academy of Sciences of Paris, for July 2nd, 1838, speaks
of a visit (and apparently a very hasty one) paid to the collection of
Professor "Schermidt" (which is presumably a misprint for Schmerling) at
Liège. The writer briefly criticises the drawings which illustrate
Schmerling's work, and affirms that the "human cranium is a little
longer than it is represented" in Schmerling's figure. The only other
remark worth quoting is this:--"The aspect of the human bones differs
little from that of the cave bones, with which we are familiar, and of
which there is a considerable collection in the same place. With respect
to their special forms, compared with those of the varieties of recent
human crania, few _certain_ conclusions can be put forward; for much
greater differences exist between the different specimens of
well-characterized varieties, than between the fossil cranium of Liège
and that of one of those varieties selected as a term of comparison."
Geoffroy St. Hilaire's remarks are, it will be observed, little but an
echo of the philosophic doubts of the describer and discoverer of the
remains. As to the critique upon Schmerling's figures, I find that the
side view given by the latter is really about 3/10ths of an inch shorter
than the original, and that the front view is diminished to about the
same extent. Otherwise the representation is not, in any way,
inaccurate, but corresponds very well with the cast which is in my
possession.
A piece of the occipital bone, which Schmerling seems to have missed,
has since been fitted on to the rest of the cranium by an accomplished
anatomist, Dr. Spring of Liège, under whose direction an excellent
plaster cast was made for Sir Charles Lyell. It is upon and from a
duplicate of that cast that my own observations and the accompanying
figures, the outlines of which are copied from very accurate Camera
lucida drawings, by my friend Mr. Busk, reduced to one-half of the
natural size, are made.
As Professor Schmerling observes, the base of the skull is destroyed,
and the facial bones are entirely absent; but the roof of the cranium,
consisting of the frontal, parietal, and the greater part of the
occipital bones, as far as the middle of the occipital foramen, is
entire or nearly so. The left temporal bone is wanting. Of the right
temporal, the parts in the immediate neighbourhood of the auditory
foramen, the mastoid process, and a considerable portion of the squamous
element of the temporal are well preserved (Fig. 22).
The lines of fracture which remain between the coadjusted pieces of the
skull, and are faithfully displayed in Schmerling's figure, are readily
traceable in the cast. The sutures are also discernible, but the complex
disposition of their serrations, shown in the figure, is not obvious in
the cast. Though the ridges which give attachment to muscles are not
excessively prominent, they are well marked, and taken together with the
apparently well developed frontal sinuses, and the condition of the
sutures, leave no doubt on my mind that the skull is that of an adult,
if not middle-aged man.
The extreme length of the skull is 7.7 inches. Its extreme breadth,
which corresponds very nearly with the interval between the parietal
protuberances, is not more than 5.4 inches. The proportion of the length
to the breadth is therefore very nearly as 100 to 70. If a line be drawn
from the point at which the brow curves in towards the root of the nose,
and which is called the "glabella" (_a_), (Fig. 22), to the occipital
protuberance (_b_), and the distance to the highest point of the arch of
the skull be measured perpendicularly from this line, it will be found
to be 4.75 inches. Viewed from above, Fig. 23, A, the forehead presents
an evenly rounded curve, and passes into the contour of the sides and
back of the skull, which describes a tolerably regular elliptical curve.
The front view (Fig. 23, B) shows that the roof of the skull was very
regularly and elegantly arched in the transverse direction, and that the
transverse diameter was a little less below the parietal protuberances,
than above them. The forehead cannot be called narrow in relation to the
rest of the skull, nor can it be called a retreating forehead; on the
contrary, the antero-posterior contour of the skull is well arched, so
that the distance along that contour, from the nasal depression to the
occipital protuberance, measures about 13.75 inches. The transverse arc
of the skull, measured from one auditory foramen to the other, across
the middle of the sagittal suture, is about 13 inches. The sagittal
suture itself is 5.5 inches long.
The supraciliary prominences or brow-ridges (on each side of _a_, Fig.
22) are well, but not excessively, developed, and are separated by a
median depression. Their principal elevation is disposed so obliquely
that I judge them to be due to large frontal sinuses.
If a line joining the glabella and the occipital protuberance (_a_, _b_,
Fig. 22) be made horizontal, no part of the occipital region projects
more than 1/10th an inch behind the posterior extremity of that line,
and the upper edge of the auditory foramen (_c_) is almost in contact
with a line drawn parallel with this upon the outer surface of the
skull.
A transverse line drawn from one auditory foramen to the other
traverses, as usual, the forepart of the occipital foramen. The
capacity of the interior of this fragmentary skull has not been
ascertained.
[Illustration: FIG. 23.--The Engis skull viewed from above (_A_) and in
front (_B_).]
* * * * *
The history of the Human remains from the cavern in the Neanderthal may
best be given in the words of their original describer, Dr.
Schaaffhausen,[41] as translated by Mr. Busk.
"In the early part of the year 1857, a human skeleton was
discovered in a limestone cave in the Neanderthal, near
Hochdal, between Düsseldorf and Elberfeld. Of this,
however, I was unable to procure more than a plaster cast
of the cranium, taken at Elberfeld, from which I drew up
an account of its remarkable conformation, which was, in
the first instance, read on the 4th of February, 1857, at
the meeting of the Lower Rhine Medical and Natural History
Society, at Bonn.[42] Subsequently Dr. Fuhlrott, to whom
science is indebted for the preservation of these bones,
which were not at first regarded as human, and into whose
possession they afterwards came, brought the cranium from
Elberfeld to Bonn, and entrusted it to me for more
accurate anatomical examination. At the General Meeting of
the Natural History Society of Prussian Rhineland and
Westphalia, at Bonn, on the 2nd of June, 1857,[43] Dr.
Fuhlrott himself gave a full account of the locality, and
of the circumstances under which the discovery was made.
He was of opinion that the bones might be regarded as
fossil; and in coming to this conclusion, he laid especial
stress upon the existence of dendritic deposits, with
which their surface was covered, and which were first
noticed upon them by Professor Mayer. To this
communication I appended a brief report on the results of
my anatomical examination of the bones. The conclusions at
which I arrived were:--1st. That the extraordinary form
of the skull was due to a natural conformation hitherto
not known to exist, even in the most barbarous races. 2nd.
That these remarkable human remains belonged to a period
antecedent to the time of the Celts and Germans, and were
in all probability derived from one of the wild races of
Northwestern Europe, spoken of by Latin writers; and which
were encountered as autochthones by the German immigrants.
And 3rdly. That it was beyond doubt that these human
relics were traceable to a period at which the latest
animals of the diluvium still existed; but that no proof
of this assumption, nor consequently of their so-termed
_fossil_ condition, was afforded by the circumstances
under which the bones were discovered."
As Dr. Fuhlrott has not yet published his description of these
circumstances, I borrow the following account of them from one of his
letters. "A small cave or grotto, high enough to admit a man, and about
15 feet deep from the entrance, which is 7 or 8 feet wide, exists in the
southern wall of the gorge of the Neanderthal, as it is termed, at a
distance of about 100 feet from the Düssel, and about 60 feet above the
bottom of the valley. In its earlier and uninjured condition, this
cavern opened upon a narrow plateau lying in front of it, and from which
the rocky wall descended almost perpendicularly into the river. It could
be reached, though with difficulty, from above. The uneven floor was
covered to a thickness of 4 or 5 feet with a deposit of mud, sparingly
intermixed with rounded fragments of chert. In the removing of this
deposit, the bones were discovered. The skull was first noticed, placed
nearest to the entrance of the cavern; and further in, the other bones,
lying in the same horizontal plane. Of this I was assured, in the most
positive terms, by two labourers who were employed to clear out the
grotto, and who were questioned by me on the spot. At first no idea was
entertained of the bones being human; and it was not till several weeks
after their discovery that they were recognised as such by me, and
placed in security. But, as the importance of the discovery was not at
the time perceived, the labourers were very careless in the collecting,
and secured chiefly only the larger bones; and to this circumstance it
may be attributed that fragments merely of the probably perfect skeleton
came into my possession."
My anatomical examination of these bones afforded the following
results:--
The cranium is of unusual size, and of a long elliptical form. A most
remarkable peculiarity is at once obvious in the extraordinary
development of the frontal sinuses, owing to which the superciliary
ridges, which coalesce completely in the middle, are rendered so
prominent, that the frontal bone exhibits a considerable hollow or
depression above, or rather behind them, whilst a deep depression is
also formed in the situation of the root of the nose. The forehead is
narrow and low, though the middle and hinder portions of the cranial
arch are well developed. Unfortunately, the fragment of the skull that
has been preserved consists only of the portion situated above the roof
of the orbits and the superior occipital ridges, which are greatly
developed, and almost conjoined so as to form a horizontal eminence. It
includes almost the whole of the frontal bone, both parietals, a small
part of the squamous and the upper-third of the occipital. The recently
fractured surfaces show that the skull was broken at the time of its
disinterment. The cavity holds 16,876 grains of water, whence its
cubical contents may be estimated at 57.64 inches, or 1033.24 cubic
centimetres. In making this estimation, the water is supposed to stand
on a level with the orbital plate of the frontal, with the deepest notch
in the squamous margin of the parietal, and with the superior
semicircular ridges of the occipital. Estimated in dried millet-seed,
the contents equalled 31 ounces, Prussian Apothecaries' weight. The
semicircular line indicating the upper boundary of the attachment of the
temporal muscle, though not very strongly marked, ascends nevertheless
to more than half the height of the parietal bone. On the right
superciliary ridge is observable an oblique furrow or depression,
indicative of an injury received during life.[44] The coronal and
sagittal sutures are on the exterior nearly closed, and on the inside
so completely ossified as to have left no traces whatever, whilst the
lambdoidal remains quite open. The depressions for the Pacchionian
glands are deep and numerous; and there is an unusually deep vascular
groove immediately behind the coronal suture, which, as it terminates in
a foramen, no doubt transmitted a _vena emissaria_. The course of the
frontal suture is indicated externally by a slight ridge; and where it
joins the coronal, this ridge rises into a small protuberance. The
course of the sagittal suture is grooved, and above the angle of the
occipital bone the parietals are depressed.
mm.[45]
The length of the skull from the nasal
process of the frontal over the vertex
to the superior semicircular lines of the
occipital measures 303 (300)=12.0".
Circumference over the orbital ridges and
the superior semicircular lines of the
occipital 590 (590)=23.37" or 23".
Width of the frontal from the middle of
the temporal line on one side to the
same point on the opposite 104 (114)=4.1"-4.5".
Length of the frontal from the nasal
process to the coronal suture 133 (125)=5.25"-5".
Extreme width of the frontal sinuses 25 (23)=1.0"-0.9".
Vertical height above a line joining the
deepest notches in the squamous border
of the parietals 70 = 2.75".
Width of hinder part of skull from one
parietal protuberance to the other 138 (150)=5.4"-5.9".
Distance from the upper angle of the
occipital to the superior semicircular
lines 51 (60)=1.9"-2.4".
Thickness of the bone at the parietal
protuberance 8.
---- at the angle of the occipital 9.
---- at the superior semicircular line of
the occipital 10 = 0.3".
Besides the cranium, the following bones have been secured:--
1. Both thigh-bones, perfect. These, like the skull, and all the other
bones, are characterized by their unusual thickness, and the great
development of all the elevations and depressions for the attachment of
muscles. In the Anatomical Museum at Bonn, under the designation of
"Giant's-bones," are some recent thigh-bones, with which in thickness
the foregoing pretty nearly correspond, although they are shorter.
Giant's bones. Fossil bones.
mm. mm.
Length 542 = 21.4" 438 = 17.4"
Diameter of head of femur 54 = 2.14" 53 = 2.0"
" of lower articular end, from
one condyle to the other 89 = 3.5" 87 = 3.4"
Diameter of femur in the middle 33 = 1.2" 30 = 1.1"
2. A perfect right humerus, whose size shows that it belongs to the
thigh-bones.
mm.
Length 312 = 12.3"
Thickness in the middle 26 = 1.0"
Diameter of head 49 = 1.9"
Also a perfect right radius of corresponding dimensions, and the
upper-third of a right ulna corresponding to the humerus and radius.
3. A left humerus, of which the upper-third is wanting, and which is so
much slenderer than the right as apparently to belong to a distinct
individual; a left _ulna_, which, though complete, is pathologically
deformed, the coronoid process being so much enlarged by bony growth,
that flexure of the elbow beyond a right angle must have been
impossible; the anterior fossa of the humerus for the reception of the
coronoid process being also filled up with a similar bony growth. At the
same time, the olecranon is curved strongly downwards. As the bone
presents no sign of rachitic degeneration, it may be supposed that an
injury sustained during life was the cause of the anchylosis. When the
left ulna is compared with the right radius, it might at first sight be
concluded that the bones respectively belonged to different individuals,
the ulna being more than half an inch too short for articulation with a
corresponding radius. But it is clear that this shortening, as well as
the attenuation of the left humerus, are both consequent upon the
pathological condition above described.
4. A left _ilium_, almost perfect, and belonging to the femur; a
fragment of the right _scapula_; the anterior extremity of a rib of the
right side; and the same part of a rib of the left side; the hinder part
of a rib of the right side; and, lastly, two hinder portions and one
middle portion of ribs, which, from their unusually rounded shape, and
abrupt curvature, more resemble the ribs of a carnivorous animal than
those of a man. Dr. H. v. Meyer, however, to whose judgment I defer,
will not venture to declare them to be ribs of any animal; and it only
remains to suppose that this abnormal condition has arisen from an
unusually powerful development of the thoracic muscles.
The bones adhere strongly to the tongue, although, as proved by the use
of hydrochloric acid, the greater part of the cartilage is still
retained in them, which appears, however, to have undergone that
transformation into gelatine which has been observed by v. Bibra in
fossil bones. The surface of all the bones is in many spots covered with
minute black specks, which, more especially under a lens, are seen to be
formed of very delicate _dendrites_. These deposits, which were first
observed on the bones by Dr. Meyer, are most distinct on the inner
surface of the cranial bones. They consist of a ferruginous compound,
and, from their black colour, may be supposed to contain manganese.
Similar dendritic formations also occur, not unfrequently, on laminated
rocks, and are usually found in minute fissures and cracks. At the
meeting of the Lower Rhine Society at Bonn, on the 1st April, 1857,
Prof. Meyer stated that he had noticed in the museum of Poppelsdorf
similar dendritic crystallizations on several fossil bones of animals,
and particularly on those of _Ursus spelæus_, but still more abundantly
and beautifully displayed on the fossil bones and teeth of _Equus
adamiticus_, _Elephas primigenius_, &c., from the caves of Bolve and
Sundwig. Faint indications of similar _dendrites_ were visible in a
Roman skull from Siegburg; whilst other ancient skulls, which had lain
for centuries in the earth, presented no trace of them.[46] I am
indebted to H. v. Meyer for the following remarks on this subject:--
"The incipient formation of dendritic deposits, which
were formerly regarded as a sign of a truly fossil
condition, is interesting. It has even been supposed that
in diluvial deposits the presence of _dendrites_ might be
regarded as affording a certain mark of distinction
between bones mixed with the diluvium at a somewhat later
period and the true diluvial relics, to which alone it
was supposed that these deposits were confined. But I
have long been convinced that neither can the absence of
_dendrites_ be regarded as indicative of recent age, nor
their presence as sufficient to establish the great
antiquity of the objects upon which they occur. I have
myself noticed upon paper, which could scarcely be more
than a year old, dendritic deposits, which could not be
distinguished from those on fossil bones. Thus I possess
a dog's skull from the Roman colony of the neighbouring
Heddersheim, _Castrum Hadrianum_, which is in no way
distinguishable from the fossil bones from the Frankish
caves; it presents the same colour, and adheres to the
tongue just as they do; so that this character also,
which, at a former meeting of German naturalists at Bonn,
gave rise to amusing scenes between Buckland and
Schmerling, is no longer of any value. In disputed cases,
therefore, the condition of the bone can scarcely afford
the means for determining with certainty whether it be
fossil, that is to say, whether it belong to geological
antiquity or to the historical period."
As we cannot now look upon the primitive world as representing a wholly
different condition of things, from which no transition exists to the
organic life of the present time, the designation of _fossil_, as
applied to _a bone_, has no longer the sense it conveyed in the time of
Cuvier. Sufficient grounds exist for the assumption that man coexisted
with the animals found in the _diluvium_; and many a barbarous race may,
before all historical time, have disappeared, together with the animals
of the ancient world, whilst the races whose organization is improved
have continued the genus. The bones which form the subject of this paper
present characters which, although not decisive as regards a geological
epoch, are, nevertheless, such as indicate a very high antiquity. It may
also be remarked that, common as is the occurrence of diluvial animal
bones in the muddy deposits of caverns, such remains have not hitherto
been met with in the caves of the Neanderthal; and that the bones, which
were covered by a deposit of mud not more than four or five feet thick,
and without any protective covering of stalagmite, have retained the
greatest part of their organic substance.
These circumstances might be adduced against the probability of a
geological antiquity. Nor should we be justified in regarding the
cranial conformation as perhaps representing the most savage primitive
type of the human race, since crania exist among living savages, which,
though not exhibiting such a remarkable conformation of the forehead,
which gives the skull somewhat the aspect of that of the large apes,
still in other respects, as for instance in the greater depth of the
temporal fossæ, the crest-like, prominent temporal ridges, and a
generally less capacious cranial cavity, exhibit an equally low stage of
development. There is no reason for supposing that the deep frontal
hollow is due to any artificial flattening, such as is practised in
various modes by barbarous nations in the Old and New World. The skull
is quite symmetrical, and shows no indication of counter-pressure at the
occiput, whilst, according to Morton, in the Flat-heads of the Columbia,
the frontal and parietal bones are always unsymmetrical. Its
conformation exhibits the sparing development of the anterior part of
the head which has been so often observed in very ancient crania, and
affords one of the most striking proofs of the influence of culture and
civilization on the form of the human skull.
In a subsequent passage, Dr. Schaaffhausen remarks:
"There is no reason whatever for regarding the unusual
development of the frontal sinuses in the remarkable
skull from the Neanderthal as an individual or
pathological deformity; it is unquestionably a typical
race-character, and is physiologically connected with the
uncommon thickness of the other bones of the skeleton,
which exceeds by about one-half the usual proportions.
This expansion of the frontal sinuses, which are
appendages of the air-passages, also indicates an unusual
force and power of endurance in the movements of the
body, as may be concluded from the size of all the ridges
and processes for the attachment of the muscles or bones.
That this conclusion may be drawn from the existence of
large frontal sinuses, and a prominence of the lower
frontal region, is confirmed in many ways by other
observations. By the same characters, according to
Pallas, the wild horse is distinguished from the
domesticated, and, according to Cuvier, the fossil
cave-bear from every recent species of bear, whilst,
according to Roulin, the pig, which has become wild in
America, and regained a resemblance to the wild boar, is
thus distinguished from the same animal in the
domesticated state, as is the chamois from the goat; and,
lastly, the bull-dog, which is characterised by its large
bones and strongly-developed muscles from every other
kind of dog. The estimation of the facial angle, the
determination of which, according to Professor Owen, is
also difficult in the great apes, owing to the very
prominent supra-orbital ridges, in the present case is
rendered still more difficult from the absence both of
the auditory opening and of the nasal spine. But if the
proper horizontal position of the skull be taken from the
remaining portions of the orbital plates, and the
ascending line made to touch the surface of the frontal
bone behind the prominent supra-orbital ridges, the
facial angle is not found to exceed 56°.[47]
Unfortunately, no portions of the facial bones, whose
conformation is so decisive as regards the form and
expression of the head, have been preserved. The cranial
capacity, compared with the uncommon strength of the
corporeal frame, would seem to indicate a small cerebral
development. The skull, as it is, holds about 31 ounces
of millet-seed; and as, from the proportionate size of
the wanting bones, the whole cranial cavity should have
about 6 ounces more added, the contents, were it perfect,
may be taken at 37 ounces. Tiedemann assigns, as the
cranial contents in the Negro, 40, 38, and 35 ounces. The
cranium holds rather more than 36 ounces of water, which
corresponds to a capacity of 1033.24 cubic centimetres.
Huschke estimates the cranial contents of a Negress at
1127 cubic centimetres; of an old Negro at 1146 cubic
centimetres. The capacity of the Malay skulls, estimated
by water, equalled 36, 33 ounces, whilst in the
diminutive Hindoos it falls to as little as 27 ounces."
After comparing the Neanderthal cranium with many others, ancient and
modern, Professor Schaaffhausen concludes thus:--
"But the human bones and cranium from the Neanderthal
exceed all the rest in those peculiarities of
conformation which lead to the conclusion of their
belonging to a barbarous and savage race. Whether the
cavern in which they were found, unaccompanied with any
trace of human art, were the place of their interment, or
whether, like the bones of extinct animals elsewhere,
they had been washed into it, they may still be regarded
as the most ancient memorial of the early inhabitants of
Europe."
Mr. Busk, the translator of Dr. Schaaffhausen's paper, has enabled us to
form a very vivid conception of the degraded character of the
Neanderthal skull, by placing side by side with its outline, that of the
skull of a Chimpanzee, drawn to the same absolute size.
* * * * *
Some time after the publication of the translation of Professor
Schaaffhausen's Memoir, I was led to study the cast of the Neanderthal
cranium with more attention than I had previously bestowed upon it, in
consequence of wishing to supply Sir Charles Lyell with a diagram,
exhibiting the special peculiarities of this skull, as compared with
other human skulls. In order to do this it was necessary to identify,
with precision, those points in the skulls compared which corresponded
anatomically. Of these points, the glabella was obvious enough; but when
I had distinguished another, defined by the occipital protuberance and
superior semicircular line, and had placed the outline of the
Neanderthal skull against that of the Engis skull, in such a position
that the glabella and occipital protuberance of both were intersected by
the same straight line, the difference was so vast and the flattening of
the Neanderthal skull so prodigious (compare Figs. 22 and 24, A), that I
at first imagined I must have fallen into some error. And I was the more
inclined to suspect this, as, in ordinary human skulls, the occipital
protuberance and superior semicircular curved line on the exterior of
the occiput correspond pretty closely with the "lateral sinuses" and the
line of attachment of the tentorium internally. But on the tentorium
rests, as I have said in the preceding Essay, the posterior lobe of the
brain; and hence, the occipital protuberance, and the curved line in
question, indicate, approximately, the lower limits of that lobe. Was it
possible for a human being to have the brain thus flattened and
depressed; or, on the other hand, had the muscular ridges shifted their
position? In order to solve these doubts, and to decide the question
whether the great supraciliary projections did, or did not, arise from
the development of the frontal sinuses, I requested Sir Charles Lyell to
be so good as to obtain for me from Dr. Fuhlrott, the possessor of the
skull, answers to certain queries, and if possible a cast, or at any
rate drawings, or photographs, of the interior of the skull.
[Illustration: FIG. 24.--The skull from the Neanderthal cavern. A. side,
B. front, and C. top view. One-third the natural size. The outlines from
camera lucida drawings, one-half the natural size, by Mr. Busk: the
details from the cast and from Dr. Fuhlrott's photographs. _a_,
glabella; _b_, occipital protuberance; _d_, lambdoidal suture.]
Dr. Fuhlrott replied, with a courtesy and readiness for which I am
infinitely indebted to him, to my inquiries, and furthermore sent three
excellent photographs. One of these gives a side view of the skull, and
from it Fig. 24, A. has been shaded. The second (Fig. 25, A.) exhibits
the wide openings of the frontal sinuses upon the inferior surface of
the frontal part of the skull, into which, Dr. Fuhlrott writes, "a probe
may be introduced to the depth of an inch," and demonstrates the great
extension of the thickened supraciliary ridges beyond the cerebral
cavity. The third, lastly (Fig. 25, B.), exhibits the edge and the
interior of the posterior, or occipital, part of the skull, and shows
very clearly the two depressions for the lateral sinuses, sweeping
inwards towards the middle line of the roof of the skull, to form the
longitudinal sinus. It was clear, therefore, that I had not erred in my
interpretation, and that the posterior lobe of the brain of the
Neanderthal man must have been as much flattened as I suspected it to
be.
[Illustration: FIG. 25.--Drawings from Dr. Fuhlrott's photographs of
parts of the interior of the Neanderthal cranium. A. view of the under
and inner surface of the frontal region, showing the inferior apertures
of the frontal sinuses (_a_). B. corresponding view of the occipital
region of the skull, showing the impressions of the lateral sinuses (_a_
_a_).]
In truth, the Neanderthal cranium has most extraordinary characters. It
has an extreme length of 8 inches, while its breadth is only 5.75
inches, or, in other words, its length is to its breadth as 100: 72. It
is exceedingly depressed, measuring only about 3.4 inches from the
glabello-occipital line to the vertex. The longitudinal arc, measured in
the same way as in the Engis skull, is 12 inches; the transverse arc
cannot be exactly ascertained, in consequence of the absence of the
temporal bones, but was probably about the same, and certainly exceeded
10-1/4 inches. The horizontal circumference is 23 inches. But this great
circumference arises largely from the vast development of the
supraciliary ridges, though the perimeter of the brain case itself is
not small. The large supraciliary ridges give the forehead a far more
retreating appearance than its internal contour would bear out.
To an anatomical eye the posterior part of the skull is even more
striking than the anterior. The occipital protuberance occupies the
extreme posterior end of the skull, when the glabello-occipital line is
made horizontal, and so far from any part of the occipital region
extending beyond it, this region of the skull slopes obliquely upward
and forward, so that the lambdoidal suture is situated well upon the
upper surface of the cranium. At the same time, notwithstanding the
great length of the skull, the sagittal suture is remarkably short
(4-1/2 inches), and the squamosal suture is very straight.
In reply to my questions Dr. Fuhlrott writes that the occipital bone "is
in a state of perfect preservation as far as the upper semicircular
line, which is a very strong ridge, linear at its extremities, but
enlarging towards the middle, where it forms two ridges (bourrelets),
united by a linear continuation, which is slightly depressed in the
middle."
"Below the left ridge the bone exhibits an obliquely inclined surface,
six lines (French) long, and twelve lines wide."
This last must be the surface, the contour of which is shown in Fig. 24,
A, below _b_. It is particularly interesting, as it suggests that,
notwithstanding the flattened condition of the occiput, the posterior
cerebral lobes must have projected considerably beyond the cerebellum,
and as it constitutes one among several points of similarity between the
Neanderthal cranium and certain Australian skulls.
* * * * *
Such are the two best known forms of human cranium, which have been
found in what may be fairly termed a fossil state. Can either be shown
to fill up or diminish, to any appreciable extent, the structural
interval which exists between Man and the man-like Apes? Or, on the
other hand, does neither depart more widely from the average structure
of the human cranium, than normally formed skulls of men are known to do
at the present day?
It is impossible to form any opinion on these questions, without some
preliminary acquaintance with the range of variation exhibited by human
structure in general--a subject which has been but imperfectly studied,
while even of what is known, my limits will necessarily allow me to give
only a very imperfect sketch.
The student of anatomy is perfectly well aware that there is not a
single organ of the human body the structure of which does not vary, to
a greater or less extent, in different individuals. The skeleton varies
in the proportions, and even to a certain extent in the connexions, of
its constituent bones. The muscles which move the bones vary largely in
their attachments. The varieties in the mode of distribution of the
arteries are carefully classified, on account of the practical
importance of a knowledge of their shiftings to the surgeon. The
characters of the brain vary immensely, nothing being less constant than
the form and size of the cerebral hemispheres, and the richness of the
convolutions upon their surface, while the most changeable structures of
all in the human brain, are exactly those on which the unwise attempt
has been made to base the distinctive characters of humanity, viz. the
posterior cornu of the lateral ventricle, the hippocampus minor, and the
degree of projection of the posterior lobe beyond the cerebellum.
Finally, as all the world knows, the hair and skin of human beings may
present the most extraordinary diversities in colour and in texture.
So far as our present knowledge goes, the majority of the structural
varieties to which allusion is here made, are individual. The ape-like
arrangement of certain muscles which is occasionally met with[48] in the
white races of mankind, is not known to be more common among Negroes or
Australians: nor because the brain of the Hottentot Venus was found to
be smoother, to have its convolutions more symmetrically disposed, and
to be, so far, more ape-like than that of ordinary Europeans, are we
justified in concluding a like condition of the brain to prevail
universally among the lower races of mankind, however probable that
conclusion may be.
We are, in fact, sadly wanting in information respecting the disposition
of the soft and destructible organs of every Race of Mankind but our
own; and even of the skeleton, our Museums are lamentably deficient in
every part but the cranium. Skulls enough there are, and since the time
when Blumenbach and Camper first called attention to the marked and
singular differences which they exhibit, skull collecting and skull
measuring has been a zealously pursued branch of Natural History, and
the results obtained have been arranged and classified by various
writers, among whom the late active and able Retzius must always be the
first named.
Human skulls have been found to differ from one another, not merely in
their absolute size and in the absolute capacity of the brain case, but
in the proportions which the diameters of the latter bear to one
another; in the relative size of the bones of the face (and more
particularly of the jaws and teeth) as compared with those of the skull;
in the degree to which the upper jaw (which is of course followed by the
lower) is thrown backwards and downwards under the forepart of the brain
case, or forwards and upwards in front of and beyond it. They differ
further in the relations of the transverse diameter of the face, taken
through the cheek bones, to the transverse diameter of the skull; in the
more rounded or more gable-like form of the roof of the skull, and in
the degree to which the hinder part of the skull is flattened or
projects beyond the ridge, into and below which, the muscles of the neck
are inserted.
In some skulls the brain case may be said to be "_round_," the extreme
length not exceeding the extreme breadth by a greater proportion than
100 to 80, while the difference may be much less.[49] Men possessing
such skulls were termed by Retzius "_brachycephalic_," and the skull of
a Calmuck, of which a front and side view (reduced outline copies of
which are given in Figure 26) are depicted by Von Baer in his excellent
"Crania selecta," affords a very admirable example of that kind of
skull. Other skulls, such as that of a Negro copied in Fig. 27 from Mr.
Busk's "Crania typica," have a very different, greatly elongated form,
and may be termed "_oblong_." In this skull the extreme length is to the
extreme breadth as 100 to not more than 67, and the transverse diameter
of the human skull may fall below even this proportion. People having
such skulls were called by Retzius "_dolichocephalic_."
The most cursory glance at the side views of these two skulls will
suffice to prove that they differ, in another respect, to a very
striking extent. The profile of the face of the Calmuck is almost
vertical, the facial bones being thrown downwards and under the fore
part of the skull. The profile of the face of the Negro, on the other
hand, is singularly inclined, the front part of the jaws projecting far
forward beyond the level of the fore part of the skull. In the former
case the skull is said to be "_orthognathous_" or straight-jawed; in the
latter, it is called "_prognathous_," a term which has been rendered,
with more force than elegance, by the Saxon equivalent,--"snouty."
Various methods have been devised in order to express with some accuracy
the degree of prognathism or orthognathism of any given skull; most of
these methods being essentially modifications of that devised by Peter
Camper, in order to attain what he called the "facial angle."
[Illustration: FIG. 26.--Side and front views of the round and
orthognathous skull of a Calmuck after Von Baer. One-third the natural
size.]
But a little consideration will show that any "facial angle" that has
been devised, can be competent to express the structural modifications
involved in prognathism and orthognathism, only in a rough and general
sort of way. For the lines, the intersection of which forms the facial
angle, are drawn through points of the skull, the position of each of
which is modified by a number of circumstances, so that the angle
obtained is a complex resultant of all these circumstances, and is not
the expression of any one definite organic relation of the parts of the
skull.
I have arrived at the conviction that no comparison of crania is worth
very much, that is not founded upon the establishment of a relatively
fixed base line, to which the measurements, in all cases, must be
referred. Nor do I think it is a very difficult matter to decide what
that base line should be. The parts of the skull, like those of the rest
of the animal framework, are developed in succession: the base of the
skull is formed before its sides and roof; it is converted into
cartilage earlier and more completely than the sides and roof: and the
cartilaginous base ossifies, and becomes soldered into one piece long
before the roof. I conceive then that the base of the skull may be
demonstrated developmentally to be its relatively fixed part, the roof
and sides being relatively moveable.
The same truth is exemplified by the study of the modifications which
the skull undergoes in ascending from the lower animals up to man.
In such a mammal as a Beaver (Fig. 28), a line (_a_. _b_.) drawn through
the bones, termed basioccipital, basisphenoid, and presphenoid, is very
long in proportion to the extreme length of the cavity which contains
the cerebral hemispheres (_g_. _h_.). The plane of the occipital foramen
(_b_. _c_.) forms a slightly acute angle with this "basicranial axis,"
while the plane of the tentorium (_i_. _T_.) is inclined at rather more
than 90° to the "basicranial axis"; and so is the plane of the
perforated plate (_a_. _d_.) by which the filaments of the olfactory
nerve leave the skull. Again, a line drawn through the axis of the face,
between the bones called ethmoid and vomer--the "basifacial axis" (_f_.
_e_.) forms an exceedingly obtuse angle, where, when produced, it cuts
the "basicranial axis."
[Illustration: FIG. 27.--Oblong and prognathous skull of a Negro; side
and front views. One-third of the natural size.]
If the angle made by the line _b_. _c_. with _a_. _b_., be called the
"occipital angle," and the angle made by the line _a_. _d_. with _a_.
_b_. be termed the "olfactory angle," and that made by _i_. _T_. with
_a_. _b_. the "tentorial angle," then all these, in the mammal in
question, are nearly right angles, varying between 80° and 110°. The
angle _e_. _f_. _b_., or that made by the cranial with the facial axis,
and which may be termed the "cranio-facial angle," is extremely obtuse,
amounting, in the case of the Beaver, to at least 150°.
But if a series of sections of mammalian skulls, intermediate between a
Rodent and a Man (Fig. 28), be examined, it will be found that in the
higher crania the basicranial axis becomes shorter relatively to the
cerebral length; that the "olfactory angle" and "occipital angle" become
more obtuse; and that the "cranio-facial angle" becomes more acute by
the bending down, as it were, of the facial axis upon the cranial axis.
At the same time, the roof of the cranium becomes more and more arched,
to allow of the increasing height of the cerebral hemispheres, which is
eminently characteristic of man, as well as of that backward extension,
beyond the cerebellum, which reaches its maximum in the South American
Monkeys. So that, at last, in the human skull (Fig. 29), the cerebral
length is between twice and thrice as great as the length of the
basicranial axis; the olfactory plane is 20° or 30° on the _under_ side
of that axis; the occipital angle, instead of being less than 90°, is as
much as 150° or 160°; the cranio-facial angle may be 90° or less, and
the vertical height of the skull may have a large proportion to its
length.
It will be obvious, from an inspection of the diagrams, that the
basicranial axis is, in the ascending series of Mammalia, a relatively
fixed line, on which the bones of the sides and roof of the cranial
cavity, and of the face, may be said to revolve downwards and forwards
or backwards, according to their position. The arc described by any one
bone or plane, however, is not by any means always in proportion to the
arc described by another.
Now comes the important question, can we discern, between the lowest and
the highest forms of the human cranium anything answering, in however
slight a degree, to this revolution of the side and roof bones of the
skull upon the basicranial axis observed upon so great a scale in the
mammalian series? Numerous observations lead me to believe that we must
answer this question in the affirmative.
[Illustration: FIG. 28.--Longitudinal and vertical sections of the
skulls of a Beaver (_Castor Canadensis_), a Lemur (_L. Catta_), and a
Baboon (_Cynocephalus Papio_), _a b_, the basicranial axis; _b c_, the
occipital plane; _i T_, the tentorial plane; _a d_, the olfactory plane;
_f e_, the basifacial axis; _c b a_, occipital angle; _T i a_, tentorial
angle; _d a b_, olfactory angle; _e f b_, cranio-facial angle; _g h_,
extreme length of the cavity which lodges the cerebral hemispheres or
"cerebral length." The length of the basicranial axis as to this length,
or, in other words, the proportional length of the line _g h_ to that of
_a b_ taken as 100, in the three skulls, is as follows:--Beaver 70 to
100; Lemur 119 to 100; Baboon 144 to 100. In an adult male Gorilla the
cerebral length is as 170 to the basicranial axis taken as 100, in the
Negro (Fig. 29) as 236 to 100. In the Constantinople skull (Fig. 29) as
266 to 100. The cranial difference between the highest Ape's skull and
the lowest Man's is therefore very strikingly brought out by these
measurements.
In the diagram of the Baboon's skull the dotted lines _d^1d^2_, &c.,
give the angles of the Lemur's and Beaver's skull, as laid down upon the
basicranial axis of the Baboon. The line _a b_ has the same length in
each diagram.]
The diagrams in Figure 29 are reduced from very carefully made diagrams
of sections of four skulls, two round and orthognathous, two long and
prognathous, taken longitudinally and vertically, through the middle.
The sectional diagrams have then been superimposed, in such a manner,
that the basal axes of the skulls coincide by their anterior ends, and
in their direction. The deviations of the rest of the contours (which
represent the interior of the skulls only) show the differences of the
skulls from one another, when these axes are regarded as relatively
fixed lines.
The dark contours are those of an Australian and of a Negro skull: the
light contours are those of a Tartar skull, in the Museum of the Royal
College of Surgeons; and of a well developed round skull from a cemetery
in Constantinople, of uncertain race, in my own possession.
It appears, at once, from these views, that the prognathous skulls, so
far as their jaws are concerned, do really differ from the orthognathous
in much the same way as, though to a far less degree than, the skulls of
the lower mammals differ from those of Man. Furthermore, the plane of
the occipital foramen (_b c_) forms a somewhat smaller angle with the
axis in these particular prognathous skulls than in the orthognathous;
and the like may be slightly true of the perforated plate of the
ethmoid--though this point is not so clear. But it is singular to remark
that, in another respect, the prognathous skulls are less ape-like than
the orthognathous, the cerebral cavity projecting decidedly more beyond
the anterior end of the axis in the prognathous, than in the
orthognathous, skulls.
It will be observed that these diagrams reveal an immense range of
variation in the capacity and relative proportion to the cranial axis,
of the different regions of the cavity which contains the brain, in the
different skulls. Nor is the difference in the extent to which the
cerebral overlaps the cerebellar cavity less singular. A round skull
(Fig. 29, _Const._) may have a greater posterior cerebral projection
than a long one (Fig. 29, _Negro_).
[Illustration: FIG. 29.--Sections of orthognathous (light contour) and
prognathous (dark contour) skulls, one-third of the natural size. _a b_,
Basicranial axis; _b c_, _b´ c´_, plane of the occipital foramen; _d
d´_, hinder end of the palatine bone; _e e´_, front end of the upper
jaw; _TT_´, insertion of the tentorium.]
Until human crania have been largely worked out in a manner similar to
that here suggested--until it shall be an opprobrium to an ethnological
collection to possess a single skull which is not bisected
longitudinally--until the angles and measurements here mentioned,
together with a number of others of which I cannot speak in this place,
are determined, and tabulated with reference to the basicranial axis as
unity, for large numbers of skulls of the different races of Mankind, I
do not think we shall have any very safe basis for that ethnological
craniology which aspires to give the anatomical characters of the crania
of the different Races of Mankind.
At present, I believe that the general outlines of what may be safely
said upon that subject may be summed up in a very few words. Draw a line
on a globe from the Gold Coast in Western Africa to the steppes of
Tartary. At the southern and western end of that line there live the
most dolichocephalic, prognathous, curly-haired, dark-skinned of
men--the true Negroes. At the northern and eastern end of the same line
there live the most brachycephalic, orthognathous, straight-haired,
yellow-skinned of men--the Tartars and Calmucks. The two ends of this
imaginary line are indeed, so to speak, ethnological antipodes. A line
drawn at right angles, or nearly so, to this polar line through Europe
and Southern Asia to Hindostan, would give us a sort of equator, around
which round-headed, oval-headed, and oblong-headed, prognathous and
orthognathous, fair and dark races--but none possessing the excessively
marked characters of Calmuck or Negro--group themselves.
It is worthy of notice that the regions of the antipodal races are
antipodal in climate, the greatest contrast the world affords, perhaps,
being that between the damp, hot, steaming, alluvial coast plains of the
West Coast of Africa and the arid, elevated steppes and plateaux of
Central Asia, bitterly cold in winter, and as far from the sea as any
part of the world can be.
From Central Asia eastward to the Pacific Islands and subcontinents on
the one hand, and to America on the other, brachycephaly and
orthognathism gradually diminish, and are replaced by dolichocephaly and
prognathism, less, however, on the American Continent (throughout the
whole length of which a rounded type of skull prevails largely, but not
exclusively)[50] than in the Pacific region, where, at length, on the
Australian Continent and in the adjacent islands, the oblong skull, the
projecting jaws, and the dark skin reappear; with so much departure, in
other respects, from the Negro type, that ethnologists assign to these
people the special title of "Negritoes."
The Australian skull is remarkable for its narrowness and for the
thickness of its walls, especially in the region of the supraciliary
ridge, which is frequently, though not by any means invariably, solid
throughout, the frontal sinuses remaining undeveloped. The nasal
depression, again, is extremely sudden, so that the brows overhang and
give the countenance a particularly lowering, threatening expression.
The occipital region of the skull, also, not unfrequently becomes less
prominent; so that it not only fails to project beyond a line drawn
perpendicular to the hinder extremity of the glabello-occipital line,
but even, in some cases, begins to shelve away from it, forwards, almost
immediately. In consequence of this circumstance, the parts of the
occipital bone which lie above and below the tuberosity make a much more
acute angle with one another than is usual, whereby the hinder part of
the base of the skull appears obliquely truncated. Many Australian
skulls have a considerable height, quite equal to that of the average of
any other race, but there are others in which the cranial roof becomes
remarkably depressed, the skull, at the same time, elongating so much
that, probably, its capacity is not diminished. The majority of skulls
possessing these characters, which I have seen, are from the
neighbourhood of Port Adelaide in South Australia, and have been used by
the natives as water vessels; to which end the face has been knocked
away, and a string passed through the vacuity and the occipital foramen,
so that the skull was suspended by the greater part of its basis.
Figure 30 represents the contour of a skull of this kind from Western
Port, with the jaw attached, and of the Neanderthal skull, both reduced
to one-third of the size of nature. A small additional amount of
flattening and lengthening, with a corresponding increase of the
supraciliary ridge, would convert the Australian brain case into a form
identical with that of the aberrant fossil.
* * * * *
[Illustration: FIG. 30.--An Australian skull from Western Port, in the
Museum of the Royal College of Surgeons, with the contour of the
Neanderthal skull. Both reduced to one-third the natural size.]
And now, to return to the fossil skulls, and to the rank which they
occupy among, or beyond, these existing varieties of cranial
conformation. In the first place, I must remark, that, as Professor
Schmerling well observed (_supra_, p. 114) in commenting upon the Engis
skull, the formation of a safe judgment upon the question is greatly
hindered by the absence of the jaws from both the crania, so that there
is no means of deciding, with certainty, whether they were more or less
prognathous than the lower existing races of mankind. And yet, as we
have seen, it is more in this respect than any other, that human skulls
vary, towards and from, the brutal type--the brain case of an average
dolichocephalic European differing far less from that of a Negro, for
example, than his jaws do. In the absence of the jaws, then, any
judgment on the relations of the fossil skulls to recent Races must be
accepted with a certain reservation.
But taking the evidence as it stands, and turning first to the Engis
skull, I confess I can find no character in the remains of that cranium
which, if it were a recent skull, would give any trustworthy clue as to
the Race to which it might appertain. Its contours and measurements
agree very well with those of some Australian skulls which I have
examined--and especially has it a tendency towards that occipital
flattening, to the great extent of which, in some Australian skulls, I
have alluded. But all Australian skulls do not present this flattening,
and the supraciliary ridge of the Engis skull is quite unlike that of
the typical Australians.
On the other hand, its measurements agree equally well with those of
some European skulls. And assuredly, there is no mark of degradation
about any part of its structure. It is, in fact, a fair average human
skull, which might have belonged to a philosopher, or might have
contained the thoughtless brains of a savage.
The case of the Neanderthal skull is very different. Under whatever
aspect we view this cranium, whether we regard its vertical depression,
the enormous thickness of its supraciliary ridges, its sloping occiput,
or its long and straight squamosal suture, we meet with ape-like
characters, stamping it as the most pithecoid of human crania yet
discovered. But Professor Schaaffhausen states (_supra_, p. 122), that
the cranium, in its present condition, holds 1033.24 cubic centimetres
of water, or about 63 cubic inches, and as the entire skull could hardly
have held less than an additional 12 cubic inches, its capacity may be
estimated at about 75 cubic inches, which is the average capacity given
by Morton for Polynesian and Hottentot skulls.
[Illustration: FIG. 31.--Ancient Danish skull from a tumulus at Borreby;
one-third of the natural size. From a camera lucida drawing by Mr.
Busk.]
So large a mass of brain as this, would alone suggest that the pithecoid
tendencies, indicated by this skull, did not extend deep into the
organization; and this conclusion is borne out by the dimensions of the
other bones of the skeleton given by Professor Schaaffhausen, which show
that the absolute height and relative proportions of the limbs, were
quite those of an European of middle stature. The bones are indeed
stouter, but this and the great development of the muscular ridges noted
by Dr. Schaaffhausen, are characters to be expected in savages. The
Patagonians, exposed without shelter or protection to a climate possibly
not very dissimilar from that of Europe at the time during which the
Neanderthal man lived, are remarkable for the stoutness of their limb
bones.
In no sense, then, can the Neanderthal bones be regarded as the remains
of a human being intermediate between Men and Apes. At most, they
demonstrate the existence of a man whose skull may be said to revert
somewhat towards the pithecoid type--just as a Carrier, or a Pouter, or
a Tumbler, may sometimes put on the plumage of its primitive stock, the
_Columba livia_. And indeed, though truly the most pithecoid of known
human skulls, the Neanderthal cranium is by no means so isolated as it
appears to be at first, but forms, in reality, the extreme term of a
series leading gradually from it to the highest and best developed of
human crania. On the one hand, it is closely approached by the flattened
Australian skulls, of which I have spoken, from which other Australian
forms lead us gradually up to skulls having very much the type of the
Engis cranium. And, on the other hand, it is even more closely affined
to the skulls of certain ancient people who inhabited Denmark during the
"stone period," and were probably either contemporaneous with, or later
than, the makers of the "refuse heaps," or "Kjokkenmöddings" of that
country.
The correspondence between the longitudinal contour of the Neanderthal
skull and that of some of those skulls from the tumuli at Borreby, very
accurate drawings of which have been made by Mr. Busk, is very close.
The occiput is quite as retreating, the supraciliary ridges are nearly
as prominent, and the skull is as low. Furthermore, the Borreby skull
resembles the Neanderthal form more closely than any of the Australian
skulls do, by the much more rapid retrocession of the forehead. On the
other hand, the Borreby skulls are all somewhat broader, in proportion
to their length, than the Neanderthal skull, while some attain that
proportion of breadth to length (80: 100) which constitutes
brachycephaly.
* * * * *
In conclusion, I may say, that the fossil remains of Man hitherto
discovered do not seem to me to take us appreciably nearer to that
lower pithecoid form, by the modification of which he has, probably,
become what he is. And considering what is now known of the most ancient
races of men; seeing that they fashioned flint axes and flint knives and
bone-skewers, of much the same pattern as those fabricated by the lowest
savages at the present day, and that we have every reason to believe the
habits and modes of living of such people to have remained the same from
the time of the Mammoth and the tichorhine Rhinoceros till now, I do not
know that this result is other than might be expected.
Where, then, must we look for primæval Man? Was the oldest _Homo
sapiens_ pliocene or miocene, or yet more ancient? In still older strata
do the fossilized bones of an Ape more anthropoid, or a Man more
pithecoid, than any yet known await the researches of some unborn
paleontologist?
Time will show. But, in the meanwhile, if any form of the doctrine of
progressive development is correct, we must extend by long epochs the
most liberal estimate that has yet been made of the antiquity of Man.
FOOTNOTES:
[38] Decas Collectionis suæ craniorum diversarum gentium illustrata.
Gottingæ, 1790-1820.
[39] In a subsequent passage, Schmerling remarks upon the occurrence of
an incisor tooth "of enormous size" from the caverns of Engihoul. The
tooth figured is somewhat long, but its dimensions do not appear to me
to be otherwise remarkable.
[40] The figure of this clavicle measures 5 inches from end to end in a
straight line--so that the bone is rather a small than a large one.
[41] ON THE CRANIA OF THE MOST ANCIENT RACES OF MAN. By Professor D.
Schaaffhausen, of Bonn. (From Müller's Archiv., 1858, p. 453.) With
Remarks, and original Figures, taken from a Cast of the Neanderthal
Cranium. By George Busk, F.R.S., &c. Natural History Review, April,
1861.
[42] Verhandl. d. Naturhist. Vereins der preuss. Rheinlande und
Westphalens., xiv. Bonn, 1857.
[43] Ib. Correspondenzblatt. No. 2.
[44] This, Mr. Busk has pointed out, is probably the notch for the
frontal nerve.
[45] The numbers in brackets are those which I should assign to the
different measures, as taken from the plaster cast.--G. B.
[46] Verh. des Naturhist. Vereins in Bonn, xiv. 1857.
[47] Estimating the facial angle in the way suggested, on the cast I
should place it at 64° to 67°.--G. B.
[48] See an excellent Essay by Mr. Church on the Myology of the Orang,
in the Natural History Review, for 1861.
[49] In no normal human skull does the breadth of the brain-case exceed
its length.
[50] See Dr. D. Wilson's valuable paper "On the supposed prevalence of
one Cranial Type throughout the American aborigines."--Canadian Journal,
vol. ii., 1857.
IV
THE PRESENT CONDITION OF ORGANIC
NATURE.
When it was my duty to consider what subject I would select for the six
lectures which I shall now have the pleasure of delivering to you, it
occurred to me that I could not do better than endeavour to put before
you in a true light, or in what I might perhaps with more modesty call,
that which I conceive myself to be the true light, the position of a
book which has been more praised and more abused, perhaps, than any book
which has appeared for some years;--I mean Mr. Darwin's work on the
"Origin of Species." That work, I doubt not, many of you have read; for
I know the inquiring spirit which is rife among you. At any rate, all of
you will have heard of it,--some by one kind of report and some by
another kind of report; the attention of all and the curiosity of all
have been probably more or less excited on the subject of that work. All
I can do, and all I shall attempt to do, is to put before you that kind
of judgment which has been formed by a man, who, of course, is liable to
judge erroneously; but at any rate, of one whose business and profession
it is to form judgments upon questions of this nature.
And here, as it will always happen when dealing with an extensive
subject, the greater part of my course--if, indeed, so small a number of
lectures can be properly called a course--must be devoted to preliminary
matters, or rather to a statement of those facts and of those principles
which the work itself dwells upon, and brings more or less directly
before us. I have no right to suppose that all or any of you are
naturalists; and even if you were, the misconceptions and
misunderstandings prevalent even among naturalists on these matters
would make it desirable that I should take the course I now propose to
take,--that I should start from the beginning,--that I should endeavour
to point out what is the existing state of the organic world--that I
should point out its past condition,--that I should state what is the
precise nature of the undertaking which Mr. Darwin has taken in hand;
that I should endeavour to show you what are the only methods by which
that undertaking can be brought to an issue, and to point out to you how
far the author of the work in question has satisfied those conditions,
how far he has not satisfied them, how far they are satisfiable by man,
and how far they are not satisfiable by man.
To-night, in taking up the first part of the question, I shall endeavour
to put before you a sort of broad notion of our knowledge of the
condition of the living world. There are many ways of doing this. I
might deal with it pictorially and graphically. Following the example of
Humboldt in his "Aspects of Nature," I might endeavour to point out the
infinite variety of organic life in every mode of its existence, with
reference to the variations of climate and the like; and such an attempt
would be fraught with interest to us all; but considering the subject
before us, such a course would not be that best calculated to assist us.
In an argument of this kind we must go further and dig deeper into the
matter; we must endeavour to look into the foundations of living Nature,
if I may so say, and discover the principles involved in some of her
most secret operations. I propose, therefore, in the first place, to
take some ordinary animal with which you are all familiar, and, by
easily comprehensible and obvious examples drawn from it, to show what
are the kind of problems which living beings in general lay before us;
and I shall then show you that the same problems are laid open to us by
all kinds of living beings. But, first, let me say in what sense I have
used the words "organic nature." In speaking of the causes which lead to
our present knowledge of organic nature, I have used it almost as an
equivalent of the word "living," and for this reason,--that in almost
all living beings you can distinguish several distinct portions set
apart to do particular things and work in a particular way. These are
termed "organs," and the whole together is called "organic." And as it
is universally characteristic of them, the term "organic" has been very
conveniently employed to denote the whole of living nature,--the whole
of the plant world, and the whole of the animal world.
Few animals can be more familiar to you than that whose skeleton is
shown on our diagram. You need not bother yourselves with this "_Equus
caballus_" written under it; that is only the Latin name of it, and does
not make it any better. It simply means the common Horse. Suppose we
wish to understand all about the Horse. Our first object must be to
study the structure of the animal. The whole of his body is inclosed
within a hide, a skin covered with hair; and if that hide or skin be
taken off, we find a great mass of flesh, or what is technically called
muscle, being the substance which by its power of contraction enables
the animal to move. These muscles move the hard parts one upon the
other, and so give that strength and power of motion which renders the
Horse so useful to us in the performance of those services in which we
employ him.
And then, on separating and removing the whole of this skin and flesh,
you have a great series of bones, hard structures, bound together with
ligaments, and forming the skeleton which is represented here.
[Illustration: FIG. 32.]
In that skeleton there are a number of parts to be recognized. The long
series of bones, beginning from the skull and ending in the tail, is
called the spine, and those in front are the ribs; and then there are
two pairs of limbs, one before and one behind; and there are what we all
know as the fore-legs and the hind-legs. If we pursue our researches
into the interior of this animal, we find within the framework of the
skeleton a great cavity, or rather, I should say, two great
cavities,--one cavity beginning in the skull and running through the
neck-bones, along the spine, and ending in the tail, containing the
brain and the spinal marrow, which are extremely important organs. The
second great cavity, commencing with the mouth, contains the gullet, the
stomach, the long intestine, and all the rest of those internal
apparatus which are essential for digestion; and then in the same great
cavity, there are lodged the heart and all the great vessels going from
it; and, besides that, the organs of respiration--the lungs; and then
the kidneys, and the organs of reproduction, and so on. Let us now
endeavour to reduce this notion of a horse that we now have, to some
such kind of simple expression as can be at once, and without
difficulty, retained in the mind, apart from all minor details. If I
make a transverse section, that is, if I were to saw a dead horse
across, I should find that, if I left out the details, and supposing I
took my section through the anterior region, and through the fore-limbs,
I should have here this kind of section of the body (Fig. 32). Here
would be the upper part of the animal--that great mass of bones that we
spoke of as the spine (_a_, Fig. 32). Here I should have the alimentary
canal (_b_, Fig. 32). Here I should have the heart (_c_, Fig. 32); and
then you see, there would be a kind of double tube, the whole being
inclosed within the hide; the spinal marrow would be placed in the upper
tube (_a_, Fig. 32), and in the lower tube (_d d_, Fig. 32), there would
be the alimentary canal (_b_), and the heart (_c_); and here I shall
have the legs proceeding from each side. For simplicity's sake, I
represent them merely as stumps (_e e_, Fig. 32). Now that is a
horse--as mathematicians would say--reduced to its most simple
expression. Carry that in your minds, if you please, as a simplified
idea of the structure of the Horse. The considerations which I have now
put before you belong to what we technically call the "Anatomy" of the
Horse. Now, suppose we go to work upon these several parts,--flesh and
hair, and skin and bone, and lay open these various organs with our
scalpels, and examine them by means of our magnifying-glasses, and see
what we can make of them. We shall find that the flesh is made up of
bundles of strong fibres. The brain and nerves, too, we shall find, are
made up of fibres, and these queer-looking things that are called
ganglionic corpuscles. If we take a slice of the bone and examine it, we
shall find that it is very like this diagram of a section of the bone of
an ostrich, though differing, of course, in some details; and if we take
any part whatsoever of the tissue, and examine it, we shall find it all
has a minute structure, visible only under the microscope. All these
parts constitute microscopic anatomy or "Histology." These parts are
constantly being changed; every part is constantly growing, decaying,
and being replaced during the life of the animal. The tissue is
constantly replaced by new material; and if you go back to the young
state of the tissue in the case of muscle, or in the case of skin, or
any of the organs I have mentioned, you will find that they all come
under the same condition. Every one of these microscopic filaments and
fibres (I now speak merely of the general character of the whole
process)--every one of these parts--could be traced down to some
modification of a tissue which can be readily divided into little
particles of fleshy matter, of that substance which is composed of the
chemical elements, carbon, hydrogen, oxygen, and nitrogen, having such a
shape as this (Fig. 33). These particles, into which all primitive
tissues break up, are called cells. If I were to make a section of a
piece of the skin of my hand, I should find that it was made up of these
cells. If I examine the fibres which form the various organs of all
living animals, I should find that all of them, at one time or other,
had been formed out of a substance consisting of similar elements; so
that you see, just as we reduced the whole body in the gross to that
sort of simple expression given in Fig. 32, so we may reduce the whole
of the microscopic structural elements to a form of even greater
simplicity; just as the plan of the whole body may be so represented in
a sense (Fig. 32), so the primary structure of every tissue may be
represented by a mass of cells (Fig. 33).
[Illustration: FIG. 33.]
Having thus, in this sort of general way, sketched to you what I may
call, perhaps, the architecture of the body of the Horse, (what we term
technically its Morphology,) I must now turn to another aspect. A horse
is not a mere dead structure: it is an active, living, working machine.
Hitherto we have, as it were, been looking at a steam-engine with the
fires out, and nothing in the boiler; but the body of the living animal
is a beautifully-formed active machine, and every part has its different
work to do in the working of that machine, which is what we call its
life. The Horse, if you see him after his day's work is done, is
cropping the grass in the fields, as it may be, or munching the oats in
his stable. What is he doing? His jaws are working as a mill--and a very
complex mill too--grinding the corn, or crushing the grass to a pulp. As
soon as that operation has taken place, the food is passed down to the
stomach, and there it is mixed with the chemical fluid called the
gastric juice, a substance which has the peculiar property of making
soluble and dissolving out the nutritious matter in the grass, and
leaving behind those parts which are not nutritious; so that you have,
first, the mill, then a sort of chemical digester; and then the food,
thus partially dissolved, is carried back by the muscular contractions
of the intestines into the hinder parts of the body, while the soluble
portions are taken up into the blood. The blood is contained in a vast
system of pipes, spreading through the whole body, connected with a
force-pump,--the heart,--which, by its position and by the contractions
of its valves, keeps the blood constantly circulating in one direction,
never allowing it to rest; and then, by means of this circulation of the
blood, laden as it is with the products of digestion, the skin, the
flesh, the hair, and every other part of the body, draws from it that
which it wants, and every one of these organs derives those materials
which are necessary to enable it to do its work.
The action of each of these organs, the performance of each of these
various duties, involve in their operation a continual absorption of
the matters necessary for their support, from the blood, and a constant
formation of waste products, which are returned to the blood, and
conveyed by it to the lungs and the kidneys, which are organs that have
allotted to them the office of extracting, separating, and getting rid
of these waste products; and thus the general nourishment, labour, and
repair of the whole machine is kept up with order and regularity. But
not only is it a machine which feeds and appropriates to its own support
the nourishment necessary to its existence--it is an engine for
locomotive purposes. The Horse desires to go from one place to another;
and to enable it to do this, it has those strong contractile bundles of
muscles attached to the bones of its limbs, which are put in motion by
means of a sort of telegraphic apparatus formed by the brain and the
great spinal cord running through the spine or backbone; and to this
spinal cord are attached a number of fibres termed nerves, which proceed
to all parts of the structure. By means of these the eyes, nose, tongue,
and skin--all the organs of perception--transmit impressions or
sensations to the brain, which acts as a sort of great central
telegraph-office, receiving impressions and sending messages to all
parts of the body, and putting in motion the muscles necessary to
accomplish any movement that may be desired. So that you have here an
extremely complex and beautifully-proportioned machine, with all its
parts working harmoniously together towards one common object--the
preservation of the life of the animal.
Now, note this: the Horse makes up its waste by feeding, and its food is
grass or oats, or perhaps other vegetable products; therefore, in the
long run, the source of all this complex machinery lies in the vegetable
kingdom. But where does the grass, or the oat, or any other plant,
obtain this nourishing food-producing material? At first it is a little
seed, which soon begins to draw into itself from the earth and the
surrounding air matters which in themselves contain no vital properties
whatever; it absorbs into its own substance water, an inorganic body; it
draws into its substance carbonic acid, an inorganic matter; and
ammonia, another inorganic matter, found in the air; and then, by some
wonderful chemical process, the details of which chemists do not yet
understand, though they are near foreshadowing them, it combines them
into one substance, which is known to us as "Protein," a complex
compound of carbon, hydrogen, oxygen, and nitrogen, which alone
possesses the property of manifesting vitality and of permanently
supporting animal life. So that, you see, the waste products of the
animal economy, the effete materials which are continually being thrown
off by all living beings, in the form of organic matters, are constantly
replaced by supplies of the necessary repairing and rebuilding materials
drawn from the plants, which in their turn manufacture them, so to
speak, by a mysterious combination of those same inorganic materials.
Let us trace out the history of the Horse in another direction. After a
certain time, as the result of sickness or disease, the effect of
accident, or the consequence of old age, sooner or later, the animal
dies. The multitudinous operations of this beautiful mechanism flag in
their performance, the Horse loses its vigour, and after passing through
the curious series of changes comprised in its formation and
preservation, it finally decays, and ends its life by going back into
that inorganic world from which all but an inappreciable fraction of its
substance was derived. Its bones become mere carbonate and phosphate of
lime; the matter of its flesh, and of its other parts, becomes, in the
long run, converted into carbonic acid, into water, and into ammonia.
You will now, perhaps, understand the curious relation of the animal
with the plant, of the organic with the inorganic world, which is shown
in this diagram.
The plant gathers these inorganic materials together and makes them up
into its own substance. The animal eats the plant and appropriates the
nutritious portions to its own sustenance, rejects and gets rid of the
useless matters; and, finally, the animal itself dies, and its whole
body is decomposed and returned into the inorganic world. There is thus
a constant circulation from one to the other, a continual formation of
organic life from inorganic matters, and as constant a return of the
matter of living bodies to the inorganic world; so that the materials
of which our bodies are composed are largely, in all probability, the
substances which constituted the matter of long extinct creations, but
which have in the interval constituted a part of the inorganic world.
[Illustration: INORGANIC WORLD.
VEGETABLE WORLD. ANIMAL WORLD.
FIG. 34.]
Thus we come to the conclusion, strange at first sight, that the MATTER
constituting the living world is identical with that which forms the
inorganic world. And not less true is it that, remarkable as are the
powers or, in other words, as are the FORCES which are exerted by living
beings, yet all these forces are either identical with those which exist
in the inorganic world, or they are convertible into them; I mean in
just the same sense as the researches of physical philosophers have
shown that heat is convertible into electricity, that electricity is
convertible into magnetism, magnetism into mechanical force or chemical
force, and any one of them with the other, each being measurable in
terms of the other,--even so, I say, that great law is applicable to the
living world. Consider why is the skeleton of this horse capable of
supporting the masses of flesh and the various organs forming the living
body, unless it is because of the action of the same forces of cohesion
which combines together the particles of matter composing this piece of
chalk? What is there in the muscular contractile power of the animal
but the force which is expressible, and which is in a certain sense
convertible, into the force of gravity which it overcomes? Or, if you go
to more hidden processes, in what does the process of digestion differ
from those processes which are carried on in the laboratory of the
chemist? Even if we take the most recondite and most complex operations
of animal life--those of the nervous system, these of late years have
been shown to be--I do not say identical in any sense with the
electrical processes--but this has been shown, that they are in some way
or other associated with them; that is to say, that every amount of
nervous action is accompanied by a certain amount of electrical
disturbance in the particles of the nerves in which that nervous action
is carried on. In this way the nervous action is related to electricity
in the same way that heat is related to electricity; and the same sort
of argument which demonstrates the two latter to be related to one
another shows that the nervous forces are correlated to electricity; for
the experiments of M. Dubois Reymond and others have shown that whenever
a nerve is in a state of excitement, sending a message to the muscles or
conveying an impression to the brain, there is a disturbance of the
electrical condition of that nerve which does not exist at other times;
and there are a number of other facts and phenomena of that sort; so
that we come to the broad conclusion that not only as to living matter
itself, but as to the forces that matter exerts, there is a close
relationship between the organic and the inorganic world--the difference
between them arising from the diverse combination and disposition of
identical forces, and not from any primary diversity, so far as we can
see.
I said just now that the Horse eventually died and became converted into
the same inorganic substances from whence all but an inappreciable
fraction of its substance demonstrably originated, so that the actual
wanderings of matter are as remarkable as the transmigrations of the
soul fabled by Indian tradition. But before death has occurred, in the
one sex or the other, and in fact in both, certain products or parts of
the organism have been set free, certain parts of the organisms of the
two sexes have come into contact with one another, and from that
conjunction, from that union which then takes place, there results the
formation of a new being. At stated times the mare, from a particular
part of the interior of her body, called the ovary, gets rid of a minute
particle of matter comparable in all essential respects with that which
we called a cell a little while since, which cell contains a kind of
nucleus in its centre, surrounded by a clear space and by a viscid mass
of protein substance (Fig. 33); and though it is different in appearance
from the eggs which we are mostly acquainted with, it is really an egg.
After a time this minute particle of matter, which may only be a small
fraction of a grain in weight, undergoes a series of changes,--wonderful,
complex changes. Finally, upon its surface there is fashioned a little
elevation, which afterwards becomes divided and marked by a groove. The
lateral boundaries of the groove extend upwards and downwards, and at
length give rise to a double tube. In the upper and smaller tube the
spinal marrow and brain are fashioned; in the lower, the alimentary
canal and heart; and at length two pairs of buds shoot out at the sides
of the body, and they are the rudiments of the limbs. In fact a true
drawing of a section of the embryo in this state would in all essential
respects resemble that diagram of a horse reduced to its simplest
expression, which I first placed before you (Fig. 32).
Slowly and gradually these changes take place. The whole of the body, at
first, can be broken up into "cells," which become in one place
metamorphosed into muscle,--in another place into gristle and bone,--in
another place into fibrous tissue,--and in another into hair; every part
becoming gradually and slowly fashioned, as if there were an artificer
at work in each of these complex structures that I have mentioned. This
embryo, as it is called, then passes into other conditions. I should
tell you that there is a time when the embryos of neither dog, nor
horse, nor porpoise, nor monkey, nor man, can be distinguished by any
essential feature one from the other; there is a time when they each and
all of them resemble this one of the Dog. But as development advances,
all the parts acquire their speciality, till at length you have the
embryo converted into the form of the parent from which it started. So
that, you see, this living animal, this horse, begins its existence as a
minute particle of nitrogenous matter, which, being supplied with
nutriment (derived, as I have shown, from the inorganic world), grows up
according to the special type and construction of its parents, works and
undergoes a constant waste, and that waste is made good by nutriment
derived from the inorganic world; the waste given off in this way being
directly added to the inorganic world. Eventually the animal itself
dies, and, by the process of decomposition, its whole body is returned
to those conditions of inorganic matter in which its substance
originated.
This, then, is that which is true of every living form, from the lowest
plant to the highest animal--to man himself. You might define the life
of every one in exactly the same terms as those which I have now used;
the difference between the highest and the lowest being simply in the
complexity of the developmental changes, the variety of the structural
forms, and the diversity of the physiological functions which are
exerted by each.
If I were to take an oak tree, as a specimen of the plant world, I
should find that it originated in an acorn, which, too, commenced in a
cell; the acorn is placed in the ground, and it very speedily begins to
absorb the inorganic matters I have named, adds enormously to its bulk,
and we can see it, year after year, extending itself upward and
downward, attracting and appropriating to itself inorganic materials,
which it vivifies, and eventually, as it ripens, gives off its own
proper acorns, which again run the same course. But I need not multiply
examples,--from the highest to the lowest the essential features of life
are the same, as I have described in each of these cases.
So much, then, for these particular features of the organic world, which
you can understand and comprehend, so long as you confine yourself to
one sort of living being, and study that only.
But, as you know, horses are not the only living creatures in the
world; and again, horses, like all other animals, have certain
limits--are confined to a certain area on the surface of the earth on
which we live,--and, as that is the simpler matter, I may take that
first. In its wild state, and before the discovery of America, when the
natural state of things was interfered with by the Spaniards, the Horse
was only to be found in parts of the earth which are known to
geographers as the Old World; that is to say, you might meet with horses
in Europe, Asia, or Africa; but there were none in Australia, and there
were none whatsoever in the whole continent of America, from Labrador
down to Cape Horn. This is an empirical fact, and it is what is called,
stated in the way I have given it you, the "Geographical Distribution"
of the Horse.
Why horses should be found in Europe, Asia, and Africa, and not in
America, is not obvious; the explanation that the conditions of life in
America are unfavourable to their existence, and that, therefore, they
had not been created there, evidently does not apply; for when the
invading Spaniards, or our own yeomen farmers, conveyed horses to these
countries for their own use, they were found to thrive well and multiply
very rapidly; and many are even now running wild in those countries, and
in a perfectly natural condition. Now, suppose we were to do for every
animal what we have here done for the Horse,--that is, to mark off and
distinguish the particular district or region to which each belonged;
and supposing we tabulated all these results, that would be called the
Geographical Distribution of animals, while a corresponding study of
plants would yield as a result the Geographical Distribution of plants.
I pass on from that now, as I merely wished to explain to you what I
meant by the use of the term "Geographical Distribution." As I said,
there is another aspect, and a much more important one, and that is, the
relations of the various animals to one another. The Horse is a very
well-defined matter-of-fact sort of animal, and we are all pretty
familiar with its structure. I dare say it may have struck you, that it
resembles very much no other member of the animal kingdom, except
perhaps the Zebra or the Ass. But let me ask you to look along these
diagrams. Here is the skeleton of the Horse, and here the skeleton of
the Dog. You will notice that we have in the Horse a skull, a backbone
and ribs, shoulder-blades and haunch-bones. In the fore-limb, one upper
arm-bone, two fore arm-bones, wrist-bones (wrongly called knee), and
middle hand-bones, ending in the three bones of a finger, the last of
which is sheathed in the horny hoof of the fore-foot: in the hind-limb,
one thigh-bone, two leg-bones, ankle-bones, and middle foot-bones,
ending in the three bones of a toe, the last of which is encased in the
hoof of the hind-foot. Now turn to the Dog's skeleton. We find
identically the same bones, but more of them, there being more toes in
each foot, and hence more toe-bones.
Well, that is a very curious thing! The fact is that the Dog and the
Horse--when one gets a look at them without the outward impediments of
the skin--are found to be made in very much the same sort of fashion.
And if I were to make a transverse section of the Dog, I should find the
same organs that I have already shown you as forming parts of the Horse.
Well, here is another skeleton--that of a kind of Lemur--you see he has
just the same bones; and if I were to make a transverse section of it,
it would be just the same again. In your mind's eye turn him round, so
as to put his backbone in a position inclined obliquely upwards and
forwards, just as in the next three diagrams, which represent the
skeletons of an Orang, a Chimpanzee, and a Gorilla, and you find you
have no trouble in identifying the bones throughout; and lastly turn to
the end of the series, the diagram representing a man's skeleton, and
still you find no great structural feature essentially altered. There
are the same bones in the same relations. From the Horse we pass on and
on, with gradual steps, until we arrive at last at the highest known
forms. On the other hand, take the other line of diagrams, and pass from
the Horse downwards in the scale to this fish; and still, though the
modifications are vastly greater, the essential framework of the
organization remains unchanged. Here, for instance, is a Porpoise; here
is its strong backbone, with the cavity running through it, which
contains the spinal cord; here are the ribs, here the shoulder-blade;
here is the little short upper-arm bone, here are the two forearm
bones, the wrist-bone, and the finger-bones.
Strange, is it not, that the Porpoise should have in this queer-looking
affair--its flapper (as it is called), the same fundamental elements as
the fore-leg of the Horse or the Dog, or the Ape or Man; and here you
will notice a very curious thing,--the hinder limbs are absent. Now, let
us make another jump. Let us go to the Codfish: here you see is the
forearm, in this large pectoral fin--carrying your mind's eye onward
from the flapper of the Porpoise. And here you have the hinder limbs
restored in the shape of these ventral fins. If I were to make a
transverse section of this, I should find just the same organs that we
have before noticed. So that, you see, there comes out this strange
conclusion as the result of our investigations, that the Horse, when
examined and compared with other animals, is found by no means to stand
alone in nature; but that there are an enormous number of other
creatures which have backbones, ribs, and legs, and other parts arranged
in the same general manner, and in all their formation exhibiting the
same broad peculiarities.
I am sure that you cannot have followed me even in this extremely
elementary exposition of the structural relations of animals, without
seeing what I have been driving at all through, which is, to show you
that, step by step, naturalists have come to the idea of a unity of
plan, or conformity of construction, among animals which appeared at
first sight to be extremely dissimilar.
And here you have evidence of such a unity of plan among all the animals
which have backbones, and which we technically call _Vertebrata_. But
there are multitudes of other animals, such as crabs, lobsters, spiders,
and so on, which we term _Annulosa_. In these I could not point out to
you the parts that correspond with those of the Horse,--the backbone,
for instance,--as they are constructed upon a very different principle,
which is also common to all of them; that is to say, the Lobster, the
Spider, and the Centipede, have a common plan running through their
whole arrangement, in just the same way that the Horse, the Dog, and the
Porpoise assimilate to each other.
Yet other creatures--whelks, cuttlefishes, oysters, snails, and all
their tribe (_Mollusca_)--resemble one another in the same way, but
differ from both _Vertebrata_ and _Annulosa_; and the like is true of
the animals called _Coelenterata_ (Polypes) and _Protozoa_
(animalcules and sponges).
Now, by pursuing this sort of comparison, naturalists have arrived at
the conviction that there are,--some think five, and some seven,--but
certainly not more than the latter number--and perhaps it is simpler to
assume five--distinct plans or constructions in the whole of the animal
world; and that the hundreds of thousands of species of creatures on the
surface of the earth, are all reducible to those five, or, at most,
seven, plans of organization.
But can we go no further than that? When one has got so far, one is
tempted to go on a step and inquire whether we cannot go back yet
further and bring down the whole to modifications of one primordial
unit. The anatomist cannot do this; but if he call to his aid the study
of development, he can do it. For we shall find that, distinct as those
plans are, whether it be a porpoise or man, or lobster, or any of those
other kinds I have mentioned, every one begins its existence with one
and the same primitive form,--that of the egg, consisting, as we have
seen, of a nitrogenous substance, having a small particle or nucleus in
the centre of it. Furthermore, the earlier changes of each are
substantially the same. And it is in this that lies that true "unity of
organization" of the animal kingdom which has been guessed at and
fancied for many years; but which it has been left to the present time
to be demonstrated by the careful study of development. But is it
possible to go another step further still, and to show that in the same
way the whole of the organic world is reducible to one primitive
condition of form? Is there among the plants the same primitive form of
organization, and is that identical with that of the animal kingdom? The
reply to that question, too, is not uncertain or doubtful. It is now
proved that every plant begins its existence under the same form; that
is to say, in that of a cell--a particle of nitrogenous matter having
substantially the same conditions. So that if you trace back the oak to
its first germ, or a man, or a horse, or lobster, or oyster, or any
other animal you choose to name, you shall find each and all of these
commencing their existence in forms essentially similar to each other:
and, furthermore, that the first processes of growth, and many of the
subsequent modifications, are essentially the same in principle in
almost all.
In conclusion, let me, in a few words, recapitulate the positions which
I have laid down. And you must understand that I have not been talking
mere theory; I have been speaking of matters which are as plainly
demonstrable as the commonest propositions of Euclid--of facts that must
form the basis of all speculations and beliefs in Biological science. We
have gradually traced down all organic forms, or, in other words, we
have analyzed the present condition of animated nature, until we found
that each species took its origin in a form similar to that under which
all the others commenced their existence. We have found the whole of the
vast array of living forms with which we are surrounded, constantly
growing, increasing, decaying, and disappearing; the animal constantly
attracting, modifying, and applying to its sustenance the matter of the
vegetable kingdom, which derived its support from the absorption and
conversion of inorganic matter. And so constant and universal is this
absorption, waste, and reproduction, that it may be said with perfect
certainty that there is left in no one of our bodies at the present
moment a millionth part of the matter of which they were originally
formed! We have seen, again, that not only is the living matter derived
from the inorganic world, but that the forces of that matter are all of
them correlative with and convertible into those of inorganic nature.
This, for our present purposes, is the best view of the present
condition of organic nature which I can lay before you: it gives you the
great outlines of a vast picture, which you must fill up by your own
study.
In the next lecture I shall endeavour in the same way to go back into
the past, and to sketch in the same broad manner the history of life in
epochs preceding our own.
V
THE PAST CONDITION OF ORGANIC
NATURE.
In the lecture which I delivered last Monday evening, I endeavoured to
sketch in a very brief manner, but as well as the time at my disposal
would permit, the present condition of organic nature, meaning by that
large title simply an indication of the great, broad, and general
principles which are to be discovered by those who look attentively at
the phenomena of organic nature as at present displayed. The general
result of our investigations might be summed up thus: we found that the
multiplicity of the forms of animal life, great as that may be, may be
reduced to a comparatively few primitive plans or types of construction;
that a further study of the development of those different forms
revealed to us that they were again reducible, until we at last brought
the infinite diversity of animal, and even vegetable life, down to the
primordial form of a single cell.
We found that our analysis of the organic world, whether animals or
plants, showed, in the long run, that they might both be reduced into,
and were, in fact, composed of the same constituents. And we saw that
the plant obtained the materials constituting its substance by a
peculiar combination of matters belonging entirely to the inorganic
world; that, then, the animal was constantly appropriating the
nitrogenous matters of the plant to its own nourishment, and returning
them back to the inorganic world, in what we spoke of as its waste; and
that, finally, when the animal ceased to exist, the constituents of its
body were dissolved and transmitted to that inorganic world whence they
had been at first abstracted. Thus we saw in both the blade of grass
and the horse but the same elements differently combined and arranged.
We discovered a continual circulation going on,--the plant drawing in
the elements of inorganic nature and combining them into food for the
animal creation; the animal borrowing from the plant the matter for its
own support, giving off during its life products which returned
immediately to the inorganic world; and that, eventually, the
constituent materials of the whole structure of both animals and plants
were thus returned to their original source: there was a constant
passage from one state of existence to another, and a returning back
again.
Lastly, when we endeavoured to form some notion of the nature of the
forces exercised by living beings, we discovered that they--if not
capable of being subjected to the same minute analysis as the
constituents of those beings themselves--that they were correlative
with--that they were the equivalents of the forces of inorganic
nature--that they were, in the sense in which the term is now used,
convertible with them. That was our general result.
And now, leaving the Present, I must endeavour in the same manner to put
before you the facts that are to be discovered in the Past history of
the living world, in the past conditions of organic nature. We have,
to-night, to deal with the facts of that history--a history involving
periods of time before which our mere human records sink into utter
insignificance--a history the variety and physical magnitude of whose
events cannot even be foreshadowed by the history of human life and
human phenomena--a history of the most varied and complex character.
We must deal with the history, then, in the first place, as we should
deal with all other histories. The historical student knows that his
first business should be to inquire into the validity of his evidence,
and the nature of the record in which the evidence is contained, that he
may be able to form a proper estimate of the correctness of the
conclusions which have been drawn from that evidence. So, here, we must
pass, in the first place, to the consideration of a matter which may
seem foreign to the question under discussion. We must dwell upon the
nature of the records, and the credibility of the evidence they contain;
we must look to the completeness or incompleteness of those records
themselves, before we turn to that which they contain and reveal. The
question of the credibility of the history, happily for us, will not
require much consideration, for, in this history, unlike those of human
origin, there can be no cavilling, no differences as to the reality and
truth of the facts of which it is made up; the facts state themselves,
and are laid out clearly before us.
But, although one of the greatest difficulties of the historical student
is cleared out of our path, there are other difficulties--difficulties
in rightly interpreting the facts as they are presented to us--which may
be compared with the greatest difficulties of any other kinds of
historical study.
What is this record of the past history of the globe, and what are the
questions which are involved in an inquiry into its completeness or
incompleteness? That record is composed of mud; and the question which
we have to investigate this evening resolves itself into a question of
the formation of mud. You may think, perhaps, that this is a vast
step--of almost from the sublime to the ridiculous--from the
contemplation of the history of the past ages of the world's existence
to the consideration of the history of the formation of mud! But, in
nature, there is nothing mean and unworthy of attention; there is
nothing ridiculous or contemptible in any of her works; and this
inquiry, you will soon see, I hope, takes us to the very root and
foundations of our subject.
How, then, is mud formed? Always, with some trifling exception, which I
need not consider now--always, as the result of the action of water,
wearing down and disintegrating the surface of the earth and rocks with
which it comes in contact--pounding and grinding it down, and carrying
the particles away to places where they cease to be disturbed by this
mechanical action, and where they can subside and rest. For the ocean,
urged by winds, washes, as we know, a long extent of coast, and every
wave, loaded as it is with particles of sand and gravel as it breaks
upon the shore, does something towards the disintegrating process. And
thus, slowly but surely, the hardest rocks are gradually ground down to
a powdery substance; and the mud thus formed, coarser or finer, as the
case may be, is carried by the rush of the tides, or currents, till it
reaches the comparatively deeper parts of the ocean, in which it can
sink to the bottom, that is, to parts where there is a depth of about
fourteen or fifteen fathoms, a depth at which the water is, usually,
nearly motionless, and in which, of course, the finer particles of this
detritus, or mud as we call it, sinks to the bottom.
Or, again, if you take a river, rushing down from its mountain sources,
brawling over the stones and rocks that intersect its path, loosening,
removing, and carrying with it in its downward course the pebbles and
lighter matters from its banks, it crushes and pounds down the rocks and
earths in precisely the same way as the wearing action of the sea waves.
The matters forming the deposit are torn from the mountain-side and
whirled impetuously into the valley, more slowly over the plain, thence
into the estuary, and from the estuary they are swept into the sea. The
coarser and heavier fragments are obviously deposited first, that is, as
soon as the current begins to lose its force by becoming amalgamated
with the stiller depths of the ocean, but the finer and lighter
particles are carried further on, and eventually deposited in a deeper
and stiller portion of the ocean.
It clearly follows from this that mud gives us a chronology; for it is
evident that supposing this, which I now sketch, to be the sea bottom,
and supposing this to be a coast-line; from the washing action of the
sea upon the rock, wearing and grinding it down into a sediment of mud,
the mud will be carried down and, at length, deposited in the deeper
parts of this sea-bottom, where it will form a layer; and then, while
that first layer is hardening, other mud which is coming from the same
source will, of course, be carried to the same place; and, as it is
quite impossible for it to get beneath the layer already there, it
deposits itself above it, and forms another layer, and in that way you
gradually have layers of mud constantly forming and hardening one above
the other, and conveying a record of time.
It is a necessary result of the operation of the law of gravitation that
the uppermost layer shall be the youngest and the lowest the oldest, and
that the different beds shall be older at any particular point or spot
in exactly the ratio of their depth from the surface. So that if they
were upheaved afterwards, and you had a series of these different layers
of mud, converted into sandstone, or limestone, as the case might be,
you might be sure that the bottom layer was deposited first, and that
the upper layers were formed afterwards. Here, you see, is the first
step in the history--these layers of mud give us an idea of time.
The whole surface of the earth,--I speak broadly, and leave out minor
qualifications,--is made up of such layers of mud, so hard, the majority
of them, that we call them rock, whether limestone or sandstone, or
other varieties of rock. And, seeing that every part of the crust of the
earth is made up in this way, you might think that the determination of
the chronology, the fixing of the time which it has taken to form this
crust is a comparatively simple matter. Take a broad average, ascertain
how fast the mud is deposited upon the bottom of the sea, or in the
estuary of rivers; take it to be an inch, or two, or three inches a
year, or whatever you may roughly estimate it at; then take the total
thickness of the whole series of stratified rocks, which geologists
estimate at twelve or thirteen miles, or about seventy thousand feet,
make a sum in short division, divide the total thickness by that of the
quantity deposited in one year, and the result will, of course, give you
the number of years which the crust has taken to form.
Truly, that looks a very simple process! It would be so except for
certain difficulties, the very first of which is that of finding how
rapidly sediments are deposited; but the main difficulty--a difficulty
which renders any certain calculations of such a matter out of the
question--is this, the sea-bottom on which the deposit takes place is
continually shifting.
Instead of the surface of the earth being that stable, fixed thing that
it is popularly believed to be, being, in common parlance, the very
emblem of fixity itself, it is incessantly moving, and is, in fact, as
unstable as the surface of the sea, except that its undulations are
infinitely slower and enormously higher and deeper.
Now, what is the effect of this oscillation? Take the case to which I
have previously referred. The finer or coarser sediments that are
carried down by the current of the river will only be carried out a
certain distance, and eventually, as we have already seen, on reaching
the stiller part of the ocean, will be deposited at the bottom.
Let C _y_ (Fig. 35) be the sea-bottom, _y_ D the shore, _x y_ the
sea-level, then the coarser deposit will subside over the region B, the
finer over A, while beyond A there will be no deposit at all; and,
consequently, no record will be kept, simply because no deposit is going
on. Now, suppose that the whole land, C, D, which we have regarded as
stationary, goes down, as it does so, both A and B go further out from
the shore, which will be at _y_^1, _x_^1 _y_^1, being the new sea-level.
The consequence will be that the layer of mud (A), being now, for the
most part, further than the force of the current is strong enough to
convey even the finest _débris_, will, of course, receive no more
deposits, and having attained a certain thickness, will now grow no
thicker.
[Illustration: FIG. 35.]
We should be misled in taking the thickness of that layer, whenever it
may be exposed to our view, as a record of time in the manner in which
we are now regarding this subject, as it would give us only an
imperfect and partial record: it would seem to represent too short a
period of time.
Suppose, on the other hand, that the land (C D) had gone on rising
slowly and gradually--say an inch or two inches in the course of a
century,--what would be the practical effect of that movement? Why, that
the sediment A and B which has been already deposited, would eventually
be brought nearer to the shore-level, and again subjected to the wear
and tear of the sea; and directly the sea begins to act upon it, it
would of course soon cut up and carry it away, to a greater or less
extent, to be re-deposited further out.
Well, as there is, in all probability, not one single spot on the whole
surface of the earth, which has not been up and down in this way a great
many times, it follows that the thickness of the deposits formed at any
particular spot cannot be taken (even supposing we had at first obtained
correct data as to the rate at which they took place) as affording
reliable information as to the period of time occupied in its deposit.
So that you see it is absolutely necessary from these facts, seeing that
our record entirely consists of accumulations of mud, superimposed one
on the other; seeing in the next place that any particular spots on
which accumulations have occurred, have been constantly moving up and
down, and sometimes out of the reach of a deposit, and at other times
its own deposit broken up and carried away, it follows that our record
must be in the highest degree imperfect, and we have hardly a trace left
of thick deposits, or any definite knowledge of the area that they
occupied in a great many cases. And mark this! That supposing even that
the whole surface of the earth had been accessible to the
geologist,--that man had had access to every part of the earth, and had
made sections of the whole, and put them all together,--even then his
record must of necessity be imperfect.
But to how much has man really access? If you will look at this Map you
will see that it represents the proportion of the sea to the earth: this
coloured part indicates all the dry land, and this other portion is the
water. You will notice at once that the water covers three-fifths of the
whole surface of the globe, and has covered it in the same manner ever
since man has kept any record of his own observations, to say nothing of
the minute period during which he has cultivated geological inquiry. So
that three-fifths of the surface of the earth is shut out from us
because it is under the sea. Let us look at the other two-fifths, and
see what are the countries in which anything that may be termed
searching geological inquiry has been carried out: a good deal of
France, Germany, and Great Britain and Ireland, bits of Spain, of Italy,
and of Russia, have been examined, but of the whole great mass of
Africa, except parts of the southern extremity, we know next to nothing;
little bits of India, but of the greater part of the Asiatic continent
nothing; bits of the Northern American States and of Canada, but of the
greater part of the continent of North America, and in still larger
proportion, of South America, nothing!
Under these circumstances, it follows that even with reference to that
kind of imperfect information which we can possess, it is only of about
the ten-thousandth part of the accessible parts of the earth that has
been examined properly. Therefore, it is with justice that the most
thoughtful of those who are concerned in these inquiries insist
continually upon the imperfection of the geological record; for, I
repeat, it is absolutely necessary, from the nature of things, that that
record should be of the most fragmentary and imperfect character.
Unfortunately this circumstance has been constantly forgotten. Men of
science, like young colts in a fresh pasture, are apt to be exhilarated
on being turned into a new field of inquiry, to go off at a hand-gallop,
in total disregard of hedges and ditches, to lose sight of the real
limitation of their inquiries, and to forget the extreme imperfection of
what is really known. Geologists have imagined that they could tell us
what was going on at all parts of the earth's surface during a given
epoch; they have talked of this deposit being contemporaneous with that
deposit, until, from our little local histories of the changes at
limited spots of the earth's surface, they have constructed a universal
history of the globe as full of wonders and portents as any other story
of antiquity.
But what does this attempt to construct a universal history of the
globe imply? It implies that we shall not only have a precise knowledge
of the events which have occurred at any particular point, but that we
shall be able to say what events, at any one spot, took place at the
same time with those at other spots.
Let us see how far that is in the nature of things practicable. Suppose
that here I make a section of the Lake of Killarney, and here the
section of another lake--that of Loch Lomond in Scotland for instance.
The rivers that flow into them are constantly carrying down deposits of
mud, and beds, or strata, are being as constantly formed, one above the
other, at the bottom of those lakes. Now, there is not a shadow of doubt
that in these two lakes the lower beds are all older than the
upper--there is no doubt about that; but what does _this_ tell us about
the age of any given bed in Loch Lomond, as compared with that of any
given bed in the Lake of Killarney? It is, indeed, obvious that if any
two sets of deposits are separated and discontinuous, there is
absolutely no means whatever given you by the nature of the deposit of
saying whether one is much younger or older than the other; but you may
say, as many have said and think, that the case is very much altered if
the beds which we are comparing are continuous. Suppose two beds of mud
hardened into rock,--A and B are seen in section (Fig. 36.)
[Illustration: FIG. 36.]
Well, you say, it is admitted that the lowermost bed is always the
older. Very well; B, therefore, is older than A. No doubt, _as a whole_,
it is so; or if any parts of the two beds which are in the same vertical
line are compared, it is so. But suppose you take what seems a very
natural step further, and say that the part _a_ of the bed A is younger
than the part _b_ of the bed B. Is this sound reasoning? If you find any
record of changes taking place at _b_, did they occur before any events
which took place while _a_ was being deposited? It looks all very plain
sailing, indeed, to say that they did; and yet there is no proof of
anything of the kind. As the former Director of this Institution, Sir H.
De la Beche, long ago showed, this reasoning may involve an entire
fallacy. It is extremely possible that _a_ may have been deposited ages
before _b_. It is very easy to understand how that can be. To return to
Fig. 35; when A and B were deposited, they were _substantially_
contemporaneous; A being simply the finer deposit, and B the coarser of
the same detritus or waste of land. Now suppose that that sea-bottom
goes down (as shown in Fig. 35), so that the first deposit is carried no
farther than _a_, forming the bed A^1, and the coarse no farther than
_b_, forming the bed B^1, the result will be the formation of two
continuous beds, one of fine sediment (A A^1) over-lapping another of
coarse sediment (B B^1). Now suppose the whole sea-bottom is raised up,
and a section exposed about the point A^1; no doubt, _at this spot_, the
upper bed is younger than the lower. But we should obviously greatly err
if we concluded that the mass of the upper bed at A was younger than the
lower bed at B; for we have just seen that they are contemporaneous
deposits. Still more should we be in error if we supposed the upper bed
at A to be younger than the continuation of the lower bed at B^1; for A
was deposited long before B^1. In fine, if, instead of comparing
immediately adjacent parts of two beds, one of which lies upon another,
we compare distant parts, it is quite possible that the upper may be any
number of years older than the under, and the under any number of years
younger than the upper.
Now you must not suppose that I put this before you for the purpose of
raising a paradoxical difficulty; the fact is, that the great mass of
deposits have taken place in sea-bottoms which are gradually sinking,
and have been formed under the very conditions I am here supposing.
Do not run away with the notion that this subverts the principle I laid
down at first. The error lies in extending a principle which is
perfectly applicable to deposits in the same vertical line to deposits
which are not in that relation to one another.
It is in consequence of circumstances of this kind, and of others that I
might mention to you, that our conclusions on and interpretations of the
record are really and strictly only valid so long as we confine
ourselves to one vertical section. I do not mean to tell you that there
are no qualifying circumstances, so that, even in very considerable
areas, we may safely speak of conformably superimposed beds being older
or younger than others at many different points. But we can never be
quite sure in coming to that conclusion, and especially we cannot be
sure if there is any break in their continuity, or any very great
distance between the points to be compared.
Well now, so much for the record itself,--so much for its
imperfections,--so much for the conditions to be observed in
interpreting it, and its chronological indications, the moment we pass
beyond the limits of a vertical linear section.
Now let us pass from the record to that which it contains,--from the
book itself to the writing and the figures on its pages. This writing
and these figures consist of remains of animals and plants which, in the
great majority of cases, have lived and died in the very spot in which
we now find them, or at least in the immediate vicinity. You must all of
you be aware--and I referred to the fact in my last lecture--that there
are vast numbers of creatures living at the bottom of the sea. These
creatures, like all others, sooner or later die, and their shells and
hard parts lie at the bottom; and then the fine mud which is being
constantly brought down by rivers and the action of the wear and tear of
the sea, covers them over and protects them from any further change or
alteration; and, of course, as in process of time the mud becomes
hardened and solidified, the shells of these animals are preserved and
firmly embedded in the limestone or sandstone which is being thus
formed. You may see in the galleries of the Museum upstairs specimens of
limestones in which such fossil remains of existing animals are
embedded. There are some specimens in which turtles' eggs have been
embedded in calcareous sand, and before the sun had hatched the young
turtles, they became covered over with calcareous mud, and thus have
been preserved and fossilized.
Not only does this process of embedding and fossilization occur with
marine and other aquatic animals and plants, but it affects those land
animals and plants which are drifted away to sea, or become buried in
bogs or morasses; and the animals which have been trodden down by their
fellows and crushed in the mud at the river's bank, as the herd have
come to drink. In any of these cases, the organisms may be crushed or be
mutilated, before or after putrefaction, in such a manner that perhaps
only a part will be left in the form in which it reaches us. It is,
indeed, a most remarkable fact, that it is quite an exceptional case to
find a skeleton of any one of all the thousands of wild land animals
that we know are constantly being killed, or dying in the course of
nature: they are preyed on and devoured by other animals, or die in
places where their bodies are not afterwards protected by mud. There are
other animals existing in the sea, the shells of which form exceedingly
large deposits. You are probably aware that before the attempt was made
to lay the Atlantic telegraphic cable, the Government employed vessels
in making a series of very careful observations and soundings of the
bottom of the Atlantic; and although, as we must all regret, that up to
the present time that project has not succeeded, we have the
satisfaction of knowing that it yielded some most remarkable results to
science. The Atlantic Ocean had to be sounded right across, to depths of
several miles in some places, and the nature of its bottom was carefully
ascertained. Well, now, a space of about 1000 miles wide from east to
west, and I do not exactly know how many from north to south, but at any
rate 600 or 700 miles, was carefully examined, and it was found that
over the whole of that immense area an excessively fine chalky mud is
being deposited; and this deposit is entirely made up of animals whose
hard parts are deposited in this part of the ocean, and are doubtless
gradually acquiring solidity and becoming metamorphosed into a chalky
limestone. Thus, you see, it is quite possible in this way to preserve
unmistakable records of animal and vegetable life. Whenever the
sea-bottom, by some of those undulations of the earth's crust that I
have referred to, becomes upheaved, and sections or borings are made, or
pits are dug, then we become able to examine the contents and
constituents of these ancient sea-bottoms, and find out what manner of
animals lived at that period.
Now it is a very important consideration in its bearing on the
completeness of the record, to inquire how far the remains contained in
these fossiliferous limestones are able to convey anything like an
accurate or complete account of the animals which were in existence at
the time of its formation. Upon that point we can form a very clear
judgment, and one in which there is no possible room for any mistake.
There are of course a great number of animals--such as jelly-fishes, and
other animals--without any hard parts, of which we cannot reasonably
expect to find any traces whatever: there is nothing of them to
preserve. Within a very short time, you will have noticed, after they
are removed from the water, they dry up to a mere nothing; certainly
they are not of a nature to leave any very visible traces of their
existence on such bodies as chalk or mud. Then again, look at land
animals; it is, as I have said, a very uncommon thing to find a land
animal entire after death. Insects and other carnivorous animals very
speedily pull them to pieces, putrefaction takes place, and so, out of
the hundreds of thousands that are known to die every year, it is the
rarest thing in the world to see one embedded in such a way that its
remains would be preserved for a lengthened period. Not only is this the
case, but even when animal remains have been safely embedded, certain
natural agents may wholly destroy and remove them.
Almost all the hard parts of animals--the bones and so on--are composed
chiefly of phosphate of lime and carbonate of lime. Some years ago, I
had to make an inquiry into the nature of some very curious fossils sent
to me from the North of Scotland. Fossils are usually hard bony
structures that have become embedded in the way I have described, and
have gradually acquired the nature and solidity of the body with which
they are associated; but in this case I had a series of _holes_ in some
pieces of rock, and nothing else. Those holes, however, had a certain
definite shape about them, and when I got a skilful workman to make
castings of the interior of these holes, I found that they were the
impressions of the joints of a backbone and of the armour of a great
reptile, twelve or more feet long. This great beast had died and got
buried in the sand, the sand had gradually hardened over the bones, but
remained porous. Water had trickled through it, and that water being
probably charged with a superfluity of carbonic acid, had dissolved all
the phosphate and carbonate of lime, and the bones themselves had thus
decayed and entirely disappeared; but as the sandstone happened to have
consolidated by that time, the precise shape of the bones was retained.
If that sandstone had remained soft a little longer, we should have
known nothing whatsoever of the existence of the reptile whose bones it
had encased.
How certain it is that a vast number of animals which have existed at
one period on this earth have entirely perished, and left no trace
whatever of their forms, may be proved to you by other considerations.
There are large tracts of sandstone in various parts of the world, in
which nobody has yet found anything but footsteps. Not a bone of any
description, but an enormous number of traces of footsteps. There is no
question about them. There is a whole valley in Connecticut covered with
these footsteps, and not a single fragment of the animals which made
them have yet been found. Let me mention another case while upon that
matter, which is even more surprising than those to which I have yet
referred. There is a limestone formation near Oxford, at a place called
Stonesfield, which has yielded the remains of certain very interesting
mammalian animals, and up to this time, if I recollect rightly, there
have been found seven specimens of its lower jaws, and not a bit of
anything else, neither limb-bones nor skull, or any part whatever; not a
fragment of the whole system! Of course, it would be preposterous to
imagine that the beasts had nothing else but a lower jaw! The
probability is, as Dr. Buckland showed, as the result of his
observations on dead dogs in the river Thames, that the lower jaw, not
being secured by very firm ligaments to the bones of the head, and being
a weighty affair, would easily be knocked off, or might drop away from
the body as it floated in water in a state of decomposition. The jaw
would thus be deposited immediately, while the rest of the body would
float and drift away altogether, ultimately reaching the sea, and
perhaps becoming destroyed. The jaw becomes covered up and preserved in
the river silt, and thus it comes that we have such a curious
circumstance as that of the lower jaws in the Stonesfield slates. So
that, you see, faulty as these layers of stone in the earth's crust are,
defective as they necessarily are as a record, the account of
contemporaneous vital phenomena presented by them is, by the necessity
of the case, infinitely more defective and fragmentary.
It was necessary that I should put all this very strongly before you,
because, otherwise, you might have been led to think differently of the
completeness of our knowledge by the next facts I shall state to you.
The researches of the last three-quarters of a century have, in truth,
revealed a wonderful richness of organic life in those rocks. Certainly
not fewer than thirty or forty thousand different species of fossils
have been discovered. You have no more ground for doubting that these
creatures really lived and died at or near the places in which we find
them than you have for like scepticism about a shell on the sea-shore.
The evidence is as good in the one case as in the other.
Our next business is to look at the general character of these fossil
remains, and it is a subject which will be requisite to consider
carefully; and the first point for us is to examine how much the extinct
_Flora_ and _Fauna_ as a _whole_--disregarding altogether the
_succession_ of their constituents, of which I shall speak
afterwards--differ from the _Flora_ and _Fauna_ of the present day;--how
far they differ in what we _do_ know about them, leaving altogether out
of consideration speculations based on what we _do not_ know.
I strongly imagine that if it were not for the peculiar appearance that
fossilized animals have, that any of you might readily walk through a
museum which contains fossil remains mixed up with those of the present
forms of life, and I doubt very much whether your uninstructed eyes
would lead you to see any vast or wonderful difference between the two.
If you looked closely, you would notice, in the first place, a great
many things very like animals with which you are acquainted now: you
would see differences of shape and proportion, but on the whole a close
similarity.
I explained what I meant by ORDERS the other day, when I described the
animal kingdom as being divided into sub-kingdoms, classes, and orders.
If you divide the animal kingdom into orders, you will find that there
are above one hundred and twenty. The number may vary on one side or the
other, but this is a fair estimate. That is the sum total of the orders
of all the animals which we know now, and which have been known in past
times, and left remains behind.
Now, how many of those are absolutely extinct? That is to say, how many
of these orders of animals have lived at a former period of the world's
history, but have at present no representatives? That is the sense in
which I meant to use the word "extinct." I mean that those animals did
live on this earth at one time, but have left no one of their kind with
us at the present moment. So that estimating the number of extinct
animals is a sort of way of comparing the past creation as a whole with
the present as a whole. Among the mammalia and birds there are none
extinct; but when we come to the reptiles there is a most wonderful
thing: out of the eight orders, or thereabouts, which you can make among
reptiles, one-half are extinct. These diagrams of the plesiosaurus, the
ichthyosaurus, the pterodactyle, give you a notion of some of these
extinct reptiles. And here is a cast of the pterodactyle and bones of
the ichthyosaurus and the plesiosaurus, just as fresh as if it had been
recently dug up in a churchyard. Thus, in the reptile class, there are
no less than half of the orders which are absolutely extinct. If we turn
to the _Amphibia_, there was one extinct order, the Labyrinthodonts,
typified by the large salamander-like beast shown in this diagram.
No order of fishes is known to be extinct. Every fish that we find in
the strata--to which I have been referring--can be identified and placed
in one of the orders which exist at the present day. There is not known
to be a single ordinal form of insect extinct. There are only two orders
extinct among the _Crustacea_. There is not known to be an extinct order
of these creatures, the parasitic and other worms; but there are two,
not to say three, absolutely extinct orders of this class, the
_Echinodermata_; out of all the orders of the _Coelenterata_ and
_Protozoa_ only one, the Rugose Corals.
So that, you see, out of somewhere about 120 orders of animals, taking
them altogether, you will not, at the outside estimate, find above ten
or a dozen extinct. Summing up all the orders of animals which have left
remains behind them, you will not find above ten or a dozen which cannot
be arranged with those of the present day; that is to say, that the
difference does not amount to much more than ten per cent.: and the
proportion of extinct orders of plants is still smaller. I think that
that is a very astounding, a most astonishing fact: seeing the enormous
epochs of time which have elapsed during the constitution of the surface
of the earth as it at present exists; it is, indeed, a most astounding
thing that the proportion of extinct ordinal types should be so
exceedingly small.
But now, there is another point of view in which we must look at this
past creation. Suppose that we were to sink a vertical pit through the
floor beneath us, and that I could succeed in making a section right
through in the direction of New Zealand, I should find in each of the
different beds through which I passed the remains of animals which I
should find in that stratum and not in the others. First, I should come
upon beds of gravel or drift containing the bones of large animals, such
as the elephant, rhinoceros, and cave tiger. Rather curious things to
fall across in Piccadilly! If I should dig lower still, I should come
upon a bed of what we call the London clay, and in this, as you will see
in our galleries upstairs, are found remains of strange cattle, remains
of turtles, palms, and large tropical fruits; with shell-fish such as
you see the like of now only in tropical regions. If I went below that,
I should come upon the chalk, and there I should find something
altogether different, the remains of ichthyosauri and pterodactyles, and
ammonites, and so forth.
I do not know what Mr. Godwin Austin would say comes next, but probably
rocks containing more ammonites, and more ichthyosauri and plesiosauri,
with a vast number of other things; and under that I should meet with
yet older rocks, containing numbers of strange shells and fishes; and in
thus passing from the surface to the lowest depths of the earth's crust,
the forms of animal life and vegetable life which I should meet with in
the successive beds would, looking at them broadly, be the more
different the further that I went down. Or, in other words, inasmuch as
we started with the clear principle, that in a series of
naturally-disposed mud beds the lowest are the oldest, we should come to
this result, that the farther we go back in time the more difference
exists between the animal and vegetable life of an epoch and that which
now exists. That was the conclusion to which I wished to bring you at
the end of this Lecture.
VI
THE METHOD BY WHICH THE CAUSES OF
THE PRESENT AND PAST CONDITIONS
OF ORGANIC NATURE ARE TO BE DISCOVERED.--THE
ORIGINATION OF LIVING
BEINGS.
In the two preceding lectures I have endeavoured to indicate to you the
extent of the subject-matter of the inquiry upon which we are engaged;
and having thus acquired some conception of the Past and Present
phenomena of Organic Nature, I must now turn to that which constitutes
the great problem which we have set before ourselves;--I mean, the
question of what knowledge we have of the causes of these phenomena of
organic nature, and how such knowledge is obtainable.
Here, on the threshold of the inquiry, an objection meets us. There are
in the world a number of extremely worthy, well-meaning persons, whose
judgments and opinions are entitled to the utmost respect on account of
their sincerity, who are of opinion that Vital Phenomena, and especially
all questions relating to the origin of vital phenomena, are questions
quite apart from the ordinary run of inquiry, and are, by their very
nature, placed out of our reach. They say that all these phenomena
originated miraculously, or in some way totally different from the
ordinary course of nature, and that therefore they conceive it to be
futile, not to say presumptuous, to attempt to inquire into them.
To such sincere and earnest persons, I would only say, that a question
of this kind is not to be shelved upon theoretical or speculative
grounds. You may remember the story of the Sophist who demonstrated to
Diogenes in the most complete and satisfactory manner that he could not
walk; that, in fact, all motion was an impossibility; and that Diogenes
refuted him by simply getting up and walking round his tub. So, in the
same way, the man of science replies to objections of this kind, by
simply getting up and walking onward, and showing what science has done
and is doing,--by pointing to that immense mass of facts which have been
ascertained and systematized under the forms of the great doctrines of
Morphology, of Development, of Distribution, and the like. He sees an
enormous mass of facts and laws relating to organic beings, which stand
on the same good sound foundation as every other natural law. With this
mass of facts and laws before us, therefore, seeing that, as far as
organic matters have hitherto been accessible and studied, they have
shown themselves capable of yielding to scientific investigation, we may
accept this as proof that order and law reign there as well as in the
rest of nature. The man of science says nothing to objectors of this
sort, but supposes that we can and shall walk to a knowledge of the
origin of organic nature, in the same way that we have walked to a
knowledge of the laws and principles of the inorganic world.
But there are objectors who say the same from ignorance and ill-will. To
such I would reply that the objection comes ill from them, and that the
real presumption, I may almost say the real blasphemy, in this matter,
is in the attempt to limit that inquiry into the causes of phenomena,
which is the source of all human blessings, and from which has sprung
all human prosperity and progress; for, after all, we can accomplish
comparatively little; the limited range of our own faculties bounds us
on every side,--the field of our powers of observation is small enough,
and he who endeavours to narrow the sphere of our inquiries is only
pursuing a course that is likely to produce the greatest harm to his
fellow-men.
But now, assuming, as we all do, I hope, that these phenomena are
properly accessible to inquiry, and setting out upon our search into the
causes of the phenomena of organic nature, or, at any rate, setting out
to discover how much we at present know upon these abstruse matters,
the question arises as to what is to be our course of proceeding, and
what method we must lay down for our guidance. I reply to that question,
that our method must be exactly the same as that which is pursued in any
other scientific inquiry, the method of scientific investigation being
the same for all orders of facts and phenomena whatsoever.
I must dwell a little on this point, for I wish you to leave this room
with a very clear conviction that scientific investigation is not, as
many people seem to suppose, some kind of modern black art. I say that
you might easily gather this impression from the manner in which many
persons speak of scientific inquiry, or talk about, inductive and
deductive philosophy, or the principles of the "Baconian philosophy." I
do protest that, of the vast number of cants in this world, there are
none, to my mind, so contemptible as the pseudo-scientific cant which is
talked about the "Baconian philosophy."
To hear people talk about the great Chancellor,--and a very great man he
certainly was,--you would think that it was he who had invented science,
and that there was no such thing as sound reasoning before the time of
Queen Elizabeth! Of course you say, that cannot possibly be true; you
perceive, on a moment's reflection, that such an idea is absurdly wrong;
and yet, so firmly rooted is this sort of impression,--I cannot call it
an idea, or conception,--the thing is too absurd to be entertained,--but
so completely does it exist at the bottom of most men's minds, that this
has been a matter of observation with me for many years past. There are
many men who, though knowing absolutely nothing of the subject with
which they may be dealing, wish, nevertheless, to damage the author of
some view with which they think fit to disagree. What they do, then, is
not to go and learn something about the subject, which one would
naturally think the best way of fairly dealing with it; but they abuse
the originator of the view they question, in a general manner, and wind
up by saying that, "After all, you know, the principles and method of
this author are totally opposed to the canons of the Baconian
philosophy." Then everybody applauds, as a matter of course, and agrees
that it must be so. But if you were to stop them all in the middle of
their applause, you would probably find that neither the speaker nor his
applauders could tell you how or in what way it was so; neither the one
nor the other having the slightest idea of what they mean when they
speak of the "Baconian philosophy."
You will understand, I hope, that I have not the slightest desire to
join in the outcry against either the morals, the intellect, or the
great genius of Lord Chancellor Bacon. He was undoubtedly a very great
man, let people say what they will of him; but notwithstanding all that
he did for philosophy, it would be entirely wrong to suppose that the
methods of modern scientific inquiry originated with him, or with his
age; they originated with the first man, whoever he was; and indeed
existed long before him, for many of the essential processes of
reasoning are exerted by the higher order of brutes as completely and
effectively as by ourselves. We see in many of the brute creation the
exercise of one, at least, of the same powers of reasoning as that which
we ourselves employ.
The method of scientific investigation is nothing but the expression of
the necessary mode of working of the human mind. It is simply the mode
at which all phenomena are reasoned about, rendered precise and exact.
There is no more difference, but there is just the same kind of
difference, between the mental operations of a man of science and those
of an ordinary person, as there is between the operations and methods of
a baker or of a butcher weighing out his goods in common scales, and the
operations of a chemist in performing a difficult and complex analysis
by means of his balance and finely-graduated weights. It is not that the
action of the scales in the one case, and the balance in the other,
differ in the principles of their construction or manner of working; but
the beam of one is set on an infinitely finer axis than the other, and
of course turns by the addition of a much smaller weight.
You will understand this better, perhaps, if I give you some familiar
example. You have all heard it repeated, I dare say, that men of science
work by means of Induction and Deduction, and that by the help of these
operations, they, in a sort of sense, wring from Nature certain other
things, which are called Natural Laws, and Causes, and that out of
these, by some cunning skill of their own, they build up Hypotheses and
Theories. And it is imagined by many, that the operations of the common
mind can be by no means compared with these processes, and that they
have to be acquired by a sort of special apprenticeship to the craft. To
hear all these large words, you would think that the mind of a man of
science must be constituted differently from that of his fellow-men; but
if you will not be frightened by terms, you will discover that you are
quite wrong, and that all these terrible apparatus are being used by
yourselves every day and every hour of your lives.
There is a well-known incident in one of Molière's plays, where the
author makes the hero express unbounded delight on being told that he
had been talking prose during the whole of his life. In the same way, I
trust, that you will take comfort, and be delighted with yourselves, on
the discovery that you have been acting on the principles of inductive
and deductive philosophy during the same period. Probably there is not
one here who has not in the course of the day had occasion to set in
motion a complex train of reasoning, of the very same kind, though
differing of course in degree, as that which a scientific man goes
through in tracing the causes of natural phenomena.
A very trivial circumstance will serve to exemplify this. Suppose you go
into a fruiterer's shop, wanting an apple,--you take up one, and, on
biting it, you find it is sour; you look at it, and see that it is hard
and green. You take up another one, and that too is hard, green, and
sour. The shopman offers you a third; but, before biting it, you examine
it, and find that it is hard and green, and you immediately say that you
will not have it, as it must be sour, like those that you have already
tried.
Nothing can be more simple than that, you think; but if you will take
the trouble to analyze and trace out into its logical elements what has
been done by the mind, you will be greatly surprised. In the first
place, you have performed the operation of Induction. You found that,
in two experiences, hardness and greenness in apples went together with
sourness. It was so in the first case, and it was confirmed by the
second. True, it is a very small basis, but still it is enough to make
an induction from; you generalize the facts, and you expect to find
sourness in apples where you get hardness and greenness. You found upon
that a general law, that all hard and green apples are sour; and that,
so far as it goes, is a perfect induction. Well, having got your natural
law in this way, when you are offered another apple which you find is
hard and green, you say, "All hard and green apples are sour; this apple
is hard and green, therefore this apple is sour." That train of
reasoning is what logicians call a syllogism, and has all its various
parts and terms,--its major premiss, its minor premiss, and its
conclusion. And, by the help of further reasoning, which, if drawn out,
would have to be exhibited in two or three other syllogisms, you arrive
at your final determination, "I will not have that apple." So that, you
see, you have, in the first place, established a law by Induction, and
upon that you have founded a Deduction, and reasoned out the special
conclusion of the particular case. Well now, suppose, having got your
law, that at some time afterwards, you are discussing the qualities of
apples with a friend: you will say to him, "It is a very curious
thing,--but I find that all hard and green apples are sour!" Your friend
says to you, "But how do you know that?" You at once reply, "Oh, because
I have tried them over and over again, and have always found them to be
so." Well, if we were talking science instead of common sense, we should
call that an Experimental Verification. And, if still opposed, you go
further, and say, "I have heard from the people in Somersetshire and
Devonshire, where a large number of apples are grown, that they have
observed the same thing. It is also found to be the case in Normandy,
and in North America. In short, I find it to be the universal experience
of mankind wherever attention has been directed to the subject."
Whereupon, your friend, unless he is a very unreasonable man, agrees
with you, and is convinced that you are quite right in the conclusion
you have drawn. He believes, although perhaps he does not know he
believes it, that the more extensive Verifications are,--that the more
frequently experiments have been made, and results of the same kind
arrived at,--that the more varied the conditions under which the same
results are attained, the more certain is the ultimate conclusion, and
he disputes the question no further. He sees that the experiment has
been tried under all sorts of conditions, as to time, place, and people,
with the same result; and he says with you, therefore, that the law you
have laid down must be a good one, and he must believe it.
In science we do the same thing;--the philosopher exercises precisely
the same faculties, though in a much more delicate manner. In scientific
inquiry it becomes a matter of duty to expose a supposed law to every
possible kind of verification, and to take care, moreover, that this is
done intentionally, and not left to a mere accident, as in the case of
the apples. And in science, as in common life, our confidence in a law
is in exact proportion to the absence of variation in the result of our
experimental verifications. For instance, if you let go your grasp of an
article you may have in your hand, it will immediately fall to the
ground. That is a very common verification of one of the best
established laws of nature--that of gravitation. The method by which men
of science establish the existence of that law is exactly the same as
that by which we have established the trivial proposition about the
sourness of hard and green apples. But we believe it in such an
extensive, thorough, and unhesitating manner because the universal
experience of mankind verifies it, and we can verify it ourselves at any
time; and that is the strongest possible foundation on which any natural
law can rest.
So much, then, by way of proof that the method of establishing laws in
science is exactly the same as that pursued in common life. Let us now
turn to another matter, (though really it is but another phase of the
same question,) and that is, the method by which, from the relations of
certain phenomena, we prove that some stand in the position of causes
towards the others.
I want to put the case clearly before you, and I will therefore show you
what I mean by another familiar example. I will suppose that one of you,
on coming down in the morning to the parlour of your house, finds that a
tea-pot and some spoons which had been left in the room on the previous
evening are gone,--the window is open, and you observe the mark of a
dirty hand on the window-frame, and perhaps, in addition to that, you
notice the impress of a hob-nailed shoe on the gravel outside. All these
phenomena have struck your attention instantly, and before two seconds
have passed you say, "Oh, somebody has broken open the window, entered
the room, and run off with the spoons and the tea-pot!" That speech is
out of your mouth in a moment. And you will probably add, "I know there
has; I am quite sure of it!" You mean to say exactly what you know; but
in reality you are giving expression to what is, in all essential
particulars, an Hypothesis. You do not _know_ it at all; it is nothing
but an hypothesis rapidly framed in your own mind! And, it is an
hypothesis founded on a long train of inductions and deductions.
What are those inductions and deductions, and how have you got at this
hypothesis? You have observed, in the first place, that the window is
open; but by a train of reasoning involving many Inductions and
Deductions, you have probably arrived long before at the General
Law--and a very good one it is--that windows do not open of themselves;
and you therefore conclude that something has opened the window. A
second general law that you have arrived at in the same way is, that
tea-pots and spoons do not go out of a window spontaneously, and you are
satisfied that, as they are not now where you left them, they have been
removed. In the third place, you look at the marks on the window-sill,
and the shoe-marks outside, and you say that in all previous experience
the former kind of mark has never been produced by anything else but the
hand of a human being; and the same experience shows that no other
animal but man at present wears shoes with hob-nails in them such as
would produce the marks in the gravel. I do not know, even if we could
discover any of those "missing links" that are talked about, that they
would help us to any other conclusion! At any rate the law which states
our present experience is strong enough for my present purpose. You next
reach the conclusion, that as these kinds of marks have not been left by
any other animals than men, or are liable to be formed in any other way
than by a man's hand and shoe, the marks in question have been formed by
a man in that way. You have, further, a general law, founded on
observation and experience, and that, too, is, I am sorry to say, a very
universal and unimpeachable one,--that some men are thieves; and you
assume at once from all these premisses--and that is what constitutes
your hypothesis--that the man who made the marks outside and on the
window-sill, opened the window, got into the room, and stole your
tea-pot and spoons. You have now arrived at a _Vera Causa_;--you have
assumed a Cause which it is plain is competent to produce all the
phenomena you have observed. You can explain all these phenomena only by
the hypothesis of a thief. But that is a hypothetical conclusion, of the
justice of which you have no absolute proof at all; it is only rendered
highly probable by a series of inductive and deductive reasonings.
I suppose your first action, assuming that you are a man of ordinary
common sense, and that you have established this hypothesis to your own
satisfaction, will very likely be to go off for the police, and set them
on the track of the burglar, with the view to the recovery of your
property. But just as you are starting with this object, some person
comes in, and on learning what you are about, says, "My good friend, you
are going on a great deal too fast. How do you know that the man who
really made the marks took the spoons? It might have been a monkey that
took them, and the man may have merely looked in afterwards." You would
probably reply, "Well, that is all very well, but you see it is contrary
to all experience of the way tea-pots and spoons are abstracted; so
that, at any rate, your hypothesis is less probable than mine." While
you are talking the thing over in this way, another friend arrives, one
of that good kind of people that I was talking of a little while ago.
And he might say, "Oh, my dear sir, you are certainly going on a great
deal too fast. You are most presumptuous. You admit that all these
occurrences took place when you were fast asleep, at a time when you
could not possibly have known anything about what was taking place. How
do you know that the laws of Nature are not suspended during the night?
It may be that there has been some kind of supernatural interference in
this case." In point of fact, he declares that your hypothesis is one of
which you cannot at all demonstrate the truth, and that you are by no
means sure that the laws of Nature are the same when you are asleep as
when you are awake.
Well, now, you cannot at the moment answer that kind of reasoning. You
feel that your worthy friend has you somewhat at a disadvantage. You
will feel perfectly convinced in your own mind, however, that you are
quite right, and you say to him, "My good friend, I can only be guided
by the natural probabilities of the case, and if you will be kind enough
to stand aside and permit me to pass, I will go and fetch the police."
Well, we will suppose that your journey is successful, and that by good
luck you meet with a policeman; that eventually the burglar is found
with your property on his person, and the marks correspond to his hand
and to his boots. Probably any jury would consider those facts a very
good experimental verification of your hypothesis, touching the cause of
the abnormal phenomena observed in your parlour, and would act
accordingly.
Now, in this supposititious case, I have taken phenomena of a very
common kind, in order that you might see what are the different steps in
an ordinary process of reasoning, if you will only take the trouble to
analyze it carefully. All the operations I have described, you will see,
are involved in the mind of any man of sense in leading him to a
conclusion as to the course he should take in order to make good a
robbery and punish the offender. I say that you are led, in that case,
to your conclusion by exactly the same train of reasoning as that which
a man of science pursues when he is endeavouring to discover the origin
and laws of the most occult phenomena. The process is, and always must
be, the same; and precisely the same mode of reasoning was employed by
Newton and Laplace in their endeavours to discover and define the causes
of the movements of the heavenly bodies, as you, with your own common
sense, would employ to detect a burglar. The only difference is, that
the nature of the inquiry being more abstruse, every step has to be most
carefully watched, so that there may not be a single crack or flaw in
your hypothesis. A flaw or crack in many of the hypotheses of daily life
may be of little or no moment as affecting the general correctness of
the conclusions at which we may arrive; but in a scientific inquiry a
fallacy, great or small, is always of importance, and is sure to be in
the long run constantly productive of mischievous, if not fatal results.
Do not allow yourselves to be misled by the common notion that an
hypothesis is untrustworthy simply because it is an hypothesis. It is
often urged, in respect to some scientific conclusion, that, after all,
it is only an hypothesis. But what more have we to guide us in
nine-tenths of the most important affairs of daily life than hypotheses,
and often very ill-based ones? So that in science, where the evidence of
an hypothesis is subjected to the most rigid examination, we may rightly
pursue the same course. You may have hypotheses and hypotheses. A man
may say, if he likes, that the moon is made of green cheese: that is an
hypothesis. But another man, who has devoted a great deal of time and
attention to the subject, and availed himself of the most powerful
telescopes and the results of the observations of others, declares that
in his opinion it is probably composed of materials very similar to
those of which our own earth is made up: and that is also only an
hypothesis. But I need not tell you that there is an enormous difference
in the value of the two hypotheses. That one which is based on sound
scientific knowledge is sure to have a corresponding value; and that
which is a mere hasty random guess is likely to have but little value.
Every great step in our progress in discovering causes has been made in
exactly the same way as that which I have detailed to you. A person
observing the occurrence of certain facts and phenomena asks, naturally
enough, what process, what kind of operation known to occur in nature
applied to the particular case, will unravel and explain the mystery?
Hence you have the scientific hypothesis; and its value will be
proportionate to the care and completeness with which its basis had been
tested and verified. It is in these matters as in the commonest affairs
of practical life: the guess of the fool will be folly, while the guess
of the wise man will contain wisdom. In all cases, you see that the
value of the result depends on the patience and faithfulness with which
the investigator applies to his hypothesis every possible kind of
verification.
I dare say I may have to return to this point by-and-by; but having
dealt thus far with our logical methods, I must now turn to something
which, perhaps, you may consider more interesting, or, at any rate, more
tangible. But in reality there are but few things that can be more
important for you to understand than the mental processes and the means
by which we obtain scientific conclusions and theories.[51] Having
granted that the inquiry is a proper one, and having determined on the
nature of the methods we are to pursue and which only can lead to
success, I must now turn to the consideration of our knowledge of the
nature of the processes which have resulted in the present condition of
organic nature.
Here, let me say at once, lest some of you misunderstand me, that I have
extremely little to report. The question of how the present condition of
organic nature came about, resolves itself into two questions. The first
is: How has organic or living matter commenced its existence? And the
second is: How has it been perpetuated? On the second question I shall
have more to say hereafter. But on the first one, what I now have to say
will be for the most part of a negative character.
If you consider what kind of evidence we can have upon this matter, it
will resolve itself into two kinds. We may have historical evidence and
we may have experimental evidence. It is, for example, conceivable,
that inasmuch as the hardened mud which forms a considerable portion of
the thickness of the earth's crust contains faithful records of the past
forms of life, and inasmuch as these differ more and more as we go
further down,--it is possible and conceivable that we might come to some
particular bed or stratum which should contain the remains of those
creatures with which organic life began upon the earth. And if we did
so, and if such forms of organic life were preservable, we should have
what I would call historical evidence of the mode in which organic life
began upon this planet. Many persons will tell you, and indeed you will
find it stated in many works on geology, that this has been done, and
that we really possess such a record; there are some who imagine that
the earliest forms of life of which we have as yet discovered any
record, are in truth the forms in which animal life began upon the
globe. The grounds on which they base that supposition are these:--That
if you go through the enormous thickness of the earth's crust and get
down to the older rocks, the higher vertebrate animals--the quadrupeds,
birds, and fishes--cease to be found; beneath them you find only the
invertebrate animals; and in the deepest and lowest rocks those remains
become scantier and scantier, not in any very gradual progression,
however, until, at length, in what are supposed to be the oldest rocks,
the animal remains which are found are almost always confined to four
forms,--_Oldhamia_, whose precise nature is not known, whether plant or
animal; _Lingula_, a kind of mollusc; _Trilobites_, a crustacean animal,
having the same essential plan of construction, though differing in many
details from a lobster or crab; and _Hymenocaris_, which is also a
crustacean. So that you have all the _Fauna_ reduced, at this period, to
four forms: one a kind of animal or plant that we know nothing about,
and three undoubted animals--two crustaceans and one mollusc.
I think, considering the organization of these mollusca and crustacea,
and looking at their very complex nature, that it does indeed require a
very strong imagination to conceive that these were the first created of
all living things. And you must take into consideration the fact that
we have not the slightest proof that these which we call the oldest beds
are really so: I repeat, we have not the slightest proof of it. When you
find in some places that in an enormous thickness of rocks there are but
very scanty traces of life, or absolutely none at all; and that in other
parts of the world rocks of the very same formation are crowded with the
records of living forms, I think it is impossible to place any reliance
on the supposition, or to feel oneself justified in supposing that these
are the forms in which life first commenced. I have not time here to
enter upon the technical grounds upon which I am led to this
conclusion,--that could hardly be done properly in half a dozen lectures
on that part alone;--I must content myself with saying that I do not at
all believe that these are the oldest forms of life.
I turn to the experimental side to see what evidence we have there. To
enable us to say that we know anything about the experimental
origination of organization and life, the investigator ought to be able
to take inorganic matters, such as carbonic acid, ammonia, water, and
salines, in any sort of inorganic combination, and be able to build them
up into Protein matter, and then that Protein matter ought to begin to
live in an organic form. That, nobody has done as yet, and I suspect it
will be a long while before anybody does do it. But the thing is by no
means so impossible as it looks; for the researches of modern chemistry
have shown us--I won't say the road towards it, but, if I may so say,
they have shown the finger-post pointing to the road that may lead to
it.
It is not many years ago--and you must recollect that Organic Chemistry
is a young science, not above a couple of generations old, you must not
expect too much of it,--it is not many years ago since it was said to be
perfectly impossible to fabricate any organic compound; that is to say,
any non-mineral compound which is to be found in an organized being. It
remained so for a very long period; but it is now a considerable number
of years since a distinguished foreign chemist contrived to fabricate
Urea, a substance of a very complex character, which forms one of the
waste products of animal structures. And of late years a number of other
compounds, such as Butyric Acid, and others, have been added to the
list. I need not tell you that chemistry is an enormous distance from
the goal I indicate; all I wish to point out to you is, that it is by no
means safe to say that that goal may not be reached one day. It may be
that it is impossible for us to produce the conditions requisite to the
origination of life; but we must speak modestly about the matter, and
recollect that Science has put her foot upon the bottom round of the
ladder. Truly he would be a bold man who would venture to predict where
she will be fifty years hence.
There is another inquiry which bears indirectly upon this question, and
upon which I must say a few words. You are all of you aware of the
phenomena of what is called spontaneous generation. Our forefathers,
down to the seventeenth century, or thereabouts, all imagined, in
perfectly good faith, that certain vegetable and animal forms gave
birth, in the process of their decomposition, to insect life. Thus, if
you put a piece of meat in the sun, and allowed it to putrefy, they
conceived that the grubs which soon began to appear were the result of
the action of a power of spontaneous generation which the meat
contained. And they could give you receipts for making various animal
and vegetable preparations which would produce particular kinds of
animals. A very distinguished Italian naturalist, named Redi, took up
the question, at a time when everybody believed in it; among others our
own great Harvey, the discoverer of the circulation of the blood. You
will constantly find his name quoted, however, as an opponent of the
doctrine of spontaneous generation; but the fact is, and you will see it
if you take the trouble to look into his works, Harvey believed it as
profoundly as any man of his time; but he happened to enunciate a very
curious proposition--that every living thing came from an _egg_; he did
not mean to use the word in the sense in which we now employ it, he only
meant to say that every living thing originated in a little rounded
particle of organized substance; and it is from this circumstance,
probably, that the notion of Harvey having opposed the doctrine
originated. Then came Redi, and he proceeded to upset the doctrine in a
very simple manner. He merely covered the piece of meat with some very
fine gauze, and then he exposed it to the same conditions. The result of
this was that no grubs or insects were produced; he proved that the
grubs originated from the insects who came and deposited their eggs in
the meat, and that they were hatched by the heat of the sun. By this
kind of inquiry he thoroughly upset the doctrine of spontaneous
generation, for his time at least.
Then came the discovery and application of the microscope to scientific
inquiries, which showed to naturalists that besides the organisms which
they already knew as living beings and plants, there were an immense
number of minute things which could be obtained apparently almost at
will from decaying vegetable and animal forms. Thus, if you took some
ordinary black pepper or some hay, and steeped it in water, you would
find in the course of a few days that the water had become impregnated
with an immense number of animalcules swimming about in all directions.
From facts of this kind naturalists were led to revive the theory of
spontaneous generation. They were headed here by an English
naturalist,--Needham,--and afterwards in France by the learned Buffon.
They said that these things were absolutely begotten in the water of the
decaying substances out of which the infusion was made. It did not
matter whether you took animal or vegetable matter, you had only to
steep it in water and expose it, and you would soon have plenty of
animalcules. They made an hypothesis about this which was a very fair
one. They said, this matter of the animal world, or of the higher
plants, appears to be dead, but in reality it has a sort of dim life
about it, which, if it is placed under fair conditions, will cause it to
break up into the forms of these little animalcules, and they will go
through their lives in the same way as the animal or plant of which they
once formed a part.
The question now became very hotly debated. Spallanzani, an Italian
naturalist, took up opposite views to those of Needham and Buffon, and
by means of certain experiments he showed that it was quite possible to
stop the process by boiling the water, and closing the vessel in which
it was contained. "Oh!" said his opponents, "but what do you know you
may be doing when you heat the air over the water in this way? You may
be destroying some property of the air requisite for the spontaneous
generation of the animalcules."
However, Spallanzani's views were supposed to be upon the right side,
and those of the others fell into discredit; although the fact was that
Spallanzani had not made good his views. Well, then, the subject
continued to be revived from time to time, and experiments were made by
several persons; but these experiments were not altogether satisfactory.
It was found that if you put an infusion in which animalcules would
appear if it were exposed to the air into a vessel and boiled it, and
then sealed up the mouth of the vessel, so that no air, save such as had
been heated to 212°, could reach its contents, that then no animalcules
would be found; but if you took the same vessel and exposed the infusion
to the air, then you would get animalcules. Furthermore, it was found
that if you connected the mouth of the vessel with a red-hot tube in
such a way that the air would have to pass through the tube before
reaching the infusion, that then you would get no animalcules. Yet
another thing was noticed: if you took two flasks containing the same
kind of infusion, and left one entirely exposed to the air, and in the
mouth of the other placed a ball of cotton wool, so that the air would
have to filter itself through it before reaching the infusion, that
then, although you might have plenty of animalcules in the first flask,
you would certainly obtain none from the second.
These experiments, you see, all tended towards one conclusion--that the
infusoria were developed from little minute spores or eggs which were
constantly floating in the atmosphere, and which lose their power of
germination if subjected to heat. But one observer now made another
experiment, which seemed to go entirely the other way, and puzzled him
altogether. He took some of this boiled infusion that I have been
speaking of, and by the use of a mercurial bath--a kind of trough used
in laboratories--he deftly inverted a vessel containing the infusion
into the mercury, so that the latter reached a little beyond the level
of the mouth of the _inverted_ vessel. You see that he thus had a
quantity of the infusion shut off from any possible communication with
the outer air by being inverted upon a bed of mercury.
He then prepared some pure oxygen and nitrogen gases, and passed them by
means of a tube going from the outside of the vessel, up through the
mercury into the infusion; so that he thus had it exposed to a perfectly
pure atmosphere of the same constituents as the external air. Of course,
he expected he would get no infusorial animalcules at all in that
infusion; but, to his great dismay and discomfiture, he found he almost
always did get them.
Furthermore, it has been found that experiments made in the manner
described above answer well with most infusions; but that if you fill
the vessel with boiled milk, and then stop the neck with cotton-wool,
you _will_ have infusoria. So that you see there were two experiments
that brought you to one kind of conclusion, and three to another; which
was a most unsatisfactory state of things to arrive at in a scientific
inquiry.
Some few years after this, the question began to be very hotly discussed
in France. There was M. Pouchet, a professor at Rouen, a very learned
man, but certainly not a very rigid experimentalist. He published a
number of experiments of his own, some of which were very ingenious, to
show that if you went to work in a proper way, there was a truth in the
doctrine of spontaneous generation. Well, it was one of the most
fortunate things in the world that M. Pouchet took up this question,
because it induced a distinguished French chemist, M. Pasteur, to take
up the question on the other side; and he has certainly worked it out in
the most perfect manner. I am glad to say, too, that he has published
his researches in time to enable me to give you an account of them. He
verified all the experiments which I have just mentioned to you--and
then finding those extraordinary anomalies, as in the case of the
mercury bath and the milk, he set himself to work to discover their
nature. In the case of milk he found it to be a question of temperature.
Milk in a fresh state is slightly alkaline; and it is a very curious
circumstance, but this very slight degree of alkalinity seems to have
the effect of preserving the organisms which fall into it from the air
from being destroyed at a temperature of 212°, which is the boiling
point. But if you raise the temperature 10° when you boil it, the milk
behaves like everything else; and if the air with which it comes in
contact, after being boiled at this temperature, is passed through a
red-hot tube, you will not get a trace of organisms.
He then turned his attention to the mercury bath, and found on
examination that the surface of the mercury was almost always covered
with a very fine dust. He found that even the mercury itself was
positively full of organic matters; that from being constantly exposed
to the air, it had collected an immense number of these infusorial
organisms from the air. Well, under these circumstances he felt that the
case was quite clear, and that the mercury was not what it had appeared
to M. Schwann to be,--a bar to the admission of these organisms; but
that, in reality, it acted as a reservoir from which the infusion was
immediately supplied with the large quantity that had so puzzled him.
But not content with explaining the experiments of others, M. Pasteur
went to work to satisfy himself completely. He said to himself: "If my
view is right, and if, in point of fact, all these appearances of
spontaneous generation are altogether due to the falling of minute germs
suspended in the atmosphere,--why, I ought not only to be able to show
the germs, but I ought to be able to catch and sow them, and produce the
resulting organisms." He, accordingly, constructed a very ingenious
apparatus to enable him to accomplish the trapping of the "_germ dust_"
in the air. He fixed in the window of his room a glass tube, in the
centre of which he had placed a ball of gun-cotton, which, as you all
know, is ordinary cotton-wool, which, from having been steeped in strong
acid, is converted into a substance of great explosive power. It is also
soluble in alcohol and ether. One end of the glass tube was, of course,
open to the external air; and at the other end of it he placed an
aspirator, a contrivance for causing a current of the external air to
pass through the tube. He kept this apparatus going for four-and-twenty
hours, and then removed the _dusted_ gun-cotton, and dissolved it in
alcohol and ether. He then allowed this to stand for a few hours, and
the result was, that a very fine dust was gradually deposited at the
bottom of it. That dust, on being transferred to the stage of a
microscope, was found to contain an enormous number of starch grains.
You know that the materials of our food and the greater portion of
plants are composed of starch, and we are constantly making use of it in
a variety of ways, so that there is always a quantity of it suspended in
the air. It is these starch grains which form many of those bright
specks that we see dancing in a ray of light sometimes. But besides
these, M. Pasteur found also an immense number of other organic
substances such as spores of fungi, which had been floating about in the
air and had got caged in this way.
He went farther, and said to himself, "If these really are the things
that give rise to the appearance of spontaneous generation, I ought to
be able to take a ball of this _dusted_ gun-cotton and put it into one
of my vessels, containing that boiled infusion which has been kept away
from the air, and in which no infusoria are at present developed, and
then, if I am right, the introduction of this gun-cotton will give rise
to organisms."
Accordingly, he took one of these vessels of infusion, which had been
kept eighteen months, without the least appearance of life in it, and by
a most ingenious contrivance, he managed to break it open and introduce
such a ball of gun-cotton, without allowing the infusion or the cotton
ball to come into contact with any air but that which had been subjected
to a red heat, and in twenty-four hours he had the satisfaction of
finding all the indications of what had been hitherto called spontaneous
generation. He had succeeded in catching the germs and developing
organisms in the way he had anticipated.
It now struck him that the truth of his conclusions might be
demonstrated without all the apparatus he had employed. To do this, he
took some decaying animal or vegetable substance, such as urine, which
is an extremely decomposable substance, or the juice of yeast, or
perhaps some other artificial preparation, and filled a vessel having a
long tubular neck, with it. He then boiled the liquid and bent that long
neck into an S shape or zig-zag, leaving it open at the end. The
infusion then gave no trace of any appearance of spontaneous generation,
however long it might be left, as all the germs in the air were
deposited in the beginning of the bent neck. He then cut the tube close
to the vessel, and allowed the ordinary air to have free and direct
access; and the result of that was the appearance of organisms in it, as
soon as the infusion had been allowed to stand long enough to allow of
the growth of those it received from the air, which was about
forty-eight hours. The result of M. Pasteur's experiments proved,
therefore, in the most conclusive manner, that all the appearances of
spontaneous generation arose from nothing more than the deposition of
the germs of organisms which were constantly floating in the air.
To this conclusion, however, the objection was made, that if that were
the cause, then the air would contain such an enormous number of these
germs, that it would be a continual fog. But M. Pasteur replied that
they are not there in anything like the number we might suppose, and
that an exaggerated view has been held on that subject; he showed that
the chances of animal or vegetable life appearing in infusions, depend
entirely on the conditions under which they are exposed. If they are
exposed to the ordinary atmosphere around us, why, of course, you may
have organisms appearing early. But, on the other hand, if they are
exposed to air at a great height, or in some very quiet cellar, you will
often not find a single trace of life.
So that M. Pasteur arrived at last at the clear and definite result,
that all these appearances are like the case of the worms in the piece
of meat, which was refuted by Redi, simply germs carried by the air and
deposited in the liquids in which they afterwards appear. For my own
part, I conceive that, with the particulars of M. Pasteur's experiments
before us, we cannot fail to arrive at his conclusions; and that the
doctrine of spontaneous generation has received a final _coup de grâce_.
You, of course, understand that all this in no way interferes with the
_possibility_ of the fabrication of organic matters by the direct method
to which I have referred, remote as that possibility may be.
FOOTNOTES:
[51] Those who wish to study fully the doctrines of which I have
endeavoured to give some rough and ready illustrations, must read Mr.
John Stuart Mill's "System of Logic."
VII
THE PERPETUATION OF LIVING BEINGS,
HEREDITARY TRANSMISSION AND
VARIATION.
The inquiry which we undertook, at our last meeting, into the state of
our knowledge of the causes of the phenomena of organic nature,--of the
past and of the present,--resolved itself into two subsidiary inquiries:
the first was, whether we know anything, either historically or
experimentally, of the mode of origin of living beings; the second
subsidiary inquiry was, whether, granting the origin, we know anything
about the perpetuation and modifications of the forms of organic beings.
The reply which I had to give to the first question was altogether
negative, and the chief result of my last lecture was, that, neither
historically nor experimentally, do we at present know anything
whatsoever about the origin of living forms. We saw that, historically,
we are not likely to know anything about it, although we may perhaps
learn something experimentally; but that at present we are an enormous
distance from the goal I indicated.
I now, then, take up the next question, What do we know of the
reproduction, the perpetuation, and the modifications of the forms of
living beings, supposing that we have put the question as to their
origination on one side, and have assumed that at present the causes of
their origination are beyond us, and that we know nothing about them?
Upon this question the state of our knowledge is extremely different; it
is exceedingly large: and, if not complete, our experience is certainly
most extensive. It would be impossible to lay it all before you, and the
most I can do, or need do to-night, is to take up the principal points
and put them before you with such prominence as may subserve the
purposes of our present argument.
The method of the perpetuation of organic beings is of two kinds,--the
asexual and the sexual. In the first the perpetuation takes place from
and by a particular act of an individual organism, which sometimes may
not be classed as belonging to any sex at all. In the second case, it is
in consequence of the mutual action and inter-action of certain portions
of the organisms of usually two distinct individuals--the male and the
female. The cases of asexual perpetuation are by no means so common as
the cases of sexual perpetuation; and they are by no means so common in
the animal as in the vegetable world. You are all probably familiar with
the fact, as a matter of experience, that you can propagate plants by
means of what are called "cuttings"; for example, that by taking a
cutting from a geranium plant, and rearing it properly, by supplying it
with light and warmth and nourishment from the earth, it grows up and
takes the form of its parent, having all the properties and
peculiarities of the original plant.
Sometimes this process, which the gardener performs artificially, takes
place naturally; that is to say, a little bulb, or portion of the plant,
detaches itself, drops off, and becomes capable of growing as a separate
thing. That is the case with many bulbous plants, which throw off in
this way secondary bulbs, which are lodged in the ground and become
developed into plants. This is an asexual process, and from it results
the repetition or reproduction of the form of the original being from
which the bulb proceeds.
Among animals the same thing takes place. Among the lower forms of
animal life, the infusorial animalculæ we have already spoken of throw
off certain portions, or break themselves up in various directions,
sometimes transversely or sometimes longitudinally; or they may give off
buds, which detach themselves and develop into their proper forms. There
is the common fresh-water Polype, for instance, which multiplies itself
in this way. Just in the same way as the gardener is able to multiply
and reproduce the peculiarities and characters of particular plants by
means of cuttings, so can the physiological experimentalist,--as was
shown by the Abbé Trembley many years ago,--so can he do the same thing
with many of the lower forms of animal life. M. de Trembley showed that
you could take a polype and cut it into two, or four, or many pieces,
mutilating it in all directions, and the pieces would still grow up and
reproduce completely the original form of the animal. These are all
cases of asexual multiplication, and there are other instances, and
still more extraordinary ones, in which this process takes place
naturally, in a more hidden, a more recondite kind of way. You are all
of you familiar with that little green insect, the _Aphis_ or blight, as
it is called. These little animals, during a very considerable part of
their existence, multiply themselves by means of a kind of internal
budding, the buds being developed into essentially asexual animals,
which are neither male nor female; they become converted into young
_Aphides_, which repeat the process, and their offspring after them, and
so on again; you may go on for nine or ten, or even twenty or more
successions; and there is no very good reason to say how soon it might
terminate, or how long it might not go on if the proper conditions of
warmth and nourishment were kept up.
Sexual reproduction is quite a distinct matter. Here, in all these
cases, what is required is the detachment of two portions of the
parental organisms, which portions we know as the egg or the
spermatozoon. In plants it is the ovule and the pollen-grain, as in the
flowering plants, or the ovule and the antherozooid, as in the
flowerless. Among all forms of animal life, the spermatozoa proceed from
the male sex, and the egg is the product of the female. Now, what is
remarkable about this mode of reproduction is this, that the egg by
itself, or the spermatozoa by themselves, are unable to assume the
parental form; but if they be brought into contact with one another, the
effect of the mixture of organic substances proceeding from two sources
appears to confer an altogether new vigour to the mixed product. This
process is brought about, as we all know, by the sexual intercourse of
the two sexes, and is called the act of impregnation. The result of
this act on the part of the male and female is, that the formation of a
new being is set up in the ovule or egg; this ovule or egg soon begins
to be divided and subdivided, and to be fashioned into various complex
organisms, and eventually to develop into the form of one of its
parents, as I explained in the first lecture. These are the processes by
which the perpetuation of organic beings is secured. Why there should be
the two modes--why this reinvigoration should be required on the part of
the female element we do not know; but it is most assuredly the fact,
and it is presumable, that, however long the process of asexual
multiplication could be continued,--I say there is good reason to
believe that it would come to an end if a new commencement were not
obtained by a conjunction of the two sexual elements.
That character which is common to these two distinct processes is this,
that, whether we consider the reproduction, or perpetuation, or
modification of organic beings as they take place asexually, or as they
may take place sexually,--in either case, I say, the offspring has a
constant tendency to assume, speaking generally, the character of the
parent. As I said just now, if you take a slip of a plant, and tend it
with care, it will eventually grow up and develop into a plant like that
from which it had sprung; and this tendency is so strong that, as
gardeners know, this mode of multiplying by means of cuttings is the
only secure mode of propagating very many varieties of plants; the
peculiarity of the primitive stock seems to be better preserved if you
propagate it by means of a slip than if you resort to the sexual mode.
Again, in experiments upon the lower animals, such as the polype, to
which I have referred, it is most extraordinary that, although cut up
into various pieces, each particular piece will grow up into the form of
the primitive stock; the head, if separated, will reproduce the body and
the tail; and if you cut off the tail, you will find that that will
reproduce the body and all the rest of the members, without in any way
deviating from the plan of the organism from which these portions have
been detached. And so far does this go, that some experimentalists have
carefully examined the lower orders of animals,--among them the Abbé
Spallanzani, who made a number of experiments upon snails and
salamanders,--and have found that they might mutilate them to an
incredible extent; that you might cut off the jaw or the greater part of
the head, or the leg or the tail, and repeat the experiment several
times, perhaps, cutting off the same member again and again; and yet
each of those types would be reproduced according to the primitive type:
nature making no mistake, never putting on a fresh kind of leg, or head,
or tail, but always tending to repeat and to return to the primitive
type.
It is the same in sexual reproduction: it is a matter of perfectly
common experience, that the tendency on the part of the offspring always
is, speaking broadly, to reproduce the form of the parents. The proverb
has it that the thistle does not bring forth grapes; so, among
ourselves, there is always a likeness, more or less marked and distinct,
between children and their parents. That is a matter of familiar and
ordinary observation. We notice the same thing occurring in the cases of
the domestic animals--dogs, for instance, and their offspring. In all
these cases of propagation and perpetuation, there seems to be a
tendency in the offspring to take the characters of the parental
organisms. To that tendency a special name is given--and as I may very
often use it, I will write it up here on this blackboard that you may
remember it--it is called _Atavism_; it expresses this tendency to
revert to the ancestral type, and comes from the Latin word _atavus_,
ancestor.
Well, this _Atavism_which I shall speak of, is, as I said before, one of
the most marked and striking tendencies of organic beings; but, side by
side with this hereditary tendency there is an equally distinct and
remarkable tendency to variation. The tendency to reproduce the original
stock has, as it were, its limits, and side by side with it there is a
tendency to vary in certain directions, as if there were two opposing
powers working upon the organic being, one tending to take it in a
straight line, and the other tending to make it diverge from that
straight line, first to one side and then to the other.
So that you see these two tendencies need not precisely contradict one
another, as the ultimate result may not always be very remote from what
would have been the case if the line had been quite straight.
This tendency to variation is less marked in that mode of propagation
which takes place asexually; it is in that mode that the minor
characters of animal and vegetable structures are most completely
preserved. Still, it will happen sometimes, that the gardener, when he
has planted a cutting of some favourite plant, will find, contrary to
his expectation, that the slip grows up a little different from the
primitive stock--that it produces flowers of a different colour or make,
or some deviation in one way or another. This is what is called the
"sporting" of plants.
In animals the phenomena of asexual propagation are so obscure, that at
present we cannot be said to know much about them; but if we turn to
that mode of perpetuation which results from the sexual process, then we
find variation a perfectly constant occurrence, to a certain extent;
and, indeed, I think that a certain amount of variation from the
primitive stock is the necessary result of the method of sexual
propagation itself; for, inasmuch as the thing propagated proceeds from
two organisms of different sexes and different makes and temperaments,
and as the offspring is to be either of one sex or the other, it is
quite clear that it cannot be an exact diagonal of the two, or it would
be of no sex at all; it cannot be an exact intermediate form between
that of each of its parents--it must deviate to one side or the other.
You do not find that the male follows the precise type of the male
parent, nor does the female always inherit the precise characteristics
of the mother,--there is always a proportion of the female character in
the male offspring, and of the male character in the female offspring.
That must be quite plain to all of you who have looked at all
attentively on your own children or those of your neighbours; you will
have noticed how very often it may happen that the son shall exhibit the
maternal type of character, or the daughter possess the characteristics
of the father's family. There are all sorts of intermixtures and
intermediate conditions between the two, where complexion, or beauty, or
fifty other different peculiarities belonging to either side of the
house, are reproduced in other members of the same family. Indeed, it is
sometimes to be remarked in this kind of variation, that the variety
belongs, strictly speaking, to neither of the immediate parents; you
will see a child in a family who is not like either its father or its
mother; but some old person who knew its grandfather or grandmother, or,
it may be, an uncle, or, perhaps, even a more distant relative, will see
a great similarity between the child and one of these. In this way it
constantly happens that the characteristic of some previous member of
the family comes out and is reproduced and recognized in the most
unexpected manner.
But apart from that matter of general experience, there are some cases
which put that curious mixture in a very clear light. You are aware that
the offspring of the Ass and the Horse, or rather of the he-Ass and the
Mare, is what is called a Mule; and, on the other hand, the offspring of
the Stallion and the she-Ass is what is called a _Hinny_. It is a very
rare thing in this country to see a Hinny. I never saw one myself; but
they have been very carefully studied. Now, the curious thing is this,
that although you have the same elements in the experiment in each case,
the offspring is entirely different in character, according as the male
influence comes from the Ass or the Horse. Where the Ass is the male, as
in the case of the Mule, you find that the head is like that of the Ass,
that the ears are long, the tail is tufted at the end, the feet are
small, and the voice is an unmistakable bray; these are all points of
similarity to the Ass; but, on the other hand, the barrel of the body
and the cut of the neck are much more like those of the Mare. Then, if
you look at the Hinny,--the result of the union of the Stallion and the
she-Ass, then you find it is the Horse that has the predominance; that
the head is more like that of the Horse, the ears are shorter, the legs
coarser, and the type is altogether altered; while the voice, instead of
being a bray, is the ordinary neigh of the Horse. Here, you see, is a
most curious thing: you take exactly the same elements, Ass and Horse,
but you combine the sexes in a different manner, and the result is
modified accordingly. You have in this case, however, a result which is
not general and universal--there is usually an important preponderance,
but not always on the same side.
Here, then, is one intelligible, and, perhaps, necessary cause of
variation: the fact, that there are two sexes sharing in the production
of the offspring, and that the share taken by each is different and
variable, not only for each combination, but also for different members
of the same family.
Secondly, there is a variation, to a certain extent,--though in all
probability the influence of this cause has been very much
exaggerated--but there is no doubt that variation is produced, to a
certain extent, by what are commonly known as external conditions,--such
as temperature, food, warmth, and moisture. In the long run, every
variation depends, in some sense, upon external conditions, seeing that
everything has a cause of its own. I use the term "external conditions"
now in the sense in which it is ordinarily employed: certain it is, that
external conditions have a definite effect. You may take a plant which
has single flowers, and by dealing with the soil, and nourishment, and
so on, you may by-and-by convert single flowers into double flowers, and
make thorns shoot out into branches. You may thicken or make various
modifications in the shape of the fruit. In animals, too, you may
produce analogous changes in this way, as in the case of that deep
bronze colour which persons rarely lose after having passed any length
of time in tropical countries. You may also alter the development of the
muscles very much, by dint of training; all the world knows that
exercise has a great effect in this way; we always expect to find the
arm of a blacksmith hard and wiry, and possessing a large development of
the brachial muscles. No doubt, training, which is one of the forms of
external conditions, converts what are originally only instructions,
teachings, into habits, or, in other words, into organizations, to a
great extent; but this second cause of variation cannot be considered to
be by any means a large one. The third cause that I have to mention,
however, is a very extensive one. It is one that, for want of a better
name, has been called "spontaneous variation"; which means that when we
do not know anything about the cause of phenomena, we call it
spontaneous. In the orderly chain of causes and effects in this world,
there are very few things of which it can be said with truth that they
are spontaneous. Certainly not in these physical matters,--in these
there is nothing of the kind,--everything depends on previous
conditions. But when we cannot trace the cause of phenomena, we call
them spontaneous.
Of these variations, multitudinous as they are, but little is known with
perfect accuracy, I will mention to you some two or three cases, because
they are very remarkable in themselves, and also because I shall want to
use them afterwards. Réaumur, a famous French naturalist, a great many
years ago, in an essay which he wrote upon the art of hatching
chickens,--which was indeed a very curious essay,--had occasion to speak
of variations and monstrosities. One very remarkable case had come under
his notice of a variation in the form of a human member, in the person
of a Maltese, of the name of Gratio Kelleia, who was born with six
fingers upon each hand, and the like number of toes to each of his feet.
That was a case of spontaneous variation. Nobody knows why he was born
with that number of fingers and toes, and as we don't know, we call it a
case of "spontaneous" variation. There is another remarkable case also.
I select these, because they happen to have been observed and noted very
carefully at the time. It frequently happens that a variation occurs,
but the persons who notice it do not take any care in noting down the
particulars, until at length, when inquiries come to be made, the exact
circumstances are forgotten; and hence, multitudinous as may be such
"spontaneous" variations, it is exceedingly difficult to get at the
origin of them.
The second case is one of which you may find the whole details in the
"Philosophical Transactions" for the year 1813, in a paper communicated
by Colonel Humphreys to the President of the Royal Society,--"On a new
Variety in the Breed of Sheep," giving an account of a very remarkable
breed of sheep, which at one time was well known in the northern states
of America, and which went by the name of the Ancon or the Otter breed
of sheep. In the year 1791, there was a farmer of the name of Seth
Wright in Massachusetts, who had a flock of sheep, consisting of a ram
and, I think, of some twelve or thirteen ewes. Of this flock of ewes,
one at the breeding-time bore a lamb which was very singularly formed;
it had a very long body, very short legs, and those legs were bowed! I
will tell you by-and-by how this singular variation in the breed of
sheep came to be noted, and to have the prominence that it now has. For
the present, I mention only these two cases; but the extent of variation
in the breed of animals is perfectly obvious to any one who has studied
natural history with ordinary attention, or to any person who compares
animals with others of the same kind. It is strictly true that there are
never any two specimens which are exactly alike; however similar, they
will always differ in some certain particular.
Now let us go back to Atavism,--to the hereditary tendency I spoke of.
What will come of a variation when you breed from it, when Atavism
comes, if I may say so, to intersect variation? The two cases of which I
have mentioned the history, give a most excellent illustration of what
occurs. Gratio Kelleia, the Maltese, married when he was twenty-two
years of age, and, as I suppose there were no six-fingered ladies in
Malta, he married an ordinary five-fingered person. The result of that
marriage was four children; the first, who was christened Salvator, had
six fingers and six toes, like his father; the second was George, who
had five fingers and toes, but one of them was deformed, showing a
tendency to variation; the third was Andrè; he had five fingers and five
toes, quite perfect; the fourth was a girl, Marie; she had five fingers
and five toes, but her thumbs were deformed, showing a tendency toward
the sixth.
These children grew up, and when they came to adult years, they all
married, and of course it happened that they all married five-fingered
and five-toed persons. Now let us see what were the results. Salvator
had four children; they were two boys, a girl, and another boy: the
first two boys and the girl were six-fingered and six-toed like their
grandfather; the fourth boy had only five fingers and five toes. George
had only four children: there were two girls with six fingers and six
toes; there was one girl with six fingers and five toes on the right
side, and five fingers and five toes on the left side, so that she was
half and half. The last, a boy, had five fingers and five toes. The
third, Andrè, you will recollect, was perfectly well-formed, and he had
many children whose hands and feet were all regularly developed. Marie,
the last, who, of course, married a man who had only five fingers, had
four children: the first, a boy, was born with six toes, but the other
three were normal.
Now observe what very extraordinary phenomena are presented here. You
have an accidental variation arising from what you may call a
monstrosity; you have that monstrosity tendency or variation diluted in
the first instance by an admixture with a female of normal construction,
and you would naturally expect that, in the results of such an union,
the monstrosity, if repeated, would be in equal proportion with the
normal type; that is to say, that the children would be half and half,
some taking the peculiarity of the father, and the others being of the
purely normal type of the mother; but you see we have a great
preponderance of the abnormal type. Well, this comes to be mixed once
more with the pure, the normal type, and the abnormal is again produced
in large proportion, notwithstanding the second dilution. Now what would
have happened if these abnormal types had intermarried with each other;
that is to say, suppose the two boys of Salvator had taken it into their
heads to marry their first cousins, the two first girls of George, their
uncle? You will remember that these are all of the abnormal type of
their grandfather. The result would probably have been, that their
offspring would have been in every case a further development of that
abnormal type. You see it is only in the fourth, in the person of Marie,
that the tendency, when it appears but slightly in the second
generation, is washed out in the third, while the progeny of Andrè, who
escaped in the first instance, escape altogether.
We have in this case a good example of nature's tendency to the
perpetuation of a variation. Here it is certainly a variation which
carried with it no use or benefit; and yet you see the tendency to
perpetuation may be so strong, that, notwithstanding a great admixture
of pure blood, the variety continues itself up to the third generation,
which is largely marked with it. In this case, as I have said, there was
no means of the second generation intermarrying with any but
five-fingered persons, and the question naturally suggests itself, What
would have been the result of such marriage? Réaumur narrates this case
only as far as the third generation. Certainly it would have been an
exceedingly curious thing if we could have traced this matter any
further; had the cousins intermarried, a six-fingered variety of the
human race might have been set up.
To show you that this supposition is by no means an unreasonable one,
let me now point out what took place in the case of Seth Wright's sheep,
where it happened to be a matter of moment to him to obtain a breed or
raise a flock of sheep like that accidental variety that I have
described--and I will tell you why. In that part of Massachusetts where
Seth Wright was living, the fields were separated by fences, and the
sheep, which were very active and robust, would roam abroad, and without
much difficulty jump over these fences into other people's farms. As a
matter of course, this exuberant activity on the part of the sheep
constantly gave rise to all sorts of quarrels, bickerings, and
contentions among the farmers of the neighbourhood; so it occurred to
Seth Wright, who was, like his successors, more or less 'cute, that if
he could get a stock of sheep like those with the bandy legs, they would
not be able to jump over the fences so readily; and he acted upon that
idea. He killed his old ram, and as soon as the young one arrived at
maturity, he bred altogether from it. The result was even more striking
than in the human experiment which I mentioned just now. Colonel
Humphreys testifies that it always happened that the offspring were
either pure Ancons or pure ordinary sheep; that in no case was there any
mixing of the Ancons with the others. In consequence of this, in the
course of a very few years, the farmer was able to get a very
considerable flock of this variety, and a large number of them were
spread throughout Massachusetts. Most unfortunately, however--I suppose
it was because they were so common--nobody took enough notice of them to
preserve their skeletons; and although Colonel Humphreys states that he
sent a skeleton to the President of the Royal Society at the same time
that he forwarded his paper, I am afraid that the variety has entirely
disappeared; for a short time after these sheep had become prevalent in
that district, the Merino sheep were introduced; and as their wool was
much more valuable, and as they were a quiet race of sheep, and showed
no tendency to trespass or jump over fences, the Otter breed of sheep,
the wool of which was inferior to that of the Merino, was gradually
allowed to die out.
You see that these facts illustrate perfectly well what may be done if
you take care to breed from stocks that are similar to each other. After
having got a variation, if, by crossing a variation with the original
stock, you multiply that variation, and then take care to keep that
variation distinct from the original stock, and make them breed
together,--then you may almost certainly produce a race whose tendency
to continue the variation is exceedingly strong.
This is what is called "selection"; and it is by exactly the same
process as that by which Seth Wright bred his Ancon sheep, that our
breeds of cattle, dogs, and fowls, are obtained. There are some
possibilities of exception, but still, speaking broadly, I may say that
this is the way in which all our varied races of domestic animals have
arisen; and you must understand that it is not one peculiarity or one
characteristic alone in which animals may vary. There is not a single
peculiarity or characteristic of any kind, bodily or mental, in which
offspring may not vary to a certain extent from the parent and other
animals.
Among ourselves this is well known. The simplest physical peculiarity is
mostly reproduced. I know a case of a woman who has the lobe of one of
her ears a little flattened. An ordinary observer might scarcely notice
it, and yet every one of her children has an approximation to the same
peculiarity to some extent. If you look at the other extreme, too, the
gravest diseases, such as gout, scrofula, and consumption, may be handed
down with just the same certainty and persistence as we noticed in the
perpetuation of the bandy legs of the Ancon sheep.
However, these facts are best illustrated in animals, and the extent of
the variation, as is well known, is very remarkable in dogs. For
example, there are some dogs very much smaller than others; indeed, the
variation is so enormous that probably the smallest dog would be about
the size of the head of the largest; there are very great variations in
the structural forms not only of the skeleton but also in the shape of
the skull, and in the proportions of the face and the disposition of the
teeth.
The Pointer, the Retriever, Bulldog, and the Terrier, differ very
greatly, and yet there is every reason to believe that every one of
these races has arisen from the same source,--that all the most
important races have arisen by this selective breeding from accidental
variation.
A still more striking case of what may be done by selective breeding,
and it is a better case, because there is no chance of that partial
infusion of error to which I alluded, has been studied very carefully by
Mr. Darwin,--the case of the domestic pigeons. I dare say there may be
some among you who may be pigeon _fanciers_, and I wish you to
understand that in approaching the subject, I would speak with all
humility and hesitation, as I regret to say that I am not a pigeon
fancier. I know it is a great art and mystery, and a thing upon which a
man must not speak lightly; but I shall endeavour, as far as my
understanding goes, to give you a summary of the published and
unpublished information which I have gained from Mr. Darwin.
Among the enormous variety,--I believe there are somewhere about a
hundred and fifty kinds of pigeons,--there are four kinds which may be
selected as representing the extremest divergences of one kind from
another. Their names are the Carrier, the Pouter, the Fantail, and the
Tumbler. In these large diagrams that I have here they are each
represented in their relative sizes to each other. This first one is the
Carrier; you will notice this large excrescence on its beak; it has a
comparatively small head; there is a bare space round the eyes; it has a
long neck, a very long beak, very strong legs, large feet, long wings,
and so on. The second one is the Pouter, a very large bird, with very
long legs and beak. It is called the Pouter because it is in the habit
of causing its gullet to swell up by inflating it with air. I should
tell you that all pigeons have a tendency to do this at times, but in
the Pouter it is carried to an enormous extent. The birds appear to be
quite proud of their power of swelling and puffing themselves out in
this way; and I think it is about as droll a sight as you can well see
to look at a cage full of these pigeons puffing and blowing themselves
out in this ridiculous manner.
This diagram is a representation of the third kind I mentioned--the
Fantail. It is, you see, a small bird, with exceedingly small legs and a
very small beak. It is most curiously distinguished by the size and
extent of its tail, which, instead of containing twelve feathers, may
have many more,--say thirty, or even more--I believe there are some with
as many as forty-two. This bird has a curious habit of spreading out the
feathers of its tail in such a way that they reach forward, and touch
its head; and if this can be accomplished, I believe it is looked upon
as a point of great beauty.
But here is the last great variety,--the Tumbler; and of that great
variety, one of the principal kinds, and one most prized, is the
specimen represented here--the short-faced Tumbler. Its beak, you see,
is reduced to a mere nothing. Just compare the beak of this one and that
of the first one, the Carrier--I believe the orthodox comparison of the
head and beak of a thoroughly well-bred Tumbler is to stick an oat into
a cherry, and that will give you the proper relative proportions of the
beak and head. The feet and legs are exceedingly small, and the bird
appears to be quite a dwarf when placed side by side with this great
Carrier.
These are differences enough in regard to their external appearance; but
these differences are by no means the whole or even the most important
of the differences which obtain between these birds. There is hardly a
single point of their structure which has not become more or less
altered; and to give you an idea of how extensive these alterations are,
I have here some very good skeletons, for which I am indebted to my
friend Mr. Tegetmeier, a great authority in these matters; by means of
which, if you examine them by-and-by, you will be able to see the
enormous difference in their bony structures.
I had the privilege, some time ago, of access to some important MSS. of
Mr. Darwin, who, I may tell you, has taken very great pains and spent
much valuable time and attention on the investigation of these
variations, and getting together all the facts that bear upon them. I
obtained from these MSS. the following summary of the differences
between the domestic breeds of pigeons; that is to say, a notification
of the various points in which their organization differs. In the first
place, the back of the skull may differ a good deal, and the development
of the bones of the face may vary a great deal; the back varies a good
deal; the shape of the lower jaw varies; the tongue varies very greatly,
not only in correlation to the length and size of the beak, but it seems
also to have a kind of independent variation of its own. Then the amount
of naked skin round the eyes, and at the base of the beak, may vary
enormously; so may the length of the eyelids, the shape of the nostrils,
and the length of the neck. I have already noticed the habit of blowing
out the gullet, so remarkable in the Pouter, and comparatively so in the
others. There are great differences, too, in the size of the female and
the male, the shape of the body, the number and width of the processes
of the ribs, the development of the ribs, and the size, shape, and
development of the breastbone. We may notice, too,--and I mention the
fact because it has been disputed by what is assumed to be high
authority,--the variation in the number of the sacral vertebræ. The
number of these varies from eleven to fourteen, and that without any
diminution in the number of the vertebræ of the back or of the tail.
Then the number and position of the tail-feathers may vary enormously,
and so may the number of the primary and secondary feathers of the
wings. Again, the length of the feet and of the beak,--although they
have no relation to each other, yet appear to go together,--that is, you
have a long beak wherever you have long feet. There are differences also
in the periods of the acquirement of the perfect plumage,--the size and
shape of the eggs,--the nature of flight, and the powers of
flight,--so-called "_homing_" birds having enormous flying powers;[52]
while, on the other hand, the little Tumbler is so called because of its
extraordinary faculty of turning head over heels in the air, instead of
pursuing a distinct course. And, lastly, the dispositions and voices of
the birds may vary. Thus the case of the pigeons shows you that there is
hardly a single particular,--whether of instinct, or habit, or bony
structure, or of plumage,--of either the internal economy or the
external shape, in which some variation or change may not take place,
which, by selective breeding, may become perpetuated, and form the
foundation of, and give rise to, a new race.
If you carry in your mind's eye these four varieties of pigeons, you
will bear with you as good a notion as you can have, perhaps, of the
enormous extent to which a deviation from a primitive type may be
carried by means of this process of selective breeding.
FOOTNOTES:
[52] The "_Carrier_," I learn from Mr. Tegetmeier, does not _carry_; a
high-bred bird of this breed being but a poor flier. The birds which fly
long distances, and come home,--"homing" birds,--and are consequently
used as carriers, are not "carriers" in the fancy sense.
VIII
THE CONDITIONS OF EXISTENCE AS AFFECTING
THE PERPETUATION OF LIVING
BEINGS.
In the last Lecture I endeavoured to prove to you that, while, as a
general rule, organic beings tend to reproduce their kind, there is in
them, also, a constantly recurring tendency to vary--to vary to a
greater or to a less extent. Such a variety, I pointed out to you, might
arise from causes which we do not understand; we therefore called it
spontaneous; and it might come into existence as a definite and marked
thing, without any gradations between itself and the form which preceded
it. I further pointed out, that such a variety having once arisen, might
be perpetuated to some extent, and indeed to a very marked extent,
without any direct interference, or without any exercise of that process
which we called selection. And then I stated further, that by such
selection, when exercised artificially--if you took care to breed only
from those forms which presented the same peculiarities of any variety
which had arisen in this manner--the variation might be perpetuated, as
far as we can see, indefinitely.
The next question, and it is an important one for us, is this: Is there
any limit to the amount of variation from the primitive stock which can
be produced by this process of selective breeding? In considering this
question, it will be useful to class the characteristics, in respect of
which organic beings vary, under two heads: we may consider structural
characteristics, and we may consider physiological characteristics.
In the first place, as regards structural characteristics, I endeavoured
to show you, by the skeletons which I had upon the table, and by
reference to a great many well-ascertained facts, that the different
breeds of Pigeons, the Carriers, Pouters, and Tumblers, might vary in
any of their internal and important structural characters to a very
great degree; not only might there be changes in the proportions of the
skull, and the characters of the feet and beaks, and so on; but that
there might be an absolute difference in the number of the vertebræ of
the back, as in the sacral vertebræ of the Pouter; and so great is the
extent of the variation in these and similar characters that I pointed
out to you, by reference to the skeletons and the diagrams, that these
extreme varieties may absolutely differ more from one another in their
structural characters than do what naturalists call distinct SPECIES of
pigeons; that is to say, that they differ so much in structure that
there is a greater difference between the Pouter and the Tumbler than
there is between such wild and distinct forms as the Rock Pigeon or the
Ring Pigeon, or the Ring Pigeon and the Stock Dove; and indeed the
differences are of greater value than this, for the structural
differences between these domesticated pigeons are such as would be
admitted by a naturalist, supposing he knew nothing at all about their
origin, to entitle them to constitute even distinct genera.
As I have used this term SPECIES, and shall probably use it a good deal,
I had better perhaps devote a word or two to explaining what I mean by
it.
Animals and plants are divided into groups, which become gradually
smaller, beginning with a KINGDOM, which is divided into SUB-KINGDOMS;
then come the smaller divisions called PROVINCES; and so on from a
PROVINCE to a CLASS, from a CLASS to an ORDER, from _Orders_ to
_Families_, and from these to GENERA, until we come at length to the
smallest groups of animals which can be defined one from the other by
constant characters, which are not sexual; and these are what
naturalists call SPECIES in practice, whatever they may do in theory.
If in a state of nature you find any two groups of living beings, which
are separated one from the other by some constantly-recurring
characteristic, I don't care how slight and trivial, so long as it is
defined and constant, and does not depend on sexual peculiarities, then
all naturalists agree in calling them two species; that is what is meant
by the use of the word species--that is to say, it is, for the practical
naturalist, a mere question of structural differences.[53]
We have seen now--to repeat this point once more, and it is very
essential that we should rightly understand it--we have seen that
breeds, known to have been derived from a common stock by selection, may
be as different in their structure from the original stock as species
may be distinct from each other.
But is the like true of the physiological characteristics of animals? Do
the physiological differences of varieties amount in degree to those
observed between forms which naturalists call distinct species? This is
a most important point for us to consider.
As regards the great majority of physiological characteristics, there is
no doubt that they are capable of being developed, increased, and
modified by selection.
There is no doubt that breeds may be made as different as species in
many physiological characters. I have already pointed out to you very
briefly the different habits of the breeds of Pigeons, all of which
depend upon their physiological peculiarities,--as the peculiar habit of
tumbling, in the Tumbler,--the peculiarities of flight, in the "homing"
birds,--the strange habit of spreading out the tail, and walking in a
peculiar fashion, in the Fantail,--and, lastly, the habit of blowing out
the gullet, so characteristic of the Pouter. These are all due to
physiological modifications, and in all these respects these birds
differ as much from each other as any two ordinary species do.
So with Dogs in their habits and instincts. It is a physiological
peculiarity which leads the Greyhound to chase its prey by sight,--that
enables the Beagle to track it by the scent,--that impels the Terrier to
its rat-hunting propensity,--and that leads the Retriever to its habits
of retrieving. These habits and instincts are all the results of
physiological differences and peculiarities, which have been developed
from a common stock, at least there is every reason to believe so. But
it is a most singular circumstance, that while you may run through
almost the whole series of physiological processes, without finding a
check to your argument, you come at last to a point where you do find a
check, and that is in the reproductive processes. For there is a most
singular circumstance in respect to natural species--at least about some
of them--and it would be sufficient for the purposes of this argument,
if it were true of only one of them, but there is, in fact, a great
number of such cases--and that is, that similar as they may appear to be
to mere races or breeds, they present a marked peculiarity in the
reproductive process. If you breed from the male and female of the same
race, you of course have offspring of the like kind, and if you make the
offspring breed together, you obtain the same result, and if you breed
from these again, you will still have the same kind of offspring; there
is no check. But if you take members of two distinct species, however
similar they may be to each other, and make them breed together, you
will find a check, with some modifications and exceptions, however,
which I shall speak of presently. If you cross two such species with
each other, then,--although you may get offspring in the case of the
first cross, yet, if you attempt to breed from the products of that
crossing, which are what are called HYBRIDS--that is, if you couple a
male and a female hybrid--then the result is that in ninety-nine cases
out of a hundred you will get no offspring at all: there will be no
result whatsoever.
The reason of this is quite obvious in some cases; the male hybrids,
although possessing all the external appearances and characteristics of
perfect animals, are physiologically imperfect and deficient in the
structural parts of the reproductive elements necessary to generation.
It is said to be invariably the case with the male mule, the cross
between the Ass and the Mare; and hence it is, that, although crossing
the Horse with the Ass is easy enough, and is constantly done, as far
as I am aware, if you take two mules, a male and a female, and endeavour
to breed from them, you get no offspring whatever; no generation will
take place. This is what is called the sterility of the hybrids between
two distinct species.
You see that this is a very extraordinary circumstance; one does not see
why it should be. The common teleological explanation is, that it is to
prevent the impurity of the blood resulting from the crossing of one
species with another, but you see it does not in reality do anything of
the kind. There is nothing in this fact that hybrids cannot breed with
each other, to establish such a theory; there is nothing to prevent the
Horse breeding with the Ass, or the Ass with the Horse. So that this
explanation breaks down, as a great many explanations of this kind do,
that are only founded on mere assumptions.
Thus you see that there is a great difference between "mongrels," which
are crosses between distinct races, and "hybrids," which are crosses
between distinct species. The mongrels are, so far as we know, fertile
with one another. But between species, in many cases, you cannot succeed
in obtaining even the first cross: at any rate it is quite certain that
the hybrids are often absolutely infertile one with another.
Here is a feature, then, great or small as it may be, which
distinguishes natural species of animals. Can we find any approximation
to this in the different races known to be produced by selective
breeding from a common stock? Up to the present time the answer to that
question is absolutely a negative one. As far as we know at present,
there is nothing approximating to this check. In crossing the breeds
between the Fantail and the Pouter, the Carrier and the Tumbler, or any
other variety or race you may name--so far as we know at present--there
is no difficulty in breeding together the mongrels. Take the Carrier and
the Fantail, for instance, and let them represent the Horse and the Ass
in the case of distinct species; then you have, as the result of their
breeding, the Carrier-Fantail mongrel,--we will say the male and female
mongrel,--and, as far as we know, these two when crossed would not be
less fertile than the original cross, or than Carrier with Carrier.
Here, you see, is a physiological contrast between the races produced by
selective modification and natural species. I shall inquire into the
value of this fact, and of some modifying circumstances by and by; for
the present I merely put it broadly before you.
But while considering this question of the limitations of species, a
word must be said about what is called RECURRENCE--the tendency of races
which have been developed by selective breeding from varieties to return
to their primitive type. This is supposed by many to put an absolute
limit to the extent of selective and all other variations. People say,
"It is all very well to talk about producing these different races, but
you know very well that if you turned all these birds wild, these
Pouters, and Carriers, and so on, they would all return to their
primitive stock." This is very commonly assumed to be a fact, and it is
an argument that is commonly brought forward as conclusive; but if you
will take the trouble to inquire into it rather closely, I think you
will find that it is not worth very much. The first question of course
is, Do they thus return to the primitive stock? And commonly as the
thing is assumed and accepted, it is extremely difficult to get anything
like good evidence of it. It is constantly said, for example, that if
domesticated Horses are turned wild, as they have been in some parts of
Asia Minor and South America, that they return at once to the primitive
stock from which they were bred. But the first answer that you make to
this assumption is, to ask who knows what the primitive stock was; and
the second answer is, that in that case the wild Horses of Asia Minor
ought to be exactly like the wild Horses of South America. If they are
both like the same thing, they ought manifestly to be like each other!
The best authorities, however, tell you that it is quite different. The
wild Horse of Asia is said to be of a dun colour, with a largish head,
and a great many other peculiarities; while the best authorities on the
wild Horses of South America tell you that there is no similarity
between their wild Horses and those of Asia Minor; the cut of their
heads is very different, and they are commonly chestnut or
bay-coloured. It is quite clear, therefore, that as by these facts there
ought to have been two primitive stocks, they go for nothing in support
of the assumption that races recur to one primitive stock, and so far as
this evidence is concerned, it falls to the ground.
Suppose for a moment that it were so, and that domesticated races, when
turned wild, did return to some common condition, I cannot see that this
would prove much more than that similar conditions are likely to produce
similar results; and that when you take back domesticated animals into
what we call natural conditions, you do exactly the same thing as if you
carefully undid all the work you had gone through, for the purpose of
bringing the animal from its wild to its domesticated state. I do not
see anything very wonderful in the fact, if it took all that trouble to
get it from a wild state, that it should go back into its original state
as soon as you removed the conditions which produced the variation to
the domesticated form. There is an important fact, however, forcibly
brought forward by Mr. Darwin, which has been noticed in connection with
the breeding of domesticated pigeons; and it is, that however different
these breeds of pigeons may be from each other, and we have already
noticed the great differences in these breeds, that if, among any of
those variations, you chance to have a blue pigeon turn up, it will be
sure to have the black bars across the wings, which are characteristic
of the original wild stock, the Rock Pigeon.
Now, this is certainly a very remarkable circumstance; but I do not see
myself how it tells very strongly either one way or the other. I think,
in fact, that this argument in favour of recurrence to the primitive
type might prove a great deal too much for those who so constantly bring
it forward. For example, Mr. Darwin has very forcibly urged, that
nothing is commoner than if you examine a dun horse--and I had an
opportunity of verifying this illustration lately, while in the islands
of the West Highlands, where there are a great many dun horses--to find
that horse exhibit a long black stripe down his back, very often stripes
on his shoulder, and very often stripes on his legs. I, myself, saw a
pony of this description a short time ago, in a baker's cart, near
Rothesay, in Bute: it had the long stripe down the back, and stripes on
the shoulders and legs, just like those of the Ass, the Quagga, and the
Zebra. Now, if we interpret the theory of recurrence as applied to this
case, might it not be said that here was a case of a variation
exhibiting the characters and conditions of an animal occupying
something like an intermediate position between the Horse, the Ass, the
Quagga, and the Zebra, and from which these had been developed? In the
same way with regard even to Man. Every anatomist will tell you that
there is nothing commoner, in dissecting the human body, than to meet
with what are called muscular variations--that is, if you dissect two
bodies very carefully, you will probably find that the modes of
attachment and insertion of the muscles are not exactly the same in
both, there being great peculiarities in the mode in which the muscles
are arranged; and it is very singular, that in some dissections of the
human body you will come upon arrangements of the muscles very similar
indeed to the same parts in the Apes. Is the conclusion in that case to
be, that this is like the black bars in the case of the Pigeon, and that
it indicates a recurrence to the primitive type from which the animals
have been probably developed? Truly, I think that the opponents of
modification and variation had better leave the argument of recurrence
alone, or it may prove altogether too strong for them.
To sum up,--the evidence as far as we have gone is against the argument
as to any limit to divergences, so far as structure is concerned; and in
favour of a physiological limitation. By selective breeding we can
produce structural divergences as great as those of species, but we
cannot produce equal physiological divergences. For the present I leave
the question there.
Now, the next problem that lies before us--and it is an extremely
important one--is this: Does this selective breeding occur in nature?
Because, if there is no proof of it, all that I have been telling you
goes for nothing in accounting for the origin of species. Are natural
causes competent to play the part of selection in perpetuating
varieties? Here we labour under very great difficulties. In the last
lecture I had occasion to point out to you the extreme difficulty of
obtaining evidence even of the first origin of those varieties which we
know to have occurred in domesticated animals. I told you, that almost
always the origin of these varieties is overlooked, so that I could only
produce two or three cases, as that of Gratio Kelleia and of the Ancon
sheep. People forget, or do not take notice of them until they come to
have a prominence; and if that is true of artificial cases, under our
own eyes, and in animals in our own care, how much more difficult it
must be to have at first hand good evidence of the origin of varieties
in nature! Indeed, I do not know that it is possible by direct evidence
to prove the origin of a variety in nature, or to prove selective
breeding; but I will tell you what we can prove--and this comes to the
same thing--that varieties exist in nature within the limits of species,
and, what is more, that when a variety has come into existence in
nature, there are natural causes and conditions, which are amply
competent to play the part of a selective breeder; and although that is
not quite the evidence that one would like to have--though it is not
direct testimony--yet it is exceeding good and exceedingly powerful
evidence in its way.
As to the first point, of varieties existing among natural species, I
might appeal to the universal experience of every naturalist, and of any
person who has ever turned any attention at all to the characteristics
of plants and animals in a state of nature; but I may as well take a few
definite cases, and I will begin with Man himself.
I am one of those who believe that, at present, there is no evidence
whatever for saying, that mankind sprang originally from any more than a
single pair; I must say, that I cannot see any good ground whatever, or
even any tenable sort of evidence, for believing that there is more than
one species of Man. Nevertheless, as you know, just as there are numbers
of varieties in animals, so there are remarkable varieties of men. I
speak not merely of those broad and distinct variations which you see at
a glance. Everybody, of course, knows the difference between a Negro
and a white man, and can tell a Chinaman from an Englishman. They each
have peculiar characteristics of colour and physiognomy; but you must
recollect that the characters of these races go very far deeper--they
extend to the bony structure, and to the characters of that most
important of all organs to us--the brain; so that, among men belonging
to different races, or even within the same race, one man shall have a
brain a third, or half, or even seventy per cent bigger than another;
and if you take the whole range of human brains, you will find a
variation in some cases of a hundred per cent. Apart from these
variations in the size of the brain, the characters of the skull vary.
Thus if I draw the figures of a Mongul and of a Negro head on the
blackboard, in the case of the last the breadth would be about
seven-tenths, and in the other it would be nine-tenths of the total
length. So that you see there is abundant evidence of variation among
men in their natural condition. And if you turn to other animals there
is just the same thing. The fox, for example, which has a very large
geographical distribution all over Europe, and parts of Asia, and on the
American Continent, varies greatly. There are mostly large foxes in the
North, and smaller ones in the South. In Germany alone, the foresters
reckon some eight different sorts.
Of the tiger, no one supposes that there is more than one species; they
extend from the hottest parts of Bengal, into the dry, cold, bitter
steppes of Siberia, into a latitude of 50°,--so that they may even prey
upon the reindeer. These tigers have exceedingly different
characteristics, but still they all keep their general features, so that
there is no doubt as to their being tigers. The Siberian tiger has a
thick fur, a small mane, and a longitudinal stripe down the back, while
the tigers of Java and Sumatra differ in many important respects from
the tigers of Northern Asia. So lions vary; so birds vary; and so, if
you go further back and lower down in creation, you find that fishes
vary. In different streams, in the same country even, you will find the
trout to be quite different to each other and easily recognizable by
those who fish in the particular streams. There is the same differences
in leeches; leech collectors can easily point out to you the differences
and the peculiarities which you yourself would probably pass by; so with
fresh-water mussels; so, in fact, with every animal you can mention.
In plants there is the same kind of variation. Take such a case even as
the common bramble. The botanists are all at war about it; some of them
wanting to make out that there are many species of it, and others
maintaining that they are but many varieties of one species; and they
cannot settle to this day which is a species and which is a variety!
So that there can be no doubt whatsoever that any plant and any animal
may vary in nature; that varieties may arise in the way I have
described,--as spontaneous varieties,--and that those varieties may be
perpetuated in the same way that I have shown you spontaneous varieties
are perpetuated; I say, therefore, that there can be no doubt as to the
origin and perpetuation of varieties in nature.
But the question now is:--Does selection take place in nature? is there
anything like the operation of man in exercising selective breeding,
taking place in nature? You will observe that, at present, I say nothing
about species; I wish to confine myself to the consideration of the
production of those natural races which everybody admits to exist. The
question is, whether in nature there are causes competent to produce
races, just in the same way as man is able to produce, by selection,
such races of animals as we have already noticed.
When a variety has arisen, the CONDITIONS OF EXISTENCE are such as to
exercise an influence which is exactly comparable to that of artificial
selection. By Conditions of Existence I mean two things,--there are
conditions which are furnished by the physical, the inorganic world, and
there are conditions of existence which are furnished by the organic
world. There is, in the first place, CLIMATE; under that head I include
only temperature and the varied amount of moisture of particular places.
In the next place there is what is technically called STATION, which
means--given the climate, the particular kind of place in which an
animal or a plant lives or grows; for example, the station of a fish is
in the water, of a fresh-water fish in fresh water; the station of a
marine fish is in the sea, and a marine animal may have a station higher
or deeper. So again with land animals: the differences in their stations
are those of different soils and neighbourhoods; some being best adapted
to a calcareous, and others to an arenaceous soil. The third condition
of existence is FOOD, by which I mean food in the broadest sense, the
supply of the materials necessary to the existence of an organic being;
in the case of a plant the inorganic matters, such as carbonic acid,
water, ammonia, and the earthy salts or salines; in the case of the
animal the inorganic and organic matters, which we have seen they
require; then these are all, at least the two first, what we may call
the inorganic or physical conditions of existence. Food takes a
mid-place, and then come the organic conditions; by which I mean the
conditions which depend upon the state of the rest of the organic
creation, upon the number and kind of living beings, with which an
animal is surrounded. You may class these under two heads: there are
organic beings, which operate as _opponents_, and there are organic
beings which operate as _helpers_ to any given organic creature. The
opponents may be of two kinds: there are the _indirect opponents_, which
are what we may call _rivals_; and there are the _direct opponents_,
those which strive to destroy the creature; and these we call _enemies_.
By rivals I mean, of course, in the case of plants, those which require
for their support the same kind of soil and station, and, among animals,
those which require the same kind of station, or food, or climate; those
are the indirect opponents; the direct opponents are, of course, those
which prey upon an animal or vegetable. The _helpers_ may also be
regarded as direct and indirect: in the case of a carnivorous animal,
for example, a particular herbaceous plant may in multiplying be an
indirect helper, by enabling the herbivora on which the carnivore preys
to get more food, and thus to nourish the carnivore more abundantly; the
direct helper may be best illustrated by reference to some parasitic
creature, such as the tape-worm. The tape-worm exists in the human
intestines, so that the fewer there are of men the fewer there will be
of tape-worms, other things being alike. It is a humiliating reflection,
perhaps, that we may be classed as direct helpers to the tape-worm, but
the fact is so: we can all see that if there were no men there would be
no tape-worms.
It is extremely difficult to estimate, in a proper way, the importance
and the working of the Conditions of Existence. I do not think there
were any of us who had the remotest notion of properly estimating them
until the publication of Mr. Darwin's work, which has placed them before
us with remarkable clearness; and I must endeavour, as far as I can in
my own fashion, to give you some notion of how they work. We shall find
it easiest to take a simple case, and one as free as possible from every
kind of complication.
I will suppose, therefore, that all the habitable part of this
globe--the dry land, amounting to about 51,000,000 square miles,--I will
suppose that the whole of that dry land has the same climate, and that
it is composed of the same kind of rock or soil, so that there will be
the same station everywhere; we thus get rid of the peculiar influence
of different climates and stations. I will then imagine that there shall
be but one organic being in the world, and that shall be a plant. In
this we start fair. Its food is to be carbonic acid, water and ammonia,
and the saline matters in the soil, which are, by the supposition,
everywhere alike. We take one single plant, with no opponents, no
helpers, and no rivals; it is to be a "fair field, and no favour." Now,
I will ask you to imagine further that it shall be a plant which shall
produce every year fifty seeds, which is a very moderate number for a
plant to produce; and that, by the action of the winds and currents,
these seeds shall be equally and gradually distributed over the whole
surface of the land. I want you now to trace out what will occur, and
you will observe that I am not talking fallaciously any more than a
mathematician does when he expounds his problem. If you show that the
conditions of your problem are such as may actually occur in nature and
do not transgress any of the known laws of nature in working out your
proposition, then you are as safe in the conclusion you arrive at as is
the mathematician in arriving at the solution of his problem. In
science, the only way of getting rid of the complications with which a
subject of this kind is environed, is to work in this deductive method.
What will be the result, then? I will suppose that every plant requires
one square foot of ground to live upon; and the result will be that, in
the course of nine years, the plant will have occupied every single
available spot in the whole globe! I have chalked upon the blackboard
the figures by which I arrive at the result:--
Plants. Plants.
1 × 50 in 1st year = 50
50 × 50 " 2nd " = 2,500
2,500 × 50 " 3rd " = 125,000
125,000 × 50 " 4th " = 6,250,000
6,250,000 × 50 " 5th " = 312,500,000
312,500,000 × 50 " 6th " = 15,625,000,000
15,625,000,000 × 50 " 7th " = 781,250,000,000
781,250,000,000 × 50 " 8th " = 39,062,500,000,000
39,062,500,000,000 × 50 " 9th " = 1,953,125,000,000,000
51,000,000 sq. miles--the dry surface}
of the earth × 27,878,400--the } = sq. ft. 1,421,798,400,000,000
number of sq. ft. in 1 sq. mile } ---------------------
being 531,326,600,000,000
square feet less than would be required at the end of the ninth year.
You will see from this that, at the end of the first year the single
plant will have produced fifty more of its kind; by the end of the
second year these will have increased to 2500; and so on, in succeeding
years, you get beyond even trillions; and I am not at all sure that I
could tell you what the proper arithmetical denomination of the total
number really is; but, at any rate, you will understand the meaning of
all those noughts. Then you see that, at the bottom, I have taken the
51,000,000 of square miles, constituting the surface of the dry land;
and as the number of square feet are placed under and subtracted from
the number of seeds that would be produced in the ninth year, you can
see at once that there would be an immense number more of plants than
there would be square feet of ground for their accommodation. This is
certainly quite enough to prove my point; that between the eighth and
ninth year after being planted the single plant would have stocked the
whole available surface of the earth.
This is a thing which is hardly conceivable--it seems hardly
imaginable--yet it is so. It is indeed simply the law of Malthus
exemplified. Mr. Malthus was a clergy-man, who worked out this subject
most minutely and truthfully some years ago; he showed quite
clearly,--and although he was much abused for his conclusions at the
time, they have never yet been disproved and never will be--he showed
that in consequence of the increase in the number of organic beings in a
geometrical ratio, while the means of existence cannot be made to
increase in the same ratio, that there must come a time when the number
of organic beings will be in excess of the power of production of
nutriment, and that thus some check must arise to the further increase
of those organic beings. At the end of the ninth year we have seen that
each plant would not be able to get its full square foot of ground, and
at the end of another year it would have to share that space with fifty
others the produce of the seeds which it would give off.
What, then, takes place? Every plant grows up, flourishes, occupies its
square foot of ground, and gives off its fifty seeds; but notice this,
that out of this number only one can come to anything; there is thus, as
it were, forty-nine chances to one against its growing up; it depends
upon the most fortuitous circumstances whether any one of these fifty
seeds shall grow up and flourish, or whether it shall die and perish.
This is what Mr. Darwin has drawn attention to, and called the "STRUGGLE
FOR EXISTENCE"; and I have taken this simple case of a plant because
some people imagine that the phrase seems to imply a sort of fight.
I have taken this plant and shown you that this is the result of the
ratio of the increase, the necessary result of the arrival of a time
coming for every species when exactly as many members must be destroyed
as are born; that is the inevitable ultimate result of the rate of
production. Now, what is the result of all this? I have said that there
are forty-nine struggling against every one; and it amounts to this,
that the smallest possible start given to any one seed may give it an
advantage which will enable it to get ahead of all the others; anything
that will enable any one of these seeds to germinate six hours before
any of the others will, other things being alike, enable it to choke
them out altogether. I have shown you that there is no particular in
which plants will not vary from each other; it is quite possible that
one of our imaginary plants may vary in such a character as the
thickness of the integument of its seeds; it might happen that one of
the plants might produce seeds having a thinner integument, and that
would enable the seeds of that plant to germinate a little quicker than
those of any of the others, and those seeds would most inevitably
extinguish the forty-nine times as many that were struggling with them.
I have put it in this way, but you see the practical result of the
process is the same as if some person had nurtured the one and destroyed
the other seeds. It does not matter how the variation is produced, so
long as it is once allowed to occur. The variation in the plant once
fairly started tends to become hereditary and reproduce itself; the
seeds would spread themselves in the same way and take part in the
struggle with the forty-nine hundred, or forty-nine thousand, with which
they might be exposed. Thus, by degrees, this variety with some slight
organic change or modification, must spread itself over the whole
surface of the habitable globe, and extirpate or replace the other
kinds. That is what is meant by NATURAL SELECTION; that is the kind of
argument by which it is perfectly demonstrable that the conditions of
existence may play exactly the same part for natural varieties as man
does for domesticated varieties. No one doubts at all that particular
circumstances may be more favourable for one plant and less so for
another, and the moment you admit that, you admit the selective power of
nature. Now, although I have been putting a hypothetical case, you must
not suppose that I have been reasoning hypothetically. There are plenty
of direct experiments which bear out what we may call the theory of
natural selection; there is extremely good authority for the statement
that if you take the seed of mixed varieties of wheat and sow it,
collecting the seed next year and sowing it again, at length you will
find that out of all your varieties only two or three have lived, or
perhaps even only one. There were one or two varieties which were best
fitted to get on, and they have killed out the other kinds in just the
same way and with just the same certainty as if you had taken the
trouble to remove them. As I have already said, the operation of nature
is exactly the same as the artificial operation of man.
But if this be true of that simple case, which I put before you, where
there is nothing but the rivalry of one member of a species with others,
what must be the operation of selective conditions, when you recollect
as a matter of fact, that for every species of animal or plant there are
fifty or a hundred species which might all, more or less, be
comprehended in the same climate, food, and station;--that every plant
has multitudinous animals which prey upon it, and which are its direct
opponents; and that these have other animals preying upon them,--that
every plant has its indirect helpers in the birds that scatter abroad
its seed, and the animals that manure it with their dung;--I say, when
these things are considered, it seems impossible that any variation
which may arise in a species in nature should not tend in some way or
other either to be a little better or worse than the previous stock; if
it is a little better it will have an advantage over and tend to
extirpate the latter in this crush and struggle; and if it is a little
worse it will itself be extirpated.
I know nothing that more appropriately expresses this, than the phrase,
"the struggle for existence"; because it brings before your minds, in a
vivid sort of way, some of the simplest possible circumstances connected
with it. When a struggle is intense there must be some who are sure to
be trodden down, crushed, and overpowered by others; and there will be
some who just manage to get through only by the help of the slightest
accident. I recollect reading an account of the famous retreat of the
French troops, under Napoleon, from Moscow. Worn out, tired, and
dejected, they at length came to a great river over which there was but
one bridge for the passage of the vast army. Disorganized and
demoralized as that army was, the struggle must certainly have been a
terrible one--every one heeding only himself, and crushing through the
ranks and treading down his fellows. The writer of the narrative, who
was himself one of those who were fortunate enough to succeed in getting
over, and not among the thousands who were left behind or forced into
the river, ascribed his escape to the fact that he saw striding onward
through the mass a great strong fellow,--one of the French Cuirassiers,
who had on a large blue cloak--and he had enough presence of mind to
catch and retain a hold of this strong man's cloak. He says, "I caught
hold of his cloak, and although he swore at me and cut at and struck me
by turns, and at last, when he found he could not shake me off, fell to
entreating me to leave go or I should prevent him from escaping, besides
not assisting myself, I still kept tight hold of him, and would not quit
my grasp until he had at last dragged me through." Here you see was a
case of selective saving--if we may so term it--depending for its
success on the strength of the cloth of the Cuirassier's cloak. It is
the same in nature; every species has its bridge of Beresina; it has to
fight its way through and struggle with other species; and when well
nigh overpowered, it may be that the smallest chance, something in its
colour, perhaps--the minutest circumstance--will turn the scale one way
or the other.
Suppose that by a variation of the black race it had produced the white
man at any time--you know that the Negroes are said to believe this to
have been the case, and to imagine that Cain was the first white man,
and that we are his descendants--suppose that this had ever happened,
and that the first residence of this human being was on the West Coast
of Africa. There is no great structural difference between the white man
and the Negro, and yet there is something so singularly different in the
constitution of the two, that the malarias of that country, which do not
hurt the black at all, cut off and destroy the white. Then you see
there would have been a selective operation performed; if the white man
had risen in that way, he would have been selected out and removed by
means of the malaria. Now there really is a very curious case of
selection of this sort among pigs, and it is a case of selection of
colour, too. In the woods of Florida there are a great many pigs, and it
is a very curious thing that they are all black, every one of them.
Professor Wyman was there some years ago, and on noticing no pigs but
these black ones, he asked some of the people how it was that they had
no white pigs, and the reply was that in the woods of Florida there was
a root which they called the Paint Root, and that if the white pigs were
to eat any of it, it had the effect of making their hoofs crack, and
they died, but if the black pigs ate any of it, it did not hurt them at
all. Here was a very simple case of natural selection. A skilful breeder
could not more carefully develop the black breed of pigs, and weed out
all the white pigs, than the Paint Root does.
To show you how remarkably indirect may be such natural selective
agencies as I have referred to, I will conclude by noticing a case
mentioned by Mr. Darwin, and which is certainly one of the most curious
of its kind. It is that of the Humble Bee. It has been noticed that
there are a great many more humble bees in the neighbourhood of towns,
than out in the open country; and the explanation of the matter is this:
the humble bees build nests, in which they store their honey and deposit
the larvæ and eggs. The field mice are amazingly fond of the honey and
larvæ; therefore, wherever there are plenty of field mice, as in the
country, the humble bees are kept down; but in the neighbourhood of
towns, the number of cats which prowl about the fields eat up the field
mice, and of course the more mice they eat up the less there are to prey
upon the larvæ of the bees--the cats are therefore the INDIRECT HELPERS
of the bees.[54]
Coming back a step farther we may say that the old maids are also
indirect friends of the humble bees, and indirect enemies of the field
mice, as they keep the cats which eat up the latter! This is an
illustration somewhat beneath the dignity of the subject, perhaps, but
it occurs to me in passing, and with it I will conclude this lecture.
FOOTNOTES:
[53] I lay stress here on the _practical_ signification of "Species."
Whether a physiological test between species exist or not, it is hardly
ever applicable by the practical naturalist.
[54] The humble bees, on the other hand, are direct helpers of some
plants, such as the heartsease and red clover, which are fertilized by
the visits of the bees; and they are indirect helpers of the numerous
insects which are more or less completely supported by the heartsease
and red clover.
IX
A CRITICAL EXAMINATION OF THE POSITION OF MR. DARWIN'S WORK, "ON THE
ORIGIN OF SPECIES," IN RELATION TO THE COMPLETE THEORY OF THE CAUSES
OF THE PHENOMENA OF ORGANIC NATURE.
In the preceding lectures I have endeavoured to give you an account of
those facts, and of those reasonings from facts, which form the data
upon which all theories regarding the causes of the phenomena of organic
nature must be based. And, although I have had frequent occasion to
quote Mr. Darwin--as all persons hereafter, in speaking upon these
subjects, will have occasion to quote his famous book on the "Origin of
Species,"--you must yet remember that, wherever I have quoted him, it
has not been upon theoretical points, or for statements in any way
connected with his particular speculations, but on matters of fact,
brought forward by himself, or collected by himself, and which appear
incidentally in his book. If a man _will_ make a book, professing to
discuss a single question, an encyclopædia, I cannot help it.
Now, having had an opportunity of considering in this sort of way the
different statements bearing upon all theories whatsoever, I have to lay
before you, as fairly as I can, what is Mr. Darwin's view of the matter
and what position his theories hold, when judged by the principles which
I have previously laid down, as deciding our judgments upon all theories
and hypotheses.
I have already stated to you that the inquiry respecting the causes of
the phenomena of organic nature resolves itself into two problems--the
first being the question of the origination of living or organic
beings; and the second being the totally distinct problem of the
modification and perpetuation of organic beings when they have already
come into existence. The first question Mr. Darwin does not touch; he
does not deal with it at all; but he says:--"Given the origin of organic
matter--supposing its creation to have already taken place, my object is
to show in consequence of what laws and what demonstrable properties of
organic matter, and of its environments, such states of organic nature
as those with which we are acquainted must have come about." This, you
will observe, is a perfectly legitimate proposition; every person has a
right to define the limits of the inquiry which he sets before himself;
and yet it is a most singular thing that in all the multifarious, and,
not unfrequently, ignorant attacks which have been made upon the "Origin
of Species," there is nothing which has been more speciously criticised
than this particular limitation. If people have nothing else to urge
against the book, they say--"Well, after all, you see Mr. Darwin's
explanation of the 'Origin of Species' is not good for much, because, in
the long run, he admits that he does not know how organic matter began
to exist. But if you admit any special creation for the first particle
of organic matter you may just as well admit it for all the rest; five
hundred or five thousand distinct creations are just as intelligible,
and just as little difficult to understand, as one." The answer to these
cavils is two-fold. In the first place, all human inquiry must stop
somewhere; all our knowledge and all our investigation cannot take us
beyond the limits set by the finite and restricted character of our
faculties, or destroy the endless unknown, which accompanies, like its
shadow, the endless procession of phenomena. So far as I can venture to
offer an opinion on such a matter, the purpose of our being in
existence, the highest object that human beings can set before
themselves, is not the pursuit of any such chimera as the annihilation
of the unknown; but it is simply the unwearied endeavour to remove its
boundaries a little further from our little sphere of action.
I wonder if any historian would for a moment admit the objection, that
it is preposterous to trouble ourselves about the history of the Roman
Empire, because we do not know anything positive about the origin and
first building of the city of Rome! Would it be a fair objection to
urge, respecting the sublime discoveries of a Newton, or a Kepler, those
great philosophers, whose discoveries have been of the profoundest
benefit and service to all men,--to say to them--"After all that you
have told us as to how the planets revolve, and how they are maintained
in their orbits, you cannot tell us what is the cause of the origin of
the sun, moon, and stars. So what is the use of what you have done?" Yet
these objections would not be one whit more preposterous than the
objections which have been made to the "Origin of Species." Mr. Darwin,
then, had a perfect right to limit his inquiry as he pleased, and the
only question for us--the inquiry being so limited--is to ascertain
whether the method of his inquiry is sound or unsound; whether he has
obeyed the canons which must guide and govern all investigation, or
whether he has broken them; and it was because our inquiry this evening
is essentially limited to that question, that I spent a good deal of
time in a former lecture (which, perhaps some of you thought might have
been better employed) in endeavouring to illustrate the method and
nature of scientific inquiry in general. We shall now have to put in
practice the principles that I then laid down.
I stated to you in substance, if not in words, that wherever there are
complex masses of phenomena to be inquired into, whether they be
phenomena of the affairs of daily life, or whether they belong to the
more abstruse and difficult problems laid before the philosopher, our
course of proceeding in unravelling that complex chain of phenomena with
a view to get at its cause, is always the same; in all cases we must
invent an hypothesis; we must place before ourselves some more or less
likely supposition respecting that cause; and then, having assumed an
hypothesis, having supposed a cause for the phenomena in question, we
must endeavour, on the one hand, to demonstrate our hypothesis, or, on
the other, to upset and reject it altogether, by testing it in three
ways. We must, in the first place, be prepared to prove that the
supposed causes of the phenomena exist in nature; that they are what
the logicians call _vera causæ_--true causes;--in the next place, we
should be prepared to show that the assumed causes of the phenomena are
competent to produce such phenomena as those which we wish to explain by
them; and in the last place, we ought to be able to show that no other
known causes are competent to produce these phenomena. If we can succeed
in satisfying these three conditions we shall have demonstrated our
hypothesis; or rather I ought to say, we shall have proved it as far as
certainty is possible for us; for, after all, there is no one of our
surest convictions which may not be upset, or at any rate modified by a
further accession of knowledge. It was because it satisfied these
conditions that we accepted the hypothesis as to the disappearance of
the tea-pot and spoons in the case I supposed in a previous lecture; we
found that our hypothesis on that subject was tenable and valid, because
the supposed cause existed in nature, because it was competent to
account for the phenomena, and because no other known cause was
competent to account for them; and it is upon similar grounds that any
hypothesis you choose to name is accepted in science as tenable and
valid.
What is Mr. Darwin's hypothesis? As I apprehend it--for I have put it
into a shape more convenient for common purposes than I could find
_verbatim_ in his book--as I apprehend it, I say, it is, that all the
phenomena of organic nature, past and present, result from, or are
caused by, the inter-action of those properties of organic matter, which
we have called ATAVISM and VARIABILITY, with the CONDITIONS OF
EXISTENCE; or, in other words,--given the existence of organic matter,
its tendency to transmit its properties, and its tendency occasionally
to vary; and, lastly, given the conditions of existence by which organic
matter is surrounded--that these put together are the causes of the
Present and of the Past conditions of ORGANIC NATURE.
Such is the hypothesis as I understand it. Now let us see how it will
stand the various tests which I laid down just now. In the first place,
do these supposed causes of the phenomena exist in nature? Is it the
fact that in nature these properties of organic matter--atavism and
variability--and those phenomena which we have called the conditions of
existence,--is it true that they exist? Well, of course, if they do not
exist, all that I have told you in the last three or four lectures must
be incorrect, because I have been attempting to prove that they do
exist, and I take it that there is abundant evidence that they do exist;
so far, therefore, the hypothesis does not break down.
But in the next place comes a much more difficult inquiry:--Are the
causes indicated competent to give rise to the phenomena of organic
nature? I suspect that this is indubitable to a certain extent. It is
demonstrable, I think, as I have endeavoured to show you, that they are
perfectly competent to give rise to all the phenomena which are
exhibited by RACES in nature. Furthermore, I believe that they are quite
competent to account for all that we may call purely structural
phenomena which are exhibited by SPECIES in nature. On that point also I
have already enlarged somewhat. Again, I think that the causes assumed
are competent to account for most of the physiological characteristics
of species, and I not only think that they are competent to account for
them, but I think that they account for many things which otherwise
remain wholly unaccountable and inexplicable, and I may say
incomprehensible. For a full exposition of the grounds on which this
conviction is based, I must refer you to Mr. Darwin's work; all that I
can do now is to illustrate what I have said by two or three cases taken
almost at random.
I drew your attention, on a previous evening, to the facts which are
embodied in our systems of Classification, which are the results of the
examination and comparison of the different members of the animal
kingdom one with another. I mentioned that the whole of the animal
kingdom is divisible into five sub-kingdoms; that each of these
sub-kingdoms is again divisible into provinces; that each province may
be divided into classes, and the classes into the successively smaller
groups, orders, families, genera, and species.
Now, in each of these groups, the resemblance in structure among the
members of the group is closer in proportion as the group is smaller.
Thus, a man and a worm are members of the animal kingdom in virtue of
certain apparently slight though really fundamental resemblances which
they present. But a man and a fish are members of the same Sub-kingdom
_Vertebrata_, because they are much more like one another than either of
them is to a worm, or a snail, or any member of the other sub-kingdoms.
For similar reasons men and horses are arranged as members of the same
Class, _Mammalia_; men and apes as members of the same Order,
_Primates_; and if there were any animals more like men than they were
like any of the apes, and yet different from men in important and
constant particulars of their organization, we should rank them as
members of the same Family, or of the same Genus, but as of distinct
Species.
That it is possible to arrange all the varied forms of animals into
groups, having this sort of singular subordination one to the other, is
a very remarkable circumstance; but, as Mr. Darwin remarks, this is a
result which is quite to be expected, if the principles which he lays
down be correct. Take the case of the races which are known to be
produced by the operation of atavism and variability, and the conditions
of existence which check and modify these tendencies. Take the case of
the pigeons that I brought before you: there it was shown that they
might be all classed as belonging to some one of five principal
divisions, and that within these divisions other subordinate groups
might be formed. The members of these groups are related to one another
in just the same way as the genera of a family, and the groups
themselves as the families of an order, or the orders of a class; while
all have the same sort of structural relations with the wild
Rock-pigeon, as the members of any great natural group have with a real
or imaginary typical form. Now, we know that all varieties of pigeons of
every kind have arisen by a process of selective breeding from a common
stock, the Rock-pigeon; hence, you see, that if all species of animals
have proceeded from some common stock, the general character of their
structural relations, and of our systems of classification, which
express those relations, would be just what we find them to be. In
other words, the hypothetical cause is, so far, competent to produce
effects similar to those of the real cause.
Take, again, another set of very remarkable facts,--the existence of
what are called rudimentary organs, organs for which we can find no
obvious use, in the particular animal economy in which they are found,
and yet which are there.
Such are the splint-like bones in the leg of the horse, which I here
show you, and which correspond with bones which belong to certain toes
and fingers in the human hand and foot. In the horse you see they are
quite rudimentary, and bear neither toes nor fingers; so that the horse
has only one "finger" in his fore-foot and one "toe" in his hind-foot.
But it is a very curious thing that the animals closely allied to the
horse show more toes than he; as the rhinoceros, for instance: he has
these extra toes well formed, and anatomical facts show very clearly
that he is very closely related to the horse indeed. So we may say that
animals, in an anatomical sense nearly related to the horse, have those
parts which are rudimentary in him, fully developed.
Again, the sheep and the cow have no cutting-teeth, but only a hard pad
in the upper jaw. That is the common characteristic of ruminants in
general. But the calf has in its upper jaw some rudiments of teeth which
never are developed, and never play the part of teeth at all. Well, if
you go back in time, you find some of the older, now extinct, allies of
the ruminants have well-developed teeth in their upper jaws; and at the
present day the pig (which is in structure closely connected with
ruminants) has well-developed teeth in its upper jaw; so that here is
another instance of organs well developed and very useful, in one
animal, represented by rudimentary organs, for which we can discover no
purpose whatsoever, in another closely allied animal. The whalebone
whale, again, has horny "whalebone" plates in its mouth, and no teeth;
but the young foetal whale, before it is born, has teeth in its jaws;
they, however, are never used, and they never come to anything. But
other members of the group to which the whale belongs have
well-developed teeth in both jaws.
Upon any hypothesis of special creation, facts of this kind appear to me
to be entirely unaccountable and inexplicable, but they cease to be so
if you accept Mr. Darwin's hypothesis, and see reason for believing that
the whalebone whale and the whale with teeth in its mouth both sprang
from a whale that had teeth, and that the teeth of the foetal whale
are merely remnants--recollections, if we may so say--of the extinct
whale. So in the case of the horse and the rhinoceros: suppose that both
have descended by modification from some earlier form which had the
normal number of toes, and the persistence of the rudimentary bones
which no longer support toes in the horse becomes comprehensible.
In the language that we speak in England, and in the language of the
Greeks, there are identical verbal roots, or elements entering into the
composition of words. That fact remains unintelligible so long as we
suppose English and Greek to be independently created tongues; but when
it is shown that both languages are descended from one original, the
Sanscrit, we give an explanation of that resemblance. In the same way
the existence of identical structural roots, if I may so term them,
entering into the composition of widely different animals, is striking
evidence in favour of the descent of those animals from a common
original.
To turn to another kind of illustration:--If you regard the whole series
of stratified rocks--that enormous thickness of sixty or seventy
thousand feet that I have mentioned before, constituting the only record
we have of a most prodigious lapse of time, that time being, in all
probability, but a fraction of that of which we have no record;--if you
observe in these successive strata of rocks successive groups of animals
arising and dying out, a constant succession, giving you the same kind
of impression, as you travel from one group of strata to another, as you
would have in travelling from one country to another;--when you find
this constant succession of forms, their traces obliterated except to
the man of science,--when you look at this wonderful history, and ask
what it means, it is only a paltering with words if you are offered the
reply,--"They were so created."
But if, on the other hand, you look on all forms of organized beings as
the results of the gradual modification of a primitive type, the facts
receive a meaning, and you see that these older conditions are the
necessary predecessors of the present. Viewed in this light the facts of
palæontology receive a meaning--upon any other hypothesis, I am unable
to see, in the slightest degree, what knowledge or signification we are
to draw out of them. Again, note as bearing upon the same point, the
singular likeness which obtains between the successive Faunæ and Floræ,
whose remains are preserved on the rocks: you never find any great and
enormous difference between the immediately successive Faunæ and Floræ,
unless you have reason to believe there has also been a great lapse of
time or a great change of conditions. The animals, for instance, of the
newest tertiary rocks, in any part of the world, are always, and without
exception, found to be closely allied with those which now live in that
part of the world. For example, in Europe, Asia, and Africa, the large
mammals are at present rhinoceri, hippopotami, elephants, lions, tigers,
oxen, horses, &c.; and if you examine the newest tertiary deposits,
which contain the animals and plants which immediately preceded those
which now exist in the same country, you do not find gigantic specimens
of ant-eaters and kangaroos, but you find rhinoceroses, elephants,
lions, tigers, &c.,--of different species to those now living,--but
still their close allies. If you turn to South America, where, at the
present day, we have great sloths and armadilloes and creatures of that
kind, what do you find in the newest tertiaries? You find the great
sloth-like creature, the _Megatherium_, and the great armadillo, the
_Glyptodon_, and so on. And if you go to Australia you find the same law
holds good, namely, that that condition of organic nature which has
preceded the one which now exists, presents differences perhaps of
species, and of genera, but that the great types of organic structure
are the same as those which now flourish.
What meaning has this fact upon any other hypothesis or supposition than
one of successive modification? But if the population of the world, in
any age, is the result of the gradual modification of the forms which
peopled it in the preceding age,--if that has been the case, it is
intelligible enough; because we may expect that the creature that
results from the modification of an elephantine mammal shall be
something like an elephant, and the creature which is produced by the
modification of an armadillo-like mammal shall be like an armadillo.
Upon that supposition, I say, the facts are intelligible; upon any
other, that I am aware of, they are not.
So far, the facts of palæontology are consistent with almost any form of
the doctrine of progressive modification; they would not be absolutely
inconsistent with the wild speculations of De Maillet, or with the less
objectionable hypothesis of Lamarck. But Mr. Darwin's views have one
peculiar merit; and that is, that they are perfectly consistent with an
array of facts which are utterly inconsistent with and fatal to, any
other hypothesis of progressive modification which has yet been
advanced. It is one remarkable peculiarity of Mr. Darwin's hypothesis
that it involves no necessary progression or incessant modification, and
that it is perfectly consistent with the persistence for any length of
time of a given primitive stock, contemporaneously with its
modifications. To return to the case of the domestic breeds of pigeons,
for example; you have the Dove-cot pigeon, which closely resembles the
Rock-pigeon, from which they all started, existing at the same time with
the others. And if species are developed in the same way in nature, a
primitive stock and its modifications may, occasionally, all find the
conditions fitted for their existence; and though they come into
competition, to a certain extent, with one another, the derivative
species may not necessarily extirpate the primitive one, or _vice
versâ_.
Now palæontology shows us many facts which are perfectly harmonious with
these observed effects of the process by which Mr. Darwin supposes
species to have originated, but which appear to me to be totally
inconsistent with any other hypothesis which has been proposed. There
are some groups of animals and plants, in the fossil world, which have
been said to belong to "persistent types," because they have persisted,
with very little change indeed, through a very great range of time,
while everything about them has changed largely. There are families of
fishes whose type of construction has persisted all the way from the
carboniferous rock right up to the cretaceous; and others which have
lasted through almost the whole range of the secondary rocks, and from
the lias to the older tertiaries. It is something stupendous this--to
consider a genus lasting without essential modifications through all
this enormous lapse of time while almost everything else was changed and
modified.
Thus I have no doubt that Mr. Darwin's hypothesis will be found
competent to explain the majority of the phenomena exhibited by species
in nature; but in an earlier lecture I spoke cautiously with respect to
its power of explaining all the physiological peculiarities of species.
There is, in fact, one set of these peculiarities which the theory of
selective modification, as it stands at present, is not wholly competent
to explain, and that is the group of phenomena which I mentioned to you
under the name of Hybridism, and which I explained to consist in the
sterility of the offspring of certain species when crossed one with
another. It matters not one whit whether this sterility is universal, or
whether it exists only in a single case. Every hypothesis is bound to
explain, or, at any rate, not be inconsistent with, the whole of the
facts which it professes to account for; and if there is a single one of
these facts which can be shown to be inconsistent with (I do not merely
mean inexplicable by, but contrary to,) the hypothesis, the hypothesis
falls to the ground,--it is worth nothing. One fact with which it is
positively inconsistent is worth as much, and as powerful in negativing
the hypothesis, as five hundred. If I am right in thus defining the
obligations of an hypothesis, Mr. Darwin, in order to place his views
beyond the reach of all possible assault, ought to be able to
demonstrate the possibility of developing from a particular stock by
selective breeding, two forms, which should either be unable to cross
one with another, or whose cross-bred offspring should be infertile with
one another.
For, you see, if you have not done that you have not strictly fulfilled
all the conditions of the problem; you have not shown that you can
produce, by the cause assumed, all the phenomena which you have in
nature. Here are the phenomena of Hybridism staring you in the face, and
you cannot say, "I can, by selective modification, produce these same
results." Now, it is admitted on all hands that, at present, so far as
experiments have gone, it has not been found possible to produce this
complete physiological divergence by selective breeding. I stated this
very clearly before, and I now refer to the point, because, if it could
be proved, not only that this _has_ not been done, but that it _cannot_
be done; if it could be demonstrated that it is impossible to breed
selectively, from any stock, a form which shall not breed with another,
produced from the same stock; and if we were shown that this must be the
necessary and inevitable result of all experiments, I hold that Mr.
Darwin's hypothesis would be utterly shattered.
But has this been done? or what is really the state of the case? It is
simply that, so far as we have gone yet with our breeding, we have not
produced from a common stock two breeds which are not more or less
fertile with one another.
I do not know that there is a single fact which would justify any one in
saying that any degree of sterility has been observed between breeds
absolutely known to have been produced by selective breeding from a
common stock. On the other hand, I do not know that there is a single
fact which can justify any one in asserting that such sterility cannot
be produced by proper experimentation. For my own part, I see every
reason to believe that it may, and will be so produced. For, as Mr.
Darwin has very properly urged, when we consider the phenomena of
sterility, we find they are most capricious; we do not know what it is
that the sterility depends on. There are some animals which will not
breed in captivity; whether it arises from the simple fact of their
being shut up and deprived of their liberty, or not, we do not know, but
they certainly will not breed. What an astounding thing this is, to find
one of the most important of all functions annihilated by mere
imprisonment!
So, again, there are cases known of animals which have been thought by
naturalists to be undoubted species, which have yielded perfectly
fertile hybrids; while there are other species which present what
everybody believes to be varieties[55] which are more or less infertile
with one another. There are other cases which are truly extraordinary;
there is one, for example, which has been carefully examined,--of two
kinds of sea-weed, of which the male element of the one, which we may
call A, fertilizes the female element of the other, B; while the male
element of B will not fertilize the female element of A; so that, while
the former experiment seems to show us that they are _varieties_, the
latter leads to the conviction that they are _species_.
When we see how capricious and uncertain this sterility is, how unknown
the conditions on which it depends, I say that we have no right to
affirm that those conditions will not be better understood by and by,
and we have no ground for supposing that we may not be able to
experiment so as to obtain that crucial result which I mentioned just
now. So that though Mr. Darwin's hypothesis does not completely
extricate us from this difficulty at present, we have not the least
right to say it will not do so.
There is a wide gulf between the thing you cannot explain and the thing
that upsets you altogether. There is hardly any hypothesis in this world
which has not some fact in connection with it which has not been
explained, but that is a very different affair to a fact that entirely
opposes your hypothesis; in this case all you can say is, that your
hypothesis is in the same position as a good many others.
Now, as to the third test, that there are no other causes competent to
explain the phenomena, I explained to you that one should be able to say
of an hypothesis, that no other known causes than those supposed by it
are competent to give rise to the phenomena. Here, I think, Mr. Darwin's
view is pretty strong. I really believe that the alternative is either
Darwinism or nothing, for I do not know of any rational conception or
theory of the organic universe which has any scientific position at all
beside Mr. Darwin's. I do not know of any proposition that has been put
before us with the intention of explaining the phenomena of organic
nature, which has in its favour a thousandth part of the evidence which
may be adduced in favour of Mr. Darwin's views. Whatever may be the
objections to his views, certainly all other theories are absolutely out
of court.
Take the Lamarckian hypothesis, for example. Lamarck was a great
naturalist, and to a certain extent went the right way to work; he
argued from what was undoubtedly a true cause of some of the phenomena
of organic nature. He said it is a matter of experience that an animal
may be modified more or less in consequence of its desires and
consequent actions. Thus, if a man exercise himself as a blacksmith, his
arms will become strong and muscular; such organic modification is a
result of this particular action and exercise. Lamarck thought that by a
very simple supposition based on this truth he could explain the origin
of the various animal species: he said, for example, that the
short-legged birds which live on fish, had been converted into the
long-legged waders by desiring to get the fish without wetting their
feathers, and so stretching their legs more and more through successive
generations. If Lamarck could have shown experimentally, that even races
of animals could be produced in this way, there might have been some
ground for his speculations. But he could show nothing of the kind, and
his hypothesis has pretty well dropped into oblivion, as it deserved to
do. I said in an earlier lecture that there are hypotheses and
hypotheses, and when people tell you that Mr. Darwin's strongly-based
hypothesis is nothing but a mere modification of Lamarck's, you will
know what to think of their capacity for forming a judgment on this
subject.
But you must recollect that when I say I think it is either Mr. Darwin's
hypothesis or nothing; that either we must take his view, or look upon
the whole of organic nature as an enigma, the meaning of which is wholly
hidden from us; you must understand that I mean that I accept it
provisionally, in exactly the same way as I accept any other hypothesis.
Men of science do not pledge themselves to creeds; they are bound by
articles of no sort; there is not a single belief that it is not a
bounden duty with them to hold with a light hand and to part with it,
cheerfully, the moment it is really proved to be contrary to any fact,
great or small. And if in course of time I see good reasons for such a
proceeding, I shall have no hesitation in coming before you, and
pointing out any change in my opinion without finding the slightest
occasion to blush for so doing. So I say that we accept this view as we
accept any other, so long as it will help us, and we feel bound to
retain it only so long as it will serve our great purpose--the
improvement of Man's estate and the widening of his knowledge. The
moment this, or any other conception, ceases to be useful for these
purposes, away with it to the four winds; we care not what becomes of
it!
But to say truth, although it has been my business to attend closely to
the controversies roused by the publication of Mr. Darwin's book, I
think that not one of the enormous mass of objections and obstacles
which have been raised is of any very great value, except that sterility
case which I brought before you just now. All the rest are
misunderstandings of some sort, arising either from prejudice, or want
of knowledge, or still more from want of patience and care in reading
the work.
For you must recollect that it is not a book to be read, with as much
ease, as its pleasant style may lead you to imagine. You spin through it
as if it were a novel the first time you read it, and think you know all
about it; the second time you read it you think you know rather less
about it; and the third time, you are amazed to find how little you have
really apprehended its vast scope and objects. I can positively say that
I never take it up without finding in it some new view, or light, or
suggestion that I have not noticed before. That is the best
characteristic of a thorough and profound book; and I believe this
feature of the "Origin of Species" explains why so many persons have
ventured to pass judgment and criticisms upon it which are by no means
worth the paper they are written on.
Before concluding these lectures there is one point to which I must
advert,--though, as Mr. Darwin has said nothing about man in his book,
it concerns myself rather than him;--for I have strongly maintained on
sundry occasions that if Mr. Darwin's views are sound, they apply as
much to man as to the lower mammals, seeing that it is perfectly
demonstrable that the structural differences which separate man from the
apes are not greater than those which separate some apes from others.
There cannot be the slightest doubt in the world that the argument which
applies to the improvement of the horse from an earlier stock, or of ape
from ape, applies to the improvement of man from some simpler and lower
stock than man. There is not a single faculty--functional or structural,
moral, intellectual, or instinctive,--there is no faculty whatever that
is not capable of improvement; there is no faculty whatsoever which does
not depend upon structure, and as structure tends to vary, it is capable
of being improved.
Well, I have taken a good deal of pains at various times to prove this,
and I have endeavoured to meet the objections of those who maintain,
that the structural differences between man and the lower animals are of
so vast a character and enormous extent, that even if Mr. Darwin's views
are correct, you cannot imagine this particular modification to take
place. It is, in fact, easy matter to prove that, so far as structure is
concerned, man differs to no greater extent from the animals which are
immediately below him than these do from other members of the same
order. Upon the other hand, there is no one who estimates more highly
than I do the dignity of human nature, and the width of the gulf in
intellectual and moral matters, which lies between man and the whole of
the lower creation.
But I find this very argument brought forward vehemently by some. "You
say that man has proceeded from a modification of some lower animal, and
you take pains to prove that the structural differences which are said
to exist in his brain do not exist at all, and you teach that all
functions, intellectual, moral, and others, are the expression or the
result, in the long run, of structures, and of the molecular forces
which they exert." It is quite true that I do so.
"Well, but," I am told at once, somewhat triumphantly, "you say in the
same breath that there is a great moral and intellectual chasm between
man and the lower animals. How is this possible when you declare that
moral and intellectual characteristics depend on structure, and yet tell
us that there is no such gulf between the structure of man and that of
the lower animals?"
I think that objection is based upon a misconception of the real
relations which exist between structure and function, between mechanism
and work. Function is the expression of molecular forces and
arrangements no doubt; but, does it follow from this, that variation in
function so depends upon variation in structure that the former is
always exactly proportioned to the latter? If there is no such relation,
if the variation in function which follows on a variation in structure,
may be enormously greater than the variation of the structure, then, you
see, the objection falls to the ground.
Take a couple of watches--made by the same maker, and as completely
alike as possible; set them upon the table, and the function of
each--which is its rate of going--will be performed in the same manner,
and you shall be able to distinguish no difference between them; but let
me take a pair of pincers, and if my hand is steady enough to do it, let
me just lightly crush together the bearings of the balance-wheel, or
force to a slightly different angle the teeth of the escapement of one
of them, and of course you know the immediate result will be that the
watch, so treated, from that moment will cease to go. But what
proportion is there between the structural alteration and the functional
result? Is it not perfectly obvious that the alteration is of the
minutest kind, yet that slight as it is, it has produced an infinite
difference in the performance of the functions of these two
instruments?
Well, now, apply that to the present question. What is it that
constitutes and makes man what he is? What is it but his power of
language--that language giving him the means of recording his
experience--making every generation somewhat wiser than its
predecessor,--more in accordance with the established order of the
universe?
What is it but this power of speech, of recording experience, which
enables men to be men--looking before and after and, in some dim sense,
understanding the working of this wondrous universe--and which
distinguishes man from the whole of the brute world? I say that this
functional difference is vast, unfathomable, and truly infinite in its
consequences; and I say at the same time, that it may depend upon
structural differences which shall be absolutely inappreciable to us
with our present means of investigation. What is this very speech that
we are talking about? I am speaking to you at this moment, but if you
were to alter, in the minutest degree, the proportion of the nervous
forces now active in the two nerves which supply the muscles of my
glottis, I should become suddenly dumb. The voice is produced only so
long as the vocal chords are parallel; and these are parallel only so
long as certain muscles contract with exact equality; and that again
depends on the equality of action of those two nerves I spoke of. So
that a change of the minutest kind in the structure of one of these
nerves, or in the structure of the part in which it originates, or of
the supply of blood to that part, or of one of the muscles to which it
is distributed, might render all of us dumb. But a race of dumb men,
deprived of all communication with those who could speak, would be
little indeed removed from the brutes. And the moral and intellectual
difference between them and ourselves would be practically infinite,
though the naturalist should not be able to find a single shadow of even
specific structural difference.
But let me dismiss this question now, and, in conclusion, let me say
that you may go away with it as my mature conviction, that Mr. Darwin's
work is the greatest contribution which has been made to biological
science since the publication of the "Règne Animal" of Cuvier, and
since that of the "History of Development," of Von Baer. I believe that
if you strip it of its theoretical part it still remains one of the
greatest encyclopædias of biological doctrine that any one man ever
brought forth; and I believe that, if you take it as the embodiment of
an hypothesis, it is destined to be the guide of biological and
psychological speculation for the next three or four generations.
FOOTNOTES:
[55] And as I conceive with very good reason; but if any objector urges
that we cannot prove that they have been produced by artificial or
natural selection, the objection must be admitted--ultra-sceptical as it
is. But in science, scepticism is a duty.
X
ON THE EDUCATIONAL VALUE OF THE
NATURAL HISTORY SCIENCES.
The subject to which I have to beg your attention during the ensuing
hour is "The Relation of Physiological Science to other branches of
knowledge."
Had circumstances permitted of the delivery, in their strict logical
order, of that series of discourses of which the present lecture is a
member, I should have preceded my friend and colleague Mr. Henfrey, who
addressed you on Monday last; but while, for the sake of that order, I
must beg you to suppose that this discussion of the Educational bearings
of Biology in general _does_ precede that of Special Zoology and Botany,
I am rejoiced to be able to take advantage of the light thus already
thrown upon the tendency and methods of Physiological Science.
Regarding Physiological Science then, in its widest sense--as the
equivalent of _Biology_--the Science of Individual Life--we have to
consider in succession:
1. Its position and scope as a branch of knowledge.
2. Its value as a means of mental discipline.
3. Its worth as practical information.
And lastly,
4. At what period it may best be made a branch of Education.
Our conclusions on the first of these heads must depend, of course, upon
the nature of the subject-matter of Biology; and I think a few
preliminary considerations will place before you in a clear light the
vast difference which exists between the living bodies with which
Physiological science is concerned, and the remainder of the
universe;--between the phænomena of Number and Space, of Physical and of
Chemical force, on the one hand, and those of Life on the other.
The mathematician, the physicist, and the chemist contemplate things in
a condition of rest; they look upon a state of equilibrium as that to
which all bodies normally tend.
The mathematician does not suppose that a quantity will alter, or that a
given point in space will change its direction with regard to another
point, spontaneously. And it is the same with the physicist. When Newton
saw the apple fall, he concluded at once that the act of falling was not
the result of any power inherent in the apple, but that it was the
result of the action of something else on the apple. In a similar
manner, all physical force is regarded as the disturbance of an
equilibrium to which things tended before its exertion,--to which they
will tend again after its cessation.
The chemist equally regards chemical change in a body, as the effect of
the action of something external to the body changed. A chemical
compound once formed would persist for ever, if no alteration took place
in surrounding conditions.
But to the student of Life the aspect of nature is reversed. Here,
incessant, and, so far as we know, spontaneous change is the rule, rest
the exception--the anomaly to be accounted for. Living things have no
inertia and tend to no equilibrium.
Permit me, however, to give more force and clearness to these somewhat
abstract considerations, by an illustration or two.
Imagine a vessel full of water, at the ordinary temperature, in an
atmosphere saturated with vapour. The _quantity_ and the _figure_ of
that water will not change, so far as we know, for ever.
Suppose a lump of gold be thrown into the vessel--motion and disturbance
of figure exactly proportional to the momentum of the gold will take
place. But after a time the effects of this disturbance will
subside--equilibrium will be restored, and the water will return to its
passive state.
Expose the water to cold--it will solidify--and in so doing its
particles will arrange themselves in definite crystalline shapes. But
once formed, these crystals change no further.
Again, substitute for the lump of gold some substance capable of
entering into chemical relations with the water:--say, a mass of that
substance which is called "protein"--the substance of flesh:--a very
considerable disturbance of equilibrium will take place--all sorts of
chemical compositions and decompositions will occur; but in the end, as
before, the result will be the resumption of a condition of rest.
Instead of such a mass of _dead_ protein, however, take a particle of
_living_ protein--one of those minute microscopic living things which
throng our pools, and are known as Infusoria--such a creature, for
instance, as an Euglena, and place it in our vessel of water. It is a
round mass provided with a long filament, and except in this peculiarity
of shape, presents no appreciable physical or chemical difference
whereby it might be distinguished from the particle of dead protein.
But the difference in the phænomena to which it will give rise is
immense: in the first place it will develope a vast quantity of physical
force--cleaving the water in all directions, with considerable rapidity,
by means of the vibrations of the long filament or cilium.
Nor is the amount of chemical energy which the little creature possesses
less striking. It is a perfect laboratory in itself, and it will act and
react upon the water and the matters contained therein; converting them
into new compounds resembling its own substance and, at the same time,
giving up portions of its own substance which have become effete.
Furthermore, the Euglena will increase in size; but this increase is by
no means unlimited, as the increase of a crystal might be. After it has
grown to a certain extent it divides, and each portion assumes the form
of the original and proceeds to repeat the process of growth and
division.
Nor is this all. For after a series of such divisions and subdivisions,
these minute points assume a totally new form, lose their long
tails--round themselves, and secrete a sort of envelope or box, in which
they remain shut up for a time, eventually to resume, directly or
indirectly, their primitive mode of existence.
Now, so far as we know, there is no natural limit to the existence of
the Euglena, or of any other living germ. A living species once launched
into existence tends to live for ever.
Consider how widely different this living particle is from the dead
atoms with which the physicist and chemist have to do!
The particle of gold falls to the bottom and rests--the particle of dead
protein decomposes and disappears--it also rests: but the _living_
protein mass neither tends to exhaustion of its forces nor to any
permanency of form, but is essentially distinguished as a disturber of
equilibrium so far as force is concerned,--as undergoing continual
metamorphosis and change, in point of form.
Tendency to equilibrium of force, and to permanency of form then, are
the characters of that portion of the universe which does not live--the
domain of the chemist and physicist.
Tendency to disturb existing equilibrium,--to take on forms which
succeed one another in definite cycles, is the character of the living
world.
What is the cause of this wonderful difference between the dead particle
and the living particle of matter appearing in other respects identical?
that difference to which we give the name of Life?
I, for one, cannot tell you. It may be that, by and bye, philosophers
will discover some higher laws of which the facts of life are particular
cases--very possibly they will find out some bond between
physico-chemical phænomena on the one hand, and vital phænomena on the
other. At present, however, we assuredly know of none; and I think we
shall exercise a wise humility in confessing that, for us at least, this
successive assumption of different states--(external conditions
remaining the same)--this _spontaneity of action_--if I may use a term
which implies more than I would be answerable for--which constitutes so
vast and plain a practical distinction between living bodies and those
which do not live, is an ultimate fact; indicating as such, the
existence of a broad line of demarcation between the subject-matter of
Biological and that of all other sciences.
For I would have it understood that this simple Euglena is the type of
_all_ living things, so far as the distinction between these and inert
matter is concerned. That cycle of changes, which is constituted by
perhaps not more than two or three steps in the Euglena, is as clearly
manifested in the multitudinous stages through which the germ of an oak
or of a man passes. Whatever forms the Living Being may take on, whether
simple or complex,--_production_, _growth_, _reproduction_,--are the
phænomena which distinguish it from that which does not live.
If this be true, it is clear that the student, in passing from the
physico-chemical to the physiological sciences, enters upon a totally
new order of facts; and it will next be for us to consider how far these
new facts involve _new_ methods, or require a modification of those with
which he is already acquainted. Now a great deal is said about the
peculiarity of the scientific method in general, and of the different
methods which are pursued in the different sciences. The Mathematics are
said to have one special method; Physics another, Biology a third, and
so forth. For my own part, I must confess that I do not understand this
phraseology. So far as I can arrive at any clear comprehension of the
matter, Science is not, as many would seem to suppose, a modification of
the black art, suited to the tastes of the nineteenth century, and
flourishing mainly in consequence of the decay of the Inquisition.
Science is, I believe, nothing but _trained and organized common sense_,
differing from the latter only as a veteran may differ from a raw
recruit: and its methods differ from those of common sense only so far
as the guardsman's cut and thrust differ from the manner in which a
savage wields his club. The primary power is the same in each case, and
perhaps the untutored savage has the more brawny arm of the two. The
_real_ advantage lies in the point and polish of the swordsman's weapon;
in the trained eye quick to spy out the weakness of the adversary; in
the ready hand prompt to follow it on the instant. But after all, the
sword exercise is only the hewing and poking of the clubman developed
and perfected.
So, the vast results obtained by Science are won by no mystical
faculties, by no mental processes, other than those which are practised
by every one of us, in the humblest and meanest affairs of life. A
detective policeman discovers a burglar from the marks made by his shoe,
by a mental process identical with that by which Cuvier restored the
extinct animals of Montmartre from fragments of their bones. Nor does
that process of induction and deduction by which a lady, finding a stain
of a peculiar kind upon her dress, concludes that somebody has upset the
inkstand thereon, differ in any way, in kind, from that by which Adams
and Leverrier discovered a new planet.
The man of science, in fact, simply uses with scrupulous exactness, the
methods which we all, habitually and at every moment, use carelessly;
and the man of business must as much avail himself of the scientific
method--must be as truly a man of science--as the veriest book-worm of
us all; though I have no doubt that the man of business will find
himself out to be a philosopher with as much surprise as M. Jourdain
exhibited when he discovered that he had been all his life talking
prose. If, however, there be no real difference between the methods of
science and those of common life, it would seem on the face of the
matter highly improbable that there should be any difference between the
methods of the different sciences; nevertheless, it is constantly taken
for granted, that there is a very wide difference between the
Physiological and other sciences in point of method.
In the first place it is said--and I take this point first, because the
imputation is too frequently admitted by Physiologists themselves--that
Biology differs from the Physico-chemical and Mathematical sciences, in
being "inexact."
Now, this phrase "inexact" must refer either to the _methods_ or to the
_results_ of Physiological science.
It cannot be correct to apply it to the methods; for, as I hope to show
you by and bye, these are identical in all sciences, and whatever is
true of Physiological method is true of Physical and Mathematical
method.
Is it then the _results_ of Biological science which are "inexact"? I
think not. If I say that respiration is performed by the lungs; that
digestion is effected in the stomach; that the eye is the organ of
sight; that the jaws of a vertebrated animal never open sideways, but
always up and down; while those of an annulose animal always open
sideways, and never up and down--I am enumerating propositions which are
as exact as anything in Euclid. How then has this notion of the
inexactness of Biological science come about? I believe from two causes:
first, because, in consequence of the great complexity of the science
and the multitude of interfering conditions, we are very often only
enabled to predict approximately what will occur under given
circumstances; and secondly, because, on account of the comparative
youth of the Physiological sciences, a great many of their laws are
still imperfectly worked out. But in an educational point of view, it is
most important to distinguish between the essence of a science and the
accidents which surround it; and essentially, the methods and results of
Physiology are as exact as those of Physics or Mathematics.
It is said that the Physiological method is especially
_comparative_[56]; and this dictum also finds favour in the eyes of
many. I should be sorry to suggest that the speculators on scientific
classification have been misled by the accident of the name of one
leading branch of Biology--_Comparative Anatomy_; but I would ask
whether _comparison_, and that classification which is the result of
comparison, are not the essence of every science whatsoever? How is it
possible to discover a relation of cause and effect of _any_ kind
without comparing a series of cases together in which the supposed cause
and effect occur singly, or combined? So far from comparison being in
any way peculiar to Biological science, it is, I think, the essence of
every science.
A speculative philosopher again tells us that the Biological sciences
are distinguished by being sciences of observation and not of
experiment![57]
Of all the strange assertions into which speculation without practical
acquaintance with a subject may lead even an able man, I think this is
the very strangest. Physiology not an experimental science! Why, there
is not a function of a single organ in the body which has not been
determined wholly and solely by experiment? How did Harvey determine the
nature of the circulation, except by experiment? How did Sir Charles
Bell determine the functions of the roots of the spinal nerves, save by
experiment? How do we know the use of a nerve at all, except by
experiment? Nay, how do you know even that your eye is your seeing
apparatus, unless you make the experiment of shutting it; or that your
ear is your hearing apparatus, unless you close it up and thereby
discover that you become deaf?
It would really be much more true to say that Physiology is _the_
experimental science _par excellence_ of all sciences; that in which
there is least to be learnt by mere observation, and that which affords
the greatest field for the exercise of those faculties which
characterize the experimental philosopher. I confess, if any one were to
ask me for a model application of the logic of experiment, I should know
no better work to put into his hands than Bernard's late Researches on
the Functions of the Liver.[58]
Not to give this lecture a too controversial tone however, I must only
advert to one more doctrine, held by a thinker of our own age and
country, whose opinions are worthy of all respect. It is, that the
Biological sciences differ from all others, inasmuch as in _them_,
classification takes place by type and not by definition.[59]
It is said, in short, that a natural-history class is not capable of
being defined--that the class Rosaceæ, for instance, or the class of
Fishes, is not accurately and absolutely definable, inasmuch as its
members will present exceptions to every possible definition; and that
the members of the class are united together only by the circumstance
that they are all more like some imaginary average rose or average fish,
than they resemble anything else.
But here, as before, I think the distinction has arisen entirely from
confusing a transitory imperfection with an essential character. So long
as our information concerning them is imperfect, we class all objects
together according to resemblances which we _feel_, but cannot _define_:
we group them round _types_, in short. Thus, if you ask an ordinary
person what kinds of animals there are, he will probably say, beasts,
birds, reptiles, fishes, insects, &c. Ask him to define a beast from a
reptile, and he cannot do it; but he says, things like a cow or a horse
are beasts, and things like a frog or a lizard are reptiles. You see _he
does_ class by type, and not by definition. But how does this
classification differ from that of the scientific Zoologist? How does
the meaning of the scientific class-name of "Mammalia" differ from the
unscientific of "Beasts"?
Why, exactly because the former depends on a definition, the latter on a
type. The class Mammalia is scientifically defined as "all animals which
have a vertebrated skeleton and suckle their young." Here is no
reference to type, but a definition rigorous enough for a geometrician.
And such is the character which every scientific naturalist recognizes
as that to which his classes must aspire--knowing, as he does, that
classification by type is simply an acknowledgment of ignorance and a
temporary device.
So much in the way of negative argument as against the reputed
differences between Biological and other methods. No such differences, I
believe, really exist. The subject-matter of Biological science is
different from that of other sciences, but the methods of all are
identical; and these methods are--
1. _Observation_ of facts--including under this head that _artificial
observation_ which is called _experiment_.
2. That process of tying up similar facts into bundles, ticketed and
ready for use, which is called _Comparison_ and _Classification_,--the
results of the process, the ticketed bundles, being named _General
propositions_.
3. _Deduction_, which takes us from the general proposition to facts
again--teaches us, if I may so say, to anticipate from the ticket what
is inside the bundle. And finally--
4. _Verification_, which is the process of ascertaining whether, in
point of fact, our anticipation is a correct one.
Such are the methods of all science whatsoever; but perhaps you will
permit me to give you an illustration of their employment in the science
of Life; and I will take as a special case, the establishment of the
doctrine of the _Circulation of the Blood_.
In this case, _simple observation_ yields us a knowledge of the
existence of the blood from some accidental hæmorrhage, we will say: we
may even grant that it informs us of the localisation of this blood in
particular vessels, the heart, &c., from some accidental cut or the
like. It teaches also the existence of a pulse in various parts of the
body, and acquaints us with the structure of the heart and vessels.
Here, however, _simple observation_ stops, and we must have recourse to
_experiment_.
You tie a vein, and you find that the blood accumulates on the side of
the ligature opposite the heart. You tie an artery, and you find that
the blood accumulates on the side near the heart. Open the chest, and
you see the heart contracting with great force. Make openings into its
principal cavities, and you will find that all the blood flows out, and
no more pressure is exerted on either side of the arterial or venous
ligature.
Now all these facts, taken together, constitute the evidence that the
blood is propelled by the heart through the arteries, and returns by the
veins--that, in short, the blood circulates.
Suppose our experiments and observations have been made on horses, then
we group and ticket them into a general proposition, thus:--_all horses
have a circulation of their blood_.
Henceforward a horse is a sort of indication or label, telling us where
we shall find a peculiar series of phænomena called the circulation of
the blood.
Here is our _general proposition_ then.
How and when are we justified in making our next step--a _deduction_
from it?
Suppose our physiologist, whose experience is limited to horses, meets
with a zebra for the first time,--will he suppose that his
generalization holds good for zebras also?
That depends very much on his turn of mind. But we will suppose him to
be a bold man. He will say, "The zebra is certainly not a horse, but it
is very like one,--so like, that it must be the 'ticket' or mark of a
blood-circulation also; and, I conclude that the zebra has a
circulation."
That is a deduction, a very fair deduction, but by no means to be
considered scientifically secure. This last quality in fact can only be
given by _verification_--that is, by making a zebra the subject of all
the experiments performed on the horse. Of course in the present case
the _deduction_ would be _confirmed_ by this process of verification,
and the result would be, not merely a positive widening of knowledge,
but a fair increase of confidence in the truth of one's generalizations
in other cases.
Thus, having settled the point in the zebra and horse, our philosopher
would have great confidence in the existence of a circulation in the
ass. Nay, I fancy most persons would excuse him, if in this case he did
not take the trouble to go through the process of verification at all;
and it would not be without a parallel in the history of the human mind,
if our imaginary physiologist now maintained that he was acquainted with
asinine circulation _à priori_.
However, if I might impress any caution upon your minds, it is, the
utterly conditional nature of all our knowledge,--the danger of
neglecting the process of verification under any circumstances; and the
film upon which we rest, the moment our deductions carry us beyond the
reach of this great process of verification. There is no better instance
of this than is afforded by the history of our knowledge of the
circulation of the blood in the animal kingdom until the year 1824. In
every animal possessing a circulation at all, which had been observed up
to that time, the current of the blood was known to take one definite
and invariable direction. Now, there is a class of animals called
_Ascidians_, which possess a heart and a circulation, and up to the
period of which I speak, no one would have dreamt of questioning the
propriety of the deduction, that these creatures have a circulation in
one direction; nor would any one have thought it worth while to verify
the point. But, in that year, M. von Hasselt happening to examine a
transparent animal of this class, found to his infinite surprise, that
after the heart had beat a certain number of times, it stopped, and then
began beating the opposite way--so as to reverse the course of the
current, which returned by and bye to its original direction.
I have myself timed the heart of these little animals. I found it as
regular as possible in its periods of reversal: and I know no spectacle
in the animal kingdom more wonderful than that which it presents--all
the more wonderful that to this day it remains an unique fact, peculiar
to this class among the whole animated world. At the same time I know of
no more striking case of the necessity of the _verification_ of even
those deductions which seem founded on the widest and safest inductions.
Such are the methods of Biology--methods which are obviously identical
with those of all other sciences, and therefore wholly incompetent to
form the ground of any distinction between it and them.[60]
But I shall be asked at once, do you mean to say that there is no
difference between the habit of mind of a mathematician and that of a
naturalist? Do you imagine that Laplace might have been put into the
Jardin des Plantes, and Cuvier into the Observatory, with equal
advantage to the progress of the sciences they professed?
To which I would reply, that nothing could be further from my thoughts.
But different habits and various special tendencies of two sciences do
not imply different methods. The mountaineer and the man of the plains
have very different habits of progression, and each would be at a loss
in the other's place; but the method of progression, by putting one leg
before the other, is the same in each case. Every step of each is a
combination of a lift and a push; but the mountaineer lifts more and the
lowlander pushes more. And I think the case of two sciences resembles
this.
I do not question for a moment, that while the Mathematician is busy
with deductions _from_ general propositions, the Biologist is more
especially occupied with observation, comparison, and those processes
which lead _to_ general propositions. All I wish to insist upon is,
that this difference depends not on any fundamental distinction in the
sciences themselves, but on the accidents of their subject-matter, of
their relative complexity, and consequent relative perfection.
The Mathematician deals with two properties of objects only, number and
extension, and all the inductions he wants have been formed and finished
ages ago. He is occupied now with nothing but deduction and
verification.
The biologist deals with a vast number of properties of objects, and his
inductions will not be completed, I fear, for ages to come; but when
they are, his science will be as deductive and as exact as the
Mathematics themselves.
Such is the relation of Biology to those sciences which deal with
objects having fewer properties than itself. But as the student in
reaching Biology looks back upon sciences of a less complex and
therefore more perfect nature, so on the other hand does he look forward
to other more complex and less perfect branches of knowledge. Biology
deals only with living beings as isolated things--treats only of the
life of the individual: but there is a higher division of science still,
which considers living beings as aggregates--which deals with the
relation of living beings one to another--the science which _observes_
men--whose _experiments_ are made by nations one upon another, in
battle-fields--whose _general propositions_ are embodied in history,
morality, and religion--whose _deductions_ lead to our happiness or our
misery,--and whose _verifications_ so often come too late, and serve
only
"To point a moral or adorn a tale"--
I mean the science of Society or _Sociology_.
I think it is one of the grandest features of Biology, that it occupies
this central position in human knowledge. There is no side of the human
mind which physiological study leaves uncultivated. Connected by
innumerable ties with abstract science, Physiology is yet in the most
intimate relation with humanity; and by teaching us that law and order,
and a definite scheme of development, regulate even the strangest and
wildest manifestations of individual life, she prepares the student to
look for a goal even amidst the erratic wanderings of mankind, and to
believe that history offers something more than an entertaining chaos--a
journal of a toilsome, tragi-comic march nowhither.
The preceding considerations have, I hope, served to indicate the
replies which befit the two first of the questions which I set before
you at starting, viz. what is the range and position of Physiological
Science as a branch of knowledge, and what is its value as a means of
mental discipline?
Its _subject-matter_ is a large moiety of the universe--its _position_
is midway between the physico-chemical and the social sciences. Its
_value_ as a branch of discipline is partly that which it has in common
with all sciences--the training and strengthening of common sense;
partly that which is more peculiar to itself--the great exercise which
it affords to the faculties of observation and comparison; and I may
add, the _exactness_ of knowledge which it requires on the part of those
among its votaries who desire to extend its boundaries.
If what has been said as to the position and scope of Biology be
correct, our third question--what is the practical value of
physiological instruction?--might, one would think, be left to answer
itself.
On other grounds even, were mankind deserving of the title "rational,"
which they arrogate to themselves, there can be no question that they
would consider as the most necessary of all branches of instruction for
themselves and for their children--that which professes to acquaint them
with the conditions of the existence they prize so highly--which teaches
them how to avoid disease and to cherish health, in themselves and those
who are dear to them.
I am addressing, I imagine, an audience of educated persons; and yet I
dare venture to assert, that with the exception of those of my hearers
who may chance to have received a medical education, there is not one
who could tell me what is the meaning and use of an act which he
performs a score of times every minute, and whose suspension would
involve his immediate death;--I mean the act of breathing--or who could
state in precise terms why it is that a confined atmosphere is injurious
to health.
The _Practical value_ of Physiological knowledge! Why is it that
educated men can be found to maintain that a slaughter-house in the
midst of a great city is rather a good thing than otherwise?--that
mothers persist in exposing the largest possible amount of surface of
their children to the cold, by the absurd style of dress they adopt, and
then marvel at the peculiar dispensation of Providence, which removes
their infants by bronchitis and gastric fever? Why is it that quackery
rides rampant over the land; and that not long ago, one of the largest
public rooms in this great city could be filled by an audience gravely
listening to the reverend expositor of the doctrine--that the simple
physiological phenomena known as spirit-rapping, table-turning,
phreno-magnetism, and by I know not what other absurd and inappropriate
names, are due to the direct and personal agency of Satan?
Why is all this, except from the utter ignorance as to the simplest laws
of their own animal life, which prevails among even the most highly
educated persons in this country?
But there are other branches of Biological Science, besides Physiology
proper, whose practical influence, though less obvious, is not, as I
believe, less certain. I have heard educated men speak with an
ill-disguised contempt of the studies of the naturalist, and ask, not
without a shrug, "What is the use of knowing all about these miserable
animals--what bearing has it on human life?"
I will endeavour to answer that question. I take it that all will admit
there is definite Government of this universe--that its pleasures and
pains are not scattered at random, but are distributed in accordance
with orderly and fixed laws, and that it is only in accordance with all
we know of the rest of the world, that there should be an agreement
between one portion of the sensitive creation and another in these
matters.
Surely then it interests us to know the lot of other animal
creatures--however far below us, they are still the sole created things
which share with us the capability of pleasure and the susceptibility to
pain.
I cannot but think that he who finds a certain proportion of pain and
evil inseparably woven up in the life of the very worms, will bear his
own share with more courage and submission; and will, at any rate, view
with suspicion those weakly amiable theories of the Divine government,
which would have us believe pain to be an oversight and a mistake,--to
be corrected by and bye. On the other hand, the predominance of
happiness among living things--their lavish beauty--the secret and
wonderful harmony which pervades them all, from the highest to the
lowest, are equally striking refutations of that modern Manichean
doctrine, which exhibits the world as a slave-mill, worked with many
tears, for mere utilitarian ends.
There is yet another way in which natural history may, I am convinced,
take a profound hold upon practical life,--and that is, by its influence
over our finer feelings, as the greatest of all sources of that pleasure
which is derivable from beauty. I do not pretend that natural-history
knowledge, as such, can increase our sense of the beautiful in natural
objects. I do not suppose that the dead soul of Peter Bell, of whom the
great poet of nature says,--
"A primrose by the river's brim,
A yellow primrose was to him,--
And it was nothing more,"--
would have been a whit roused from its apathy, by the information that
the primrose is a Dicotyledonous Exogen, with a monopetalous corolla and
central placentation. But I advocate natural-history knowledge from this
point of view, because it would lead us to _seek_ the beauties of
natural objects, instead of trusting to chance to force them on our
attention. To a person uninstructed in natural history, his country or
sea-side stroll is a walk through a gallery filled with wonderful works
of art, nine-tenths of which have their faces turned to the wall. Teach
him something of natural history, and you place in his hands a catalogue
of those which are worth turning round. Surely our innocent pleasures
are not so abundant in this life, that we can afford to despise this or
any other source of them. We should fear being banished for our neglect
to that limbo, where the great Florentine tells us are those who during
this life "wept when they might be joyful."
But I shall be trespassing unwarrantably on your kindness, if I do not
proceed at once to my last point--the time at which Physiological
Science should first form a part of the Curriculum of Education.
The distinction between the teaching of the facts of a science as
instruction, and the teaching it systematically as knowledge, has
already been placed before you in a previous lecture: and it appears to
me, that, as with other sciences, the _common facts_ of Biology--the
uses of parts of the body--the names and habits of the living creatures
which surround us--may be taught with advantage to the youngest child.
Indeed, the avidity of children for this kind of knowledge, and the
comparative ease with which they retain it, is something quite
marvellous. I doubt whether any toy would be so acceptable to young
children as a vivarium, of the same kind as, but of course on a smaller
scale than, those admirable devices in the Zoological Gardens.
On the other hand, systematic teaching in Biology cannot be attempted
with success until the student has attained to a certain knowledge of
physics and chemistry: for though the phænomena of life are dependent
neither on physical nor on chemical, but on vital forces, yet they
result in all sorts of physical and chemical changes, which can only be
judged by their own laws.
And now to sum up in a few words the conclusions to which I hope you see
reason to follow me.
Biology needs no apologist when she demands a place--and a prominent
place--in any scheme of education worthy of the name. Leave out the
Physiological sciences from your curriculum, and you launch the student
into the world, undisciplined in that science whose subject-matter would
best develope his powers of observation; ignorant of facts of the
deepest importance for his own and others' welfare; blind to the richest
sources of beauty in God's creation; and unprovided with that belief in
a living law, and an order manifesting itself in and through endless
change and variety, which might serve to check and moderate that phase
of despair through which, if he take an earnest interest in social
problems, he will assuredly sooner or later pass.
Finally, one word for myself. I have not hesitated to speak strongly
where I have felt strongly; and I am but too conscious that the
indicative and imperative moods have too often taken the place of the
more becoming subjunctive and conditional. I feel, therefore, how
necessary it is to beg you to forget the personality of him who has thus
ventured to address you, and to consider only the truth or error in what
has been said.
FOOTNOTES:
[56] "In the third place, we have to review the method of Comparison,
which is so specially adapted to the study of living bodies, and by
which, above all others, that study must be advanced. In Astronomy, this
method is necessarily inapplicable; and it is not till we arrive at
Chemistry that this third means of investigation can be used, and then
only in subordination to the two others. It is in the study, both
statical and dynamical, of living bodies that it first acquires its full
development; and its use elsewhere can be only through its application
here."--_Comte's Positive Philosophy_, translated by Miss Martineau.
Vol. i. p. 372.
By what method does M. Comte suppose that the equality or inequality of
forces and quantities and the dissimilarity or similarity of
forms--points of some slight importance not only in Astronomy and
Physics, but even in Mathematics,--are ascertained, if not by
Comparison?
[57] "Proceeding to the second class of means,--Experiment cannot but be
less and less decisive, in proportion to the complexity of the phænomena
to be explored; and therefore we saw this resource to be less effectual
in chemistry than in physics: and we now find that it is eminently
useful in chemistry in comparison with physiology. _In fact, the nature
of the phænomena seems to offer almost insurmountable impediments to any
extensive and prolific application of such a procedure in
biology._"--COMTE, vol. i. p. 367.
M. Comte, as his manner is, contradicts himself two pages further on,
but that will hardly relieve him from the responsibility of such a
paragraph as the above.
[58] Nouvelle Fonction du Foie considéré comme organe producteur de
matière sucrée chez l'Homme et les Animaux, par M. Claude Bernard.
[59] "_Natural Groups given by Type, not by Definition...._ The class is
steadily fixed, though not precisely limited; it is given, though not
circumscribed; it is determined, not by a boundary-line without, but by
a central point within; not by what it strictly excludes, but what it
eminently includes; by an example, not by a precept; in short, instead
of Definition we have a _Type_ for our director. A type is an example of
any class, for instance, a species of a genus, which is considered as
eminently possessing the characters of the class. All the species which
have a greater affinity with this type-species than with any others,
form the genus, and are ranged about it, deviating from it in various
directions and different degrees."--_Whewell, The Philosophy of the
Inductive Sciences_, vol. i. pp. 476-7.
[60] Save for the pleasure of doing so, I need hardly point out my
obligations to Mr. J. S. Mill's "System of Logic," in this view of
scientific method.
XI
ON THE PERSISTENT TYPES OF
ANIMAL LIFE.
The successive modifications which the views of physical geologists have
undergone since the infancy of their science, with regard to the amount
and the nature of the changes which the crust of the globe has suffered,
have all tended in one direction, viz. towards the establishment of the
belief, that throughout that vast series of ages which was occupied by
the deposition of the stratified rocks, and which may be called
"geological time," (to distinguish it from the "historical time" which
followed, and the "pre-geological time," which preceded it) the
intensity and the character of the physical forces which have been in
operation, have varied within but narrow limits; so that, even in
Silurian or Cambrian times, the aspect of physical nature must have been
much what it is now.
This uniformitarian view of telluric conditions, so far as geological
time is concerned, is, however, perfectly consistent with the notion of
a totally different state of things in antecedent epochs, and the
strongest advocate of such "physical uniformity" during the time of
which we have a record might, with perfect consistency, hold the
so-called "nebular hypothesis," or any other view involving the
conception of a long series of states very different from that which we
now know, and whose succession occupied pre-geological time.
The doctrine of physical uniformity and that of physical progression are
therefore perfectly consistent, if we regard geological time as having
the same relation to pre-geological time as historical time has to it.
The accepted doctrines of palæontology are by no means in harmony with
these tendencies of physical geology. It is generally believed that
there is a vast contrast between the ancient and the modern organic
worlds--it is incessantly assumed that we are acquainted with the
beginning of life, and with the primal manifestation of each of its
typical forms: nor does the fact that the discoveries of every year
oblige the holders of these views to change their ground, appear
sensibly to affect the tenacity of their adhesion.
Without at all denying the considerable positive differences which
really exist between the ancient and the modern forms of life, and
leaving the negative ones to be met by the other lines of argument, an
impartial examination of the facts revealed by palæontology seems to
show that these differences and contrasts have been greatly exaggerated.
Thus, of some two hundred known orders of plants, not one is exclusively
fossil. Among animals, there is not a single totally extinct class; and
of the orders, at the outside not more than seven per cent. are
unrepresented in the existing creation.
Again, certain well marked forms of living beings have existed through
enormous epochs, surviving not only the changes of physical conditions,
but persisting comparatively unaltered, while other forms of life have
appeared and disappeared. Some forms may be termed "persistent types" of
life; and examples of them are abundant enough in both the animal and
the vegetable worlds.
Among plants, for instance, ferns, club mosses, and _Coniferæ_, some of
them apparently generically identical with those now living, are met
with as far back as the carboniferous epoch; the cone of the oolitic
_Araucaria_ is hardly distinguishable from that of existing species; a
species of _Pinus_ has been discovered in the Purbecks, and a walnut
(_Juglans_) in the cretaceous rocks.[61] All these are types of
vegetable structure, abounding at the present day; and surely it is a
most remarkable fact to find them persisting with so little change
through such vast epochs.
Every sub-kingdom of animals yields instances of the same kind. The
_Globigerina_ of the Atlantic soundings is identical with the cretaceous
species of the same genus; and the casts of lower Silurian
_Foraminifera_, recently described by Ehrenberg, assure us of the very
close resemblance between the oldest and the newest forms of many of the
_Protozoa_.
Among the _Coelenterata_, the tabulate corals of the Silurian epoch
are wonderfully like the millepores of our own seas, as every one may
convince himself who compares _Heliolites_ with _Heliopora_.
Turning to the _Mollusca_, the genera _Crania_, _Discina_, _Lingula_,
have persisted from the Silurian epoch to the present day, with so
little change, that very competent malacologists are sometimes puzzled
to distinguish the ancient from the modern species. _Nautili_ have a
like range, and the shell of the liassic _Loligo_ is similar to that of
the "squid" of our own seas. Among the _Annulosa_, the carboniferous
insects are in several cases referable to existing genera, as are the
_Arachnida_, the highest group of which, the scorpions, is represented
in the coal by a genus differing from its living congeners only in the
disposition of its eyes.
The vertebrate sub-kingdom furnishes many examples of the same kind. The
_Ganoidei_ and _Elasmobranchii_ are known to have persisted from at
least the middle of the Palæozoic epoch to our own times, without
exhibiting a greater amount of deviation from the typical characters of
these orders, than may be found within their limits at the present day.
Among the _Reptilia_, the highest group, that of the _Crocodilia_, was
represented at the beginning of the Mesozoic epoch, if not earlier, by
species identical in the essential character of their organization with
those now living, and presenting differences only in such points as the
form of the articular faces of their vertebræ, in the extent to which
the nasal passages are separated from the mouth by bone, and in the
proportions of the limbs. Even such imperfect knowledge as we possess of
the ancient mammalian fauna leads to the belief that certain of its
types, such as that of the _Marsupialia_, have persisted with no greater
change through as vast a lapse of time.
It is difficult to comprehend the meaning of such facts as these, if we
suppose that each species of animal and plant, or each great type of
organization, was formed and placed upon the surface of the globe at
long intervals by a distinct act of creative power; and it is well to
recollect that such an assumption is as unsupported by tradition or
revelation as it is opposed to the general analogy of Nature.
If, on the other hand, we view "Persistent Types," in relation to that
hypothesis which supposes the species of living beings living at any
time to be the result of the gradual modification of pre-existing
species--a hypothesis which though unproven, and sadly damaged by some
of its supporters, is yet the only one to which physiology lends any
countenance--their existence would seem to show, that the amount of
modification which living beings have undergone during geological time
is but very small in relation to the whole series of changes which they
have suffered. In fact, palæontology and physical geology are in perfect
harmony, and coincide in indicating that all we know of the conditions
in our world during geological time, is but the last term of a vast and,
so far as our present knowledge reaches, unrecorded progression.
FOOTNOTES:
[61] I state these facts on the authority of my friend Dr. Hooker.--T.
H. H.
XII
TIME AND LIFE.
MR. DARWIN'S "ORIGIN OF SPECIES"
Everyone knows that that superficial film of the earth's substance,
hardly ten miles thick, which is accessible to human investigation, is
composed for the most part of beds or strata of stone, the consolidated
muds and sands of former seas and lakes, which have been deposited one
upon the other, and hence are the older the deeper they lie. These
multitudinous strata present such resemblances and differences among
themselves that they are capable of classification into groups or
formations, and these formations again are brigaded together into still
larger assemblages, called by the older geologists, primary, secondary,
and tertiary; by the moderns, palæozoic, mesozoic, and cainozoic: the
basis of the former nomenclature being the relative age of the groups of
strata; that of the latter, the kinds of living forms contained in them.
Though but a film if compared with the total diameter of our planet, the
total series of formations is vast indeed when measured by any human
standard, and, as all action implies time, so are we compelled to regard
these mineral masses as a measure of the time which has elapsed during
their accumulation. The amount of the time which they represent is, of
course, in the inverse proportion of the intensity of the forces which
have been in operation. If, in the ancient world, mud and sand
accumulated on sea-bottoms at tenfold their present rate, it is clear
that a bed of mud or sand ten feet thick would have been formed then in
the same time as a stratum of similar materials one foot thick would be
formed now, and _vice versâ_.
At the outset of his studies, therefore, the physical geologist had to
choose between two hypotheses; either, throughout the ages which are
represented by the accumulated strata, and which we may call _geologic
time_, the forces of nature have operated with much the same average
intensity as at present, and hence the lapse of time which they
represent must be something prodigious and inconceivable, or, in the
primeval epochs, the natural powers were infinitely more intense than
now, and hence the time through which they acted to produce the effects
we see was comparatively short.
The earlier geologists adopted the latter view almost with one consent.
For they had little knowledge of the present workings of nature, and
they read the records of geologic time as a child reads the history of
Rome or Greece, and fancies that antiquity was grand, heroic, and unlike
the present because it is unlike his little experience of the present.
Even so the earlier observers were moved with wonder at the seeming
contrast between the ancient and the present order of nature. The
elemental forces seemed to have been grander and more energetic in
primeval times. Upheaved and contorted, rifted and fissured, pierced by
dykes of molten matter or worn away over vast areas by aqueous action,
the older rocks appeared to bear witness to a state of things far
different from that exhibited by the peaceful epoch on which the lot of
man has fallen.
But by degrees thoughtful students of geology have been led to perceive
that the earliest efforts of nature have been by no means the grandest.
Alps and Andes are children of yesterday when compared with Snowdon and
the Cumberland hills; and the so-called glacial epoch--that in which
perhaps the most extensive physical changes of which any record remains
occurred--is the last and the newest of the revolutions of the globe.
And in proportion as physical geography--which is the geology of our own
epoch--has grown into a science, and the present order of nature has
been ransacked to find what, _hibernicè_, we may call precedents for the
phenomena of the past, so the apparent necessity of supposing the past
to be widely different from the present has diminished.
The transporting power of the greatest deluge which can be imagined
sinks into insignificance beside that of the slowly floating, slowly
melting iceberg, or the glacier creeping along at its snail's pace of a
yard a day. The study of the deltas of the Nile, the Ganges, and the
Mississippi has taught us how slow is the wearing action of water, how
vast its effects when time is allowed for its operation. The reefs of
the Pacific, the deep-sea soundings of the Atlantic, show that it is to
the slow-growing coral and to the imperceptible animalcule, which lives
its brief space and then adds its tiny shell to the muddy cairn left by
its brethren and ancestors, that we must look as the agents in the
formation of limestone and chalk, and not to hypothetical oceans
saturated with calcareous salts and suddenly depositing them.
And while the inquirer has thus learnt that existing forces--_give them
time_--are competent to produce all the physical phenomena we meet with
in the rocks, so, on the other side, the study of the marks left in the
ancient strata by past physical actions shows that these were similar to
those which now obtain. Ancient beaches are met with whose pebbles are
like those found on modern shores; the hardened sea-sands of the oldest
epochs show ripple-marks, such as may now be found on every sandy coast;
nay, more, the pits left by ancient rain-drops prove that even in the
very earliest ages, the "bow in the clouds" must have adorned the
palæozoic firmament. So that if we could reverse the legend of the Seven
Sleepers,--if we could sleep back through the past, and awake a million
ages before our own epoch, in the midst of the earliest geologic
times,--there is no reason to believe that sea, or sky, or the aspect of
the land would warn us of the marvellous retrospection.
Such are the beliefs which modern physical geologists hold, or, at any
rate, tend towards holding. But, in so doing, it is obvious that they by
no means prejudge the question, as to what the physical condition of the
globe may have been before our chapters of its history begin, in what
may be called (with that licence which is implied in the often-used term
"prehistoric epoch") "pregeologic time." The views indicated, in fact,
are not only quite consistent with the hypothesis, that, in the still
earlier period referred to, the condition of our world was very
different; but they may be held by some to necessitate that hypothesis.
The physical philosopher who is accurately acquainted with the velocity
of a cannon-ball, and the precise character of the line which it
traverses for a yard of its course, is necessitated by what he knows of
the laws of nature to conclude that it came from a certain spot, whence
it was impelled by a certain force, and that it has followed a certain
trajectory. In like manner, the student of physical geology, who fully
believes in the uniformity of the general condition of the earth through
geologic time, may feel compelled by what he knows of causation, and by
the general analogy of nature, to suppose that our solar system was once
a nebulous mass, that it gradually condensed, that it broke up into that
wonderful group of harmoniously rolling balls we call planets and
satellites, and that then each of these underwent its appointed
metamorphosis, until at last our own share of the cosmic vapour passed
into that condition in which we first meet with definite records of its
state, and in which it has since, with comparatively little change,
remained.
The doctrine of uniformity and the doctrine of progression are,
therefore, perfectly consistent; perhaps, indeed, they might be shown to
be necessarily connected with one another.
If, however, the condition of the world, which has obtained throughout
geologic time, is but the sequel to a vast series of changes which took
place in pregeologic time, then it seems not unlikely that the duration
of this latter is to that of the former as the vast extent of geologic
time is to the length of the brief epoch we call the historical period;
and that even the oldest rocks are records of an epoch almost infinitely
remote from that which could have witnessed the first shaping of our
globe.
It is probable that no modern geologist would hesitate to admit the
general validity of these reasonings when applied to the physics of his
subject, whence it is the more remarkable that the moment the question
changes from one of physics and chemistry to one of natural history,
scientific opinions and the popular prejudices, which reflect them in a
distorted form, undergo a sudden metamorphosis. Geologists and
palæontologists write about the "beginning of life" and the
"first-created forms of living beings," as if they were the most
familiar things in the world; and even cautious writers seem to be on
quite friendly terms with the "archetype" whereby the Creator was guided
"amidst the crash of falling worlds." Just as it used to be imagined
that the ancient universe was physically opposed to the present, so it
is still widely assumed that the living population of our globe, whether
animal or vegetable, in the older epochs, exhibited forms so strikingly
contrasted with those which we see around us, that there is hardly
anything in common between the two. It is constantly tacitly assumed
that we have before us all the forms of life which have ever existed;
and though the progress of knowledge, yearly and almost monthly, drives
the defenders of that position from their ground, they entrench
themselves in the new line of defences as if nothing had happened, and
proclaim that the _new_ beginning is the _real_ beginning.
* * * * *
Without for an instant denying or endeavouring to soften down the
considerable positive differences (the negative ones are met by another
line of argument) which undoubtedly obtain between the ancient and the
modern worlds of life, we believe they have been vastly overstated and
exaggerated, and this belief is based upon certain facts whose value
does not seem to have been fully appreciated, though they have long been
more or less completely known.
The multitudinous kinds of animals and plants, both recent and fossil,
are, as is well known, arranged by zoologists and botanists, in
accordance with their natural relations, into groups which receive the
names of sub-kingdoms, classes, orders, families, genera and species.
Now it is a most remarkable circumstance that, viewed on the great
scale, living beings have differed so little throughout all geologic
time that there is no sub-kingdom and no class wholly extinct or without
living representatives.
If we descend to the smaller groups, we find that the number of orders
of plants is about two hundred; and I have it on the best authority
that not one of these is exclusively fossil; so that there is absolutely
not a single extinct ordinal type of vegetable life; and it is not until
we descend to the next group, or the families, that we find types which
are wholly extinct. The number of orders of animals, on the other hand,
may be reckoned at a hundred and twenty, or thereabouts, and of these,
eight or nine have no living representatives. The proportion of extinct
ordinal types of animals to the existing types, therefore, does not
exceed seven per cent.--a marvellously small proportion when we consider
the vastness of geologic time.
Another class of considerations--of a different kind, it is true, but
tending in the same direction--seems to have been overlooked. Not only
is it true that the general plan of construction of animals and plants
has been the same in all recorded time as at present, but there are
particular kinds of animals and plants which have existed throughout
vast epochs, sometimes through the whole range of recorded time, with
very little change. By reason of this persistency, the typical form of
such a kind might be called a "persistent type," in contradistinction to
those types which have appeared for but a short time in the course of
the world's history. Examples of these persistent types are abundant
enough in both the vegetable and the animal kingdoms. The oldest group
of plants with which we are well acquainted is that of whose remains
coal is constituted; and, so far as they can be identified, the
carboniferous plants are ferns, or club-mosses, or Coniferæ, in many
cases generically identical with those now living!
Among animals, instances of the same kind may be found in every
sub-kingdom. The _Globigerina_ of the Atlantic soundings is identical
with that which occurs in the chalk; and the casts of lower silurian
_Foraminifera_, which Ehrenberg has recently described, seem to indicate
the existence at that remote period of forms singularly like those which
now exist. Among the corals, the palæozoic _Tabulata_ are constructed on
precisely the same type as the modern millepores; and if we turn to
molluscs, the most competent malacologists fail to discover any generic
distinction between the _Craniæ_, _Lingulæ_, and _Discinæ_ of the
silurian rocks and those which now live. Our existing _Nautilus_ has its
representative species in every great formation, from the oldest to the
newest; and _Loligo_, the squid of modern seas, appears in the lias, or
at the bottom of the mesozoic series, in a form, at most, specifically
different from its living congeners. In the great assemblage of annulose
animals, the two highest classes, the insects and spider tribe, exhibit
a wonderful persistency of type. The cockroaches of the carboniferous
epoch are exceedingly similar to those which now run about our
coal-cellars; and its locusts, termites, and dragon-flies are closely
allied to the members of the same groups which now chirrup about our
fields, undermine our houses, or sail with swift grace about the banks
of our sedgy pools. And, in like manner, the palæozoic scorpions can
only be distinguished by the eye of a naturalist from the modern ones.
Finally, with respect to the _Vertebrata_, the same law holds good:
certain types, such as those of the ganoid and placoid fishes, having
persisted from the palæozoic epoch to the present time without a greater
amount of deviation from the normal standard than that which is seen
within the limits of the group as it now exists. Even among the
_Reptilia_--the class which exhibits the largest proportion of entirely
extinct forms of any--one type, that of the _Crocodilia_, has persisted
from at least the commencement of the Mesozoic epoch up to the present
time with so much constancy, that the amount of change which it exhibits
may fairly, in relation to the time which has elapsed, be called
insignificant. And the imperfect knowledge we have of the ancient
mammalian population of our earth leads to the belief that certain of
its types, such as that of the _Marsupialia_, have persisted with
correspondingly little change through a similar range of time.
Thus it would appear to be demonstrable, that, notwithstanding the great
change which is exhibited by the animal population of the world as a
whole, certain types have persisted comparatively without alteration,
and the question arises, What bearing have such facts as these on our
notions of the history of life through geological time? The answer to
this question would seem to depend on the view we take respecting the
origin of species in general. If we assume that every species of animal
and of plant was formed by a distinct act of creative power, and if the
species which have incessantly succeeded one another were placed upon
the globe by these separate acts, then the existence of persistent types
is simply an unintelligible irregularity. Such assumption, however, is
as unsupported by tradition or by Revelation as it is opposed by the
analogy of the rest of the operations of nature; and those who imagine
that, by adopting any such hypothesis, they are strengthening the hands
of the advocates of the letter of the Mosaic account, are simply
mistaken. If, on the other hand, we adopt that hypothesis to which alone
the study of physiology lends any support--that hypothesis which, having
struggled beyond the reach of those fatal supporters, the Telliameds and
Vestigiarians, who so nearly caused its suffocation by wind in early
infancy, is now winning at least the provisional assent of all the best
thinkers of the day--the hypothesis that the forms or species of living
beings, as we know them, have been produced by the gradual modification
of pre-existing species--then the existence of persistent types seems to
teach us much. Just as a small portion of a great curve appears
straight, the apparent absence of change in direction of the line being
the exponent of the vast extent of the whole, in proportion to the part
we see; so, if it be true that all living species are the result of the
modification of other and simpler forms, the existence of these little
altered persistent types, ranging through all geological time, must
indicate that they are but the final terms of an enormous series of
modifications, which had their being in the great lapse of pregeologic
time, and are now perhaps for ever lost.
In other words, when rightly studied, the teachings of palæontology are
at one with those of physical geology. Our farthest explorations carry
us back but a little way above the mouth of the great river of Life:
where it arose, and by what channels the noble tide has reached the
point when it first breaks upon our view, is hidden from us.
The foregoing pages contain the substance of a lecture delivered before
the Royal Institution of Great Britain many months ago, and of course
long before the appearance of the remarkable work on the "Origin of
Species," just published by Mr. Darwin, who arrives at very similar
conclusions. Although, in one sense, I might fairly say that my own
views have been arrived at independently, I do not know that I can claim
any equitable right to property in them; for it has long been my
privilege to enjoy Mr. Darwin's friendship, and to profit by
corresponding with him, and by, to some extent, becoming acquainted with
the workings of his singularly original and well-stored mind. It was in
consequence of my knowledge of the general tenor of the researches in
which Mr. Darwin had been so long engaged; because I had the most
complete confidence in his perseverance, his knowledge, and, above all
things, his high-minded love of truth; and, moreover, because I found
that the better I became acquainted with the opinions of the best
naturalists regarding the vexed question of species, the less fixed they
seemed to be, and the more inclined they were to the hypothesis of
gradual modification, that I ventured to speak as strongly as I have
done in the final paragraphs of my discourse.
Thus, my daw having so many borrowed plumes, I see no impropriety in
making a tail to this brief paper by taking another handful of feathers
from Mr. Darwin; endeavouring to point out in a few words, in fact,
what, as I gather from the perusal of his book, his doctrines really
are, and on what sort of basis they rest. And I do this the more
willingly, as I observe that already the hastier sort of critics have
begun, not to review my friend's book, but to howl over it in a manner
which must tend greatly to distract the public mind.
No one will be better satisfied than I to see Mr. Darwin's book refuted,
if any person be competent to perform that feat; but I would suggest
that refutation is retarded, not aided, by mere sarcastic
misrepresentation. Every one who has studied cattle-breeding, or turned
pigeon-fancier, or "pomologist," must have been struck by the extreme
modifiability or plasticity of those kinds of animals and plants which
have been subjected to such artificial conditions as are imposed by
domestication. Breeds of dogs are more different from one another than
are the dog and the wolf; and the purely artificial races of pigeons, if
their origin were unknown, would most assuredly be reckoned by
naturalists as distinct species and even genera.
These breeds are always produced in the same way. The breeder selects a
pair, one or other, or both, of which present an indication of the
peculiarity he wishes to perpetuate, and then selects from the offspring
of them those which are most characteristic, rejecting the others. From
the selected offspring he breeds again, and, taking the same precautions
as before, repeats the process until he has obtained the precise degree
of divergence from the primitive type at which he aimed.
If he now breeds from the variety thus established for some generations,
taking care always to keep the stock pure, the tendency to produce this
particular variety becomes more and more strongly hereditary; and it
does not appear that there is any limit to the persistency of the race
thus developed.
Men like Lamarck, apprehending these facts, and knowing that varieties
comparable to those produced by the breeder are abundantly found in
nature, and finding it impossible to discriminate in some cases between
varieties and true species, could hardly fail to divine the possibility
that species even the most distinct were, after all, only exceedingly
persistent varieties, and that they had arisen by the modification of
some common stock, just as it is with good reason believed that
turnspits and greyhounds, carrier and tumbler pigeons, have arisen.
But there was a link wanting to complete the parallel. Where in nature
was the analogue of the breeder to be found? How could that operation of
selection, which is his essential function, be carried out by mere
natural agencies? Lamarck did not value this problem; neither did he
admit his impotence to solve it; but he guessed a solution. Now,
guessing in science is a very hazardous proceeding, and Lamarck's
reputation has suffered woefully for the absurdities into which his
baseless suppositions led him.
Lamarck's conjectures, equipped with a new hat and stick, as Sir Walter
Scott was wont to say of an old story renovated, formed the foundation
of the biological speculations of the "Vestiges," a work which has done
more harm to the progress of sound thought on these matters than any
that could be named; and, indeed, I mention it here simply for the
purpose of denying that it has anything in common with what essentially
characterises Mr. Darwin's work.
The peculiar feature of the latter is, in fact, that it professes to
tell us what in nature takes the place of the breeder; what it is that
favours the development of one variety into which a species may run, and
checks that of another; and, finally, shows how this natural selection,
as it is termed, may be the physical cause of the production of species
by modification.
That which takes the place of the breeder and selector in nature is
Death. In a most remarkable chapter, "On the Struggle for Existence,"
Mr. Darwin draws attention to the marvellous destruction of life which
is constantly going on in nature. For every species of living thing, as
for man, "_Eine Bresche ist ein jeder Tag_."--Every species has its
enemies; every species has to compete with others for the necessaries of
existence; the weakest goes to the wall, and death is the penalty
inflicted on all laggards and stragglers. Every variety to which a
species may give rise is either worse or better adapted to surrounding
circumstances than its parent. If worse, it cannot maintain itself
against death, and speedily vanishes again. But if better adapted, it
must, sooner or later, "improve" its progenitor from the face of the
earth, and take its place. If circumstances change, the victor will be
similarly supplanted by its own progeny; and thus, by the operation of
natural causes, unlimited modification may in the lapse of long ages
occur.
For an explanation of what I have here called vaguely "surrounding
circumstances," and of why they continually change--for ample proof that
the "struggle for existence" is a very great reality, and assuredly
_tends_ to exert the influence ascribed to it--I must refer to Mr.
Darwin's book. I believe I have stated fairly the position upon which
his whole theory must stand or fall; and it is not my purpose to
anticipate a full review of his work. If it can be proved that the
process of natural selection, operating upon any species, can give rise
to varieties of species so different from one another that none of our
tests will distinguish them from true species, Mr. Darwin's hypothesis
of the origin of species will take its place among the established
theories of science, be its consequences whatever they may. If, on the
other hand, Mr. Darwin has erred, either in fact or in reasoning, his
fellow-workers will soon find out the weak points in his doctrines, and
their extinction by some nearer approximation to the truth will
exemplify his own principle of natural selection.
In either case the question is one to be settled only by the
painstaking, truth-loving investigation of skilled naturalists. It is
the duty of the general public to await the result in patience; and,
above all things, to discourage, as they would any other crimes, the
attempt to enlist the prejudices of the ignorant, or the
uncharitableness of the bigoted, on either side of the controversy.
XIII
DARWIN ON THE ORIGIN OF SPECIES.
Mr. Darwin's long-standing and well-earned scientific eminence probably
renders him indifferent to that social notoriety which passes by the
name of success; but if the calm spirit of the philosopher have not yet
wholly superseded the ambition and the vanity of the carnal man within
him, he must be well satisfied with the results of his venture in
publishing the "Origin of Species." Overflowing the narrow bounds of
purely scientific circles, the "species question" divides with Italy and
the Volunteers the attention of general society. Everybody has read Mr.
Darwin's book, or, at least, has given an opinion upon its merits or
demerits; pietists, whether lay or ecclesiastic, decry it with the mild
railing which sounds so charitable; bigots denounce it with ignorant
invective; old ladies, of both sexes, consider it a decidedly dangerous
book, and even savans, who have no better mud to throw, quote antiquated
writers to show that its author is no better than an ape himself; while
every philosophical thinker hails it as a veritable Whitworth gun in the
armoury of liberalism, and all competent naturalists and physiologists,
whatever their opinions as to the ultimate fate of the doctrines put
forth, acknowledge that the work in which they are embodied is a solid
contribution to knowledge and inaugurates a new epoch in natural
history.
Nor has the discussion of the subject been restrained within the limits
of conversation. When the public is eager and interested, reviewers must
minister to its wants, and the genuine _littérateur_ is too much in the
habit of acquiring his knowledge from the book he judges--as the
Abyssinian is said to provide himself with steaks from the ox which
carries him--to be withheld from criticism of a profound scientific work
by the mere want of the requisite preliminary scientific acquirement;
while, on the other hand, the men of science who wish well to the new
views, no less than those who dispute their validity, have naturally
sought opportunities of expressing their opinions. Hence it is not
surprising that almost all the critical journals have noticed Mr.
Darwin's work at greater or less length, and so many disquisitions, of
every degree of excellence, from the poor product of ignorance, too
often stimulated by prejudice, to the fair and thoughtful essay of the
candid student of nature, have appeared, that it seems an almost
hopeless task to attempt to say anything new upon the question.
But it may be doubted if the knowledge and acumen of prejudged
scientific opponents, or the subtlety of orthodox special pleaders, have
yet exerted their full force in mystifying the real issues of the great
controversy which has been set afoot, and whose end is hardly likely to
be seen by this generation; so that at this eleventh hour, and even
failing anything new, it may be useful to state afresh that which is
true, and to put the fundamental positions advocated by Mr. Darwin in
such a form that they may be grasped by those whose special studies lie
in other directions; and the adoption of this course may be the more
advisable, because notwithstanding its great deserts, and indeed partly
on account of them, the "Origin of Species" is by no means an easy book
to read--if by reading is implied the full comprehension of an author's
meaning.
We do not speak jestingly in saying that it is Mr. Darwin's misfortune
to know more about the question he has taken up than any man living.
Personally and practically exercised in zoology, in minute anatomy, in
geology; a student of geographical distribution, not on maps and in
museums only, but by long voyages and laborious collection; having
largely advanced each of these branches of science, and having spent
many years in gathering and sifting materials for his present work, the
store of accurately registered facts upon which the author of the
"Origin of Species" is able to draw at will is prodigious.
But this very superabundance of matter must have been embarrassing to a
writer who, for the present, can only put forward an abstract of his
views, and thence it arises, perhaps, that notwithstanding the clearness
of the style, those who attempt fairly to digest the book find much of
it a sort of intellectual pemmican--a mass of facts crushed and pounded
into shape, rather than held together by the ordinary medium of an
obvious logical bond: due attention will, without doubt, discover this
bond, but it is often hard to find.
Again, from sheer want of room, much has to be taken for granted which
might readily enough be proved, and hence, while the adept, who can
supply the missing links in the evidence from his own knowledge,
discovers fresh proof of the singular thoroughness with which all
difficulties have been considered and all unjustifiable supposition
avoided, at every reperusal of Mr. Darwin's pregnant paragraphs, the
novice in biology is apt to complain of the frequency of what he fancies
is gratuitous assumption.
Thus while it may be doubted if, for some years, any one is likely to be
competent to pronounce judgment on all the issues raised by Mr. Darwin,
there is assuredly abundant room for him, who, assuming the humbler,
though perhaps as useful, office of an interpreter between the "Origin
of Species" and the public, contents himself with endeavouring to point
out the nature of the problems which it discusses; to distinguish
between the ascertained facts and the theoretical views which it
contains; and finally, to show the extent to which the explanation it
offers satisfies the requirements of scientific logic. At any rate, it
is this office which we purpose to undertake in the following pages.
It may be safely assumed that our readers have a general conception of
the nature of the objects to which the word "species" is applied; but it
has, perhaps, occurred to few, even of those who are naturalists _ex
professo_, to reflect, that, as commonly employed, the term has a double
sense and denotes two very different orders of relations. When we call
a group of animals, or of plants, a species, we may imply thereby
either, that all these animals or plants have some common peculiarity of
form or structure; or, we may mean that they possess some common
functional character. That part of biological science which deals with
form and structure is called Morphology--that which concerns itself with
function, Physiology--so that we may conveniently speak of these two
senses or aspects of "species"--the one as morphological, the other as
physiological. Regarded from the former point of view, a species is
nothing more than a kind of animal or plant, which is distinctly
definable from all others, by certain constant and not merely sexual,
morphological peculiarities. Thus horses form a species, because the
group of animals to which that name is applied is distinguished from all
others in the world by the following constantly associated characters.
They have 1. A vertebral column; 2. Mammæ; 3. A placental embryo; 4.
Four legs; 5. A single well-developed toe in each foot provided with a
hoof; 6. A bushy tail; and 7. Callosities on the inner sides of both the
fore and the hind legs. The asses again, form a distinct species,
because, with the same characters, as far as the fifth in the above
list, all asses have tufted tails, and have callosities only on the
inner side of the fore-legs. If animals were discovered having the
general characters of the horse, but sometimes with callosities only on
the fore legs, and more or less tufted tails; or animals having the
general characters of the ass, but with more or less bushy tails, and
sometimes with callosities on both pairs of legs, besides being
intermediate in other respects--the two species would have to be merged
into one. They could no longer be regarded as morphologically distinct
species, for they would not be distinctly definable one from the other.
However bare and simple this definition of species may appear to be, we
confidently appeal to all practical naturalists, whether zoologists,
botanists, or palæontologists, to say if, in the vast majority of cases,
they know, or mean to affirm, anything more of the group of animals or
plants they so denominate than what has just been stated. Even the most
decided advocates of the received doctrines respecting species admit
this.
"I apprehend," says Professor Owen,[62] "that few naturalists
now-a-days, in describing and proposing a name for what they call 'a new
_species_,' use that term to signify what was meant by it twenty or
thirty years ago, that is, an originally distinct creation, maintaining
its primitive distinction by obstructive generative peculiarities. The
proposer of the new species now intends to state no more than he
actually knows; as for example, that the differences in which he founds
the specific character are constant in individuals of both sexes, so far
as observation has reached; and that they are not due to domestication
or to artificially superinduced external circumstances, or to any
outward influence within his cognizance; that the species is wild, or is
such as it appears by nature."
If we consider, in fact, that by far the largest proportion of recorded
existing species are known only by the study of their skins, or bones,
or other lifeless exuvia; that we are acquainted with none, or next to
none, of their physiological peculiarities, beyond those which can be
deduced from their structure, or are open to cursory observation; and
that we cannot hope to learn more of any of those extinct forms of life
which now constitute no inconsiderable proportion of the known Flora and
Fauna of the world; it is obvious that the definitions of these species
can be only of a purely structural or morphological character. It is
probable that naturalists would have avoided much confusion of ideas if
they had more frequently borne these necessary limitations of our
knowledge in mind. But while it may safely be admitted that we are
acquainted with only the morphological characters of the vast majority
of species--the functional or physiological peculiarities of a few have
been carefully investigated, and the result of that study forms a large
and most interesting portion of the physiology of reproduction.
The student of nature wonders the more and is astonished the less, the
more conversant he becomes with her operations; but of all the perennial
miracles she offers to his inspection, perhaps the most worthy of
admiration is the development of a plant or of an animal from its
embryo. Examine the recently laid egg of some common animal, such as a
salamander or a newt. It is a minute spheroid in which the best
microscope will reveal nothing but a structureless sac, enclosing a
glairy fluid, holding granules in suspension. But strange possibilities
lie dormant in that semi-fluid globule. Let a moderate supply of warmth
reach its watery cradle, and the plastic matter undergoes changes so
rapid and yet so steady and purpose-like in their succession, that one
can only compare them to those operated by a skilled modeller upon a
formless lump of clay. As with an invisible trowel, the mass is divided
and subdivided into smaller and smaller portions, until it is reduced to
an aggregation of granules not too large to build withal the finest
fabrics of the nascent organism. And, then, it is as if a delicate
finger traced out the line to be occupied by the spinal column, and
moulded the contour of the body; pinching up the head at one end, the
tail at the other, and fashioning flank and limb into due salamandrine
proportions, in so artistic a way, that, after watching the process hour
by hour, one is almost involuntarily possessed by the notion, that some
more subtle aid to vision than an achromatic would show the hidden
artist, with his plan before him, striving with skilful manipulation to
perfect his work.
As life advances, and the young amphibian ranges the waters, the terror
of his insect contemporaries, not only are the nutritious particles
supplied by its prey, by the addition of which to its frame growth takes
place, laid down, each in its proper spot, and in such due proportion to
the rest, as to reproduce the form, the colour and the size,
characteristic of the parental stock; but even the wonderful powers of
reproducing lost parts possessed by these animals are controlled by the
same governing tendency. Cut off the legs, the tail, the jaws,
separately or all together, and, as Spallanzani showed long ago, these
parts not only grow again, but the redintegrated limb is formed on the
same type as those which were lost. The new jaw or leg is a newt's, and
never by any accident more like that of a frog. What is true of the newt
is true of every animal and of every plant; the acorn tends to build
itself up again into a woodland giant such as that from whose twig it
fell; the spore of the humblest lichen reproduces the green or brown
incrustation which gave it birth; and at the other end of the scale of
life, the child that resembled neither the paternal nor the maternal
side of the house would be regarded as a kind of monster.
So that the one end to which in all living beings the formative impulse
is tending--the one scheme which the Archæus of the old speculators
strives to carry out, seems to be to mould the offspring into the
likeness of the parent. It is the first great law of reproduction, that
the offspring tends to resemble its parent or parents, more closely than
anything else.
Science will some day show us how this law is a necessary consequence of
the more general laws which govern matter; but for the present, more can
hardly be said than that it appears to be in harmony with them. We know
that the phenomena of vitality are not something apart from other
physical phenomena, but one with them; and matter and force are the two
names of the one artist who fashions the living as well as the lifeless.
Hence living bodies should obey the same great laws as other
matter--nor, throughout nature, is there a law of wider application than
this, that a body impelled by two forces takes the direction of their
resultant. But living bodies may be regarded as nothing but extremely
complex bundles of forces held in a mass of matter, as the complex
forces of a magnet are held in the steel by its coercive force; and
since the differences of sex are comparatively slight, or, in other
words, the sum of the forces in each has a very similar tendency, their
resultant, the offspring, may reasonably be expected to deviate but
little from a course parallel to either, or to both.
Represent the reason of the law to ourselves by what physical metaphor
or analogy we will, however, the great matter is to apprehend its
existence and the importance of the consequences deducible from it. For
things which are like to the same are like to one another, and if, in a
great series of generations, every offspring is like its parent, it
follows that all the offspring and all the parents must be like one
another; and that, given an original parental stock with the opportunity
of undisturbed multiplication, the law in question necessitates the
production, in course of time, of an indefinitely large group, the whole
of whose members are at once very similar and are blood relations,
having descended from the same parent, or pair of parents. The proof
that all the members of any given group of animals, or plants, had thus
descended, would be ordinarily considered sufficient to entitle them to
the rank of physiological species, for most physiologists consider
species to be definable as "the offspring of a single primitive stock."
But though it is quite true that all those groups we call species _may_,
according to the known laws of reproduction, have descended from a
single stock, and though it is very likely they really have done so, yet
this conclusion rests on deduction and can hardly hope to establish
itself upon a basis of observation. And the primitiveness of the
supposed single stock, which, after all, is the essential part of the
matter, is not only a hypothesis, but one which has not a shadow of
foundation, if by "primitive" be meant "independent of any other living
being." A scientific definition, of which an unwarrantable hypothesis
forms an essential part, carries its condemnation within itself; but
even supposing such a definition were, in form, tenable, the
physiologist who should attempt to apply it in nature would soon find
himself involved in great, if not inextricable difficulties. As we have
said, it is indubitable that offspring _tend_ to resemble the parental
organism, but it is equally true that the similarity attained never
amounts to identity, either in form or in structure. There is always a
certain amount of deviation, not only from the precise characters of a
single parent, but when, as in most animals and many plants, the sexes
are lodged in distinct individuals, from an exact mean between the two
parents. And, indeed, on general principles, this slight deviation seems
as intelligible as the general similarity, if we reflect how complex the
co-operating "bundles of forces" are, and how improbable it is that, in
any case, their true resultant shall coincide with any mean between the
more obvious characters of the two parents. Whatever be its cause,
however, the co-existence of this tendency to minor variation with the
tendency to general similarity, is of vast importance in its bearing on
the question of the origin of species.
As a general rule, the extent to which an offspring differs from its
parent is slight enough; but, occasionally, the amount of difference is
much more strongly marked, and then the divergent offspring receives the
name of a Variety. Multitudes, of what there is every reason to believe
are such varieties, are known, but the origin of very few has been
accurately recorded, and of these we will select two as more especially
illustrative of the main features of variation. The first of them is
that of the "Ancon," or "Otter" sheep, of which a careful account is
given by Colonel David Humphreys, F.R.S., in a letter to Sir Joseph
Banks, published in the Philosophical Transactions for 1813. It appears
that one Seth Wright, the proprietor of a farm on the banks of the
Charles River, in Massachusetts, possessed a flock of fifteen ewes and a
ram of the ordinary kind. In the year 1791, one of the ewes presented
her owner with a male lamb, differing, for no assignable reason, from
its parents by a proportionally long body and short bandy legs, whence
it was unable to emulate its relatives in those sportive leaps over the
neighbours' fences, in which they were in the habit of indulging, much
to the good farmer's vexation.
The second case is that detailed by a no less unexceptionable authority
than Réaumur, in his "Art de faire éclorre les poulets." A Maltese
couple, named Kelleia, whose hands and feet were constructed upon the
ordinary human model, had born to them a son, Gratio, who possessed six
perfectly moveable fingers on each hand and six toes, not quite so well
formed, on each foot. No cause could be assigned for the appearance of
this unusual variety of the human species.
Two circumstances are well worthy of remark in both these cases. In
each, the variety appears to have arisen in full force, and, as it were,
_per saltum_; a wide and definite difference appearing, at once,
between the Ancon ram and the ordinary sheep; between the six-fingered
and six-toed Gratio Kelleia and ordinary men. In neither case is it
possible to point out any obvious reason for the appearance of the
variety. Doubtless there were determining causes for these as for all
other phenomena; but they do not appear, and we can be tolerably certain
that what are ordinarily understood as changes in physical conditions,
as in climate, in food, or the like, did not take place and had nothing
to do with the matter. It was no case of what is commonly called
adaptation to circumstances; but, to use a conveniently erroneous
phrase, the variations arose spontaneously. The fruitless search after
final causes leads their pursuers a long way; but even those hardy
teleologists, who are ready to break through all the laws of physics in
chase of their favourite will-o'-the-wisp, may be puzzled to discover
what purpose could be attained by the stunted legs of Seth Wright's ram
or the hexadactyle members of Gratio Kelleia.
Varieties then arise we know not why; and it is more than probable that
the majority of varieties have arisen in the spontaneous manner, though
we are, of course, far from denying that they may be traced, in some
cases, to distinct external influences, which are assuredly competent to
alter the character of the tegumentary covering, to change colour, to
increase or diminish the size of muscles, to modify constitution, and,
among plants, to give rise to the metamorphosis of stamens into petals,
and so forth. But however they may have arisen, what especially
interests us at present is, to remark that, once in existence, varieties
obey the fundamental law of reproduction that like tends to produce
like, and their offspring exemplify it by tending to exhibit the same
deviation from the parental stock as themselves. Indeed, there seems to
be, in many instances, a pre-potent influence about a newly-arisen
variety which gives it what one may call an unfair advantage over the
normal descendants from the same stock. This is strikingly exemplified
by the case of Gratio Kelleia, who married a woman with the ordinary
pentadactyle extremities, and had by her four children, Salvator,
George, André, and Marie. Of these children Salvator, the eldest boy,
had six fingers and six toes, like his father; the second and third,
also boys, had five fingers and toes, like their mother, though the
hands and feet of George were slightly deformed; the last, a girl, had
five fingers and toes, but the thumbs were slightly deformed. The
variety thus reproduced itself purely in the eldest, while the normal
type reproduced itself purely in the third, and almost purely in the
second and last: so that it would seem, at first, as if the normal type
were more powerful than the variety. But all these children grew up and
intermarried with normal wives and husbands, and then, note what took
place: Salvator had four children, three of whom exhibited the
hexadactyle members of their grandfather and father, while the youngest
had the pentadactyle limbs of the mother and grandmother; so that here,
notwithstanding a double pentadactyle dilution of the blood, the
hexadactyle variety had the best of it. The same pre-potency of the
variety was still more markedly exemplified in the progeny of two of the
other children, Marie and George. Marie (whose thumbs only were
deformed) gave birth to a boy with six toes, and three other normally
formed children; but George, who was not quite so pure a pentadactyle,
begot, first, two girls, each of whom had six fingers and toes; then a
girl with six fingers on each hand and six toes on the right foot, but
only five toes on the left; and lastly, a boy with only five fingers and
toes. In these instances, therefore, the variety, as it were, leaped
over one generation to reproduce itself in full force in the next.
Finally, the purely pentadactyle André was the father of many children,
not one of whom departed from the normal parental type.
If a variation which approaches the nature of a monstrosity can strive
thus forcibly to reproduce itself, it is not wonderful that less
aberrant modifications should tend to be preserved even more strongly;
and the history of the Ancon sheep is, in this respect, particularly
instructive. With the "'cuteness" characteristic of their nation, the
neighbours of the Massachusetts farmer imagined it would be an excellent
thing if all his sheep were imbued with the stay-at-home tendencies
enforced by nature upon the newly-arrived ram; and they advised Wright
to kill the old patriarch of his fold, and instal the Ancon ram in his
place. The result justified their sagacious anticipations, and coincided
very nearly with what occurred to the progeny of Gratio Kelleia. The
young lambs were almost always either pure Ancons, or pure ordinary
sheep.[63] But when sufficient Ancon sheep were obtained to interbreed
with one another, it was found that the offspring was always pure Ancon.
Colonel Humphreys, in fact, states that he was acquainted with only "one
questionable case of a contrary nature." Here, then, is a remarkable and
well-established instance, not only of a very distinct race being
established _per saltum_, but of that race breeding "true" at once, and
showing no mixed forms, even when crossed with another breed.
By taking care to select Ancons of both sexes, for breeding from, it
thus became easy to establish an extremely well-marked race, so peculiar
that even when herded with other sheep, it was noted that the Ancons
kept together, and there is every reason to believe that the existence
of this breed might have been indefinitely protracted; but the
introduction of the Merino sheep, which were not only very superior to
the Ancons in wool and meat, but quite as quiet and orderly, led to the
complete neglect of the new breed, so that, in 1813, Colonel Humphreys
found it difficult to obtain the specimen whose skeleton was presented
to Sir Joseph Banks. We believe that, for many years, no remnant of it
has existed in the United States.
Gratio Kelleia was not the progenitor of a race of six-fingered men, as
Seth Wright's ram became a nation of Ancon sheep, though the tendency
of the variety to perpetuate itself appears to have been fully as strong
in the one case as in the other. And the reason of the difference is not
far to seek. Seth Wright took care not to weaken the Ancon blood by
matching his Ancon ewes with any but males of the same variety, while
Gratio Kelleia's sons were too far removed from the patriarchal times to
intermarry with their sisters; and his grandchildren seem not to have
been attracted by their six-fingered cousins. In other words, in the one
example a race was produced, because, for several generations, care was
taken to _select_ both parents of the breeding stock, from animals
exhibiting a tendency to vary in the same direction, while in the other
no race was evolved, because no such selection was exercised. A race is
a propagated variety, and as, by the laws of reproduction, offspring
tend to assume the parental form, they will be more likely to propagate
a variation exhibited by both parents than that possessed by only one.
There is no organ of the body of an animal which may not, and does not,
occasionally, vary more or less from the normal type; and there is no
variation which may not be transmitted, and which, if selectively
transmitted, may not become the foundation of a race. This great truth,
sometimes forgotten by philosophers, has long been familiar to practical
agriculturists and breeders: and upon it rest all the methods of
improving the breeds of domestic animals, which for the last century
have been followed with so much success in England. Colour, form, size,
texture of hair or wool, proportions of various parts, strength or
weakness of constitution, tendency to fatten or to remain lean, to give
much or little milk, speed, strength, temper, intelligence, special
instincts; there is not one of these characters whose transmission is
not an every-day occurrence within the experience of cattle-breeders,
stock-farmers, horse-dealers, and dog and poultry fanciers. Nay, it is
only the other day that an eminent physiologist, Dr. Brown Sequard,
communicated to the Royal Society his discovery that epilepsy,
artificially produced in guinea-pigs, by a means which he has
discovered, is transmitted to their offspring.
But a race, once produced, is no more a fixed and immutable entity than
the stock whence it sprang; variations arise among its members, and as
these variations are transmitted like any others, new races may be
developed out of the pre-existing ones _ad infinitum_, or, at least,
within any limit at present determined. Given sufficient time and
sufficiently careful selection, and the multitude of races which may
arise from a common stock is as astonishing as are the extreme
structural differences which they may present. A remarkable example of
this is to be found in the rock-pigeon, which Mr. Darwin has, in our
opinion, satisfactorily demonstrated to be the progenitor of all our
domestic pigeons, of which there are certainly more than a hundred
well-marked races. The most noteworthy of these races are, the four
great stocks known to the "fancy" as tumblers, pouters, carriers, and
fantails; birds which not only differ most singularly in size, colour,
and habits, but in the form of the beak and of the skull; in the
proportions of the beak to the skull; in the number of tail-feathers; in
the absolute and relative size of the feet; in the presence or absence
of the uropygial gland; in the number of vertebræ in the back; in short,
in precisely those characters in which the genera and species of birds
differ from one another.
And it is most remarkable and instructive to observe, that none of these
races can be shown to have been originated by the action of changes in
what are commonly called external circumstances, upon the wild
rock-pigeon. On the contrary, from time immemorial, pigeon fanciers have
had essentially similar methods of treating their pets, which have been
housed, fed, protected and cared for in much the same way in all
pigeonries. In fact, there is no case better adapted than that of the
pigeons, to refute the doctrine which one sees put forth on high
authority, that "no other characters than those founded on the
development of bone for the attachment of muscles" are capable of
variation. In precise contradiction of this hasty assertion, Mr.
Darwin's researches prove that the skeleton of the wings in domestic
pigeons has hardly varied at all from that of the wild type; while, on
the other hand, it is in exactly those respects, such as the relative
length of the beak and skull, the number of the vertebræ, and the number
of the tail-feathers, in which muscular exertion can have no important
influence, that the utmost amount of variation has taken place.
* * * * *
We have said that the following out of the properties exhibited by
physiological species would lead us into difficulties, and at this point
they begin to be obvious; for, if, as a result of spontaneous variation
and of selective breeding, the progeny of a common stock may become
separated into groups distinguished from one another by constant, not
sexual, morphological characters, it is clear that the physiological
definition of species is likely to clash with the morphological
definition. No one would hesitate to describe the pouter and the tumbler
as distinct species, if they were found fossil, or if their skins and
skeletons were imported, as those of exotic wild birds commonly
are--and, without doubt, if considered alone, they are good and distinct
morphological species. On the other hand, they are not physiological
species, for they are descended from a common stock, the rock-pigeon.
Under these circumstances, as it is admitted on all sides that races
occur in nature, how are we to know whether any apparently distinct
animals are really of different physiological species, or not, seeing
that the amount of morphological difference is no safe guide? Is there
any test of a physiological species? The usual answer of physiologists
is in the affirmative. It is said that such a test is to be found in the
phenomena of hybridization--in the results of crossing races as compared
with the results of crossing species.
So far as the evidence goes at present, individuals, of what are
certainly known to be mere races produced by selection, however distinct
they may appear to be, not only breed freely together, but the offspring
of such crossed races are also perfectly fertile with one another. Thus,
the spaniel and the greyhound, the dray-horse and the Arab, the pouter
and the tumbler, breed together with perfect freedom, and their
mongrels, if matched with other mongrels of the same kind, are equally
fertile.
On the other hand, there can be no doubt that the individuals of many
natural species are either absolutely infertile, if crossed with
individuals of other species, or, if they give rise to hybrid offspring,
the hybrids so produced are infertile when paired together. The horse
and the ass, for instance, if so crossed, give rise to the mule, and
there is no certain evidence of offspring ever having been produced by a
male and female mule. The unions of the rock-pigeon and the ring-pigeon
appear to be equally barren of result. Here, then, says the
physiologist, we have a means of distinguishing any two true species
from any two varieties. If a male and a female, selected from each
group, produce offspring, and that offspring is fertile with others
produced in the same way, the groups are races and not species. If, on
the other hand, no result ensues, or if the offspring are infertile with
others produced in the same way, they are true physiological species.
The test would be an admirable one, if, in the first place, it were
always practicable to apply it, and if, in the second, it always yielded
results susceptible of a definite interpretation. Unfortunately, in the
great majority of cases, this touchstone for species is wholly
inapplicable.
The constitution of many wild animals is so altered by confinement that
they will not even breed with their own females, so that the negative
results obtained from crosses are of no value, and the antipathy of wild
animals of different species for one another, or even of wild and tame
members of the same species, is ordinarily so great, that it is hopeless
to look for such unions in nature. The hermaphrodism of most plants, the
difficulty in the way of ensuring the absence of their own, or the
proper working of other pollen, are obstacles of no less magnitude in
applying the test to them. And in both animals and plants is superadded
the further difficulty, that experiments must be continued over a long
time for the purpose of ascertaining the fertility of the mongrel or
hybrid progeny, as well as of the first crosses from which they spring.
Not only do these great practical difficulties lie in the way of
applying the hybridization test, but even when this oracle can be
questioned, its replies are sometimes as doubtful as those of Delphi.
For example, cases are cited by Mr. Darwin, of plants which are more
fertile with the pollen of another species than with their own; and
there are others, such as certain _fuci_, whose male element will
fertilize the ovule of a plant of distinct species, while the males of
the latter species are ineffective with the females of the first. So
that, in the last-named instance, a physiologist, who should cross the
two species in one way, would decide that they were true species; while
another, who should cross them in the reverse way, would, with equal
justice, according to the rule, pronounce them to be mere races. Several
plants, which there is great reason to believe are mere varieties, are
almost sterile when crossed; while both animals and plants, which have
always been regarded by naturalists as of distinct species, turn out,
when the test is applied, to be perfectly fertile. Again, the sterility
or fertility of crosses seems to bear no relation to the structural
resemblances or differences of the members of any two groups. Mr. Darwin
has discussed this question with singular ability and circumspection,
and his conclusions are summed up as follows at page 276 of his work:--
"First crosses between forms sufficiently distinct to be
ranked as species, and their hybrids, are very generally,
but not universally, sterile. The sterility is of all
degrees, and is often so slight that the two most careful
experimentalists who have ever lived have come to
diametrically opposite conclusions in ranking forms by
this test. The sterility is innately variable in
individuals of the same species, and is eminently
susceptible of favourable and unfavourable conditions.
The degree of sterility does not strictly follow
systematic affinity, but is governed by several curious
and complex laws. It is generally different, and
sometimes widely different, in reciprocal crosses between
the same two species. It is not always equal in degree in
a first cross, and in the hybrid produced from this
cross.
"In the same manner as in grafting trees, the capacity of
one species or variety to take on another is incidental
on generally unknown differences in their vegetative
systems, so in crossing, the greater or less facility of
one species to unite with another is incidental on
unknown differences in their reproductive systems. There
is no more reason to think that species have been
specially endowed with various degrees of sterility to
prevent them crossing and breeding in nature, than to
think that trees have been specially endowed with various
and somewhat analogous degrees of difficulty in being
grafted together, in order to prevent them becoming
inarched in our forests.
"The sterility of first crosses between pure species,
which have their reproductive systems perfect, seems to
depend on several circumstances; in some cases largely on
the early death of the embryo. The sterility of hybrids
which have their reproductive systems imperfect, and
which have had this system and their whole organization
disturbed by being compounded of two distinct species,
seems closely allied to that sterility which so
frequently affects pure species when their natural
conditions of life have been disturbed. This view is
supported by a parallelism of another kind; namely, that
the crossing of forms only slightly different is
favourable to the vigour and fertility of the offspring;
and that slight changes in the conditions of life are
apparently favourable to the vigour and fertility of all
organic beings. It is not surprising that the degree of
difficulty in uniting two species, and the degree of
sterility of their hybrid offspring should generally
correspond, though due to distinct causes; for both
depend on the amount of difference of some kind between
the species which are crossed. Nor is it surprising that
the facility of effecting a first cross, the fertility of
hybrids produced from it, and the capacity of being
grafted together--though this latter capacity evidently
depends on widely different circumstances--should all run
to a certain extent parallel with the systematic affinity
of the forms which are subjected to experiment; for
systematic affinity attempts to express all kinds of
resemblance between all species.
"First crosses between forms known to be varieties, or
sufficiently alike to be considered as varieties, and
their mongrel offspring, are very generally, but not
quite universally, fertile. Nor is this nearly general
and perfect fertility surprising, when we remember how
liable we are to argue in a circle with respect to
varieties in a state of nature; and when we remember that
the greater number of varieties have been produced under
domestication by the selection of mere external
differences, and not of differences in the reproductive
system. In all other respects, excluding fertility, there
is a close general resemblance between hybrids and
mongrels" (pp. 276-8).
We fully agree with the general tenor of this weighty passage, but
forcible as are these arguments, and little as the value of fertility or
infertility as a test of species may be, it must not be forgotten that
the really important fact, so far as the inquiry into the origin of
species goes, is, that there are such things in nature as groups of
animals and of plants, whose members are incapable of fertile union with
those of other groups; and that there are such things as hybrids, which
are absolutely sterile when crossed with other hybrids. For if such
phenomena as these were exhibited by only two of those assemblages of
living objects, to which the name of species (whether it be used in its
physiological or in its morphological sense) is given, it would have to
be accounted for by any theory of the origin of species, and every
theory which could not account for it would be, so far, imperfect.
Up to this point we have been dealing with matters of fact, and the
statements which we have laid before the reader would, to the best of
our knowledge, be admitted to contain a fair exposition of what is at
present known respecting the essential properties of species, by all who
have studied the question. And whatever may be his theoretical views, no
naturalist will probably be disposed to demur to the following summary
of that exposition:--
Living beings, whether animals or plants, are divisible into multitudes
of distinctly definable kinds, which are morphological species. They are
also divisible into groups of individuals, which breed freely together,
tending to reproduce their like, and are physiological species.
Normally, resembling their parents, the offspring of members of these
species are still liable to vary, and the variation may be perpetuated
by selection, as a race, which race, in many cases, presents all the
characteristics of a morphological species. But it is not as yet proved
that a race ever exhibits, when crossed with another race of the same
species, those phenomena of hybridization which are exhibited by many
species when crossed with other species. On the other hand, not only is
it not proved that all species give rise to hybrids infertile _inter
se_, but there is much reason to believe that, in crossing, species
exhibit every gradation from perfect sterility to perfect fertility.
Such are the most essential characteristics of species. Even were man
not one of them--a member of the same system and subject to the same
laws--the question of their origin, their causal connexion, that is,
with the other phenomena of the universe, must have attracted his
attention, as soon as his intelligence had raised itself above the level
of his daily wants.
Indeed history relates that such was the case, and has embalmed for us
the speculations upon the origin of living beings, which were among the
earliest products of the dawning intellectual activity of man. In those
early days positive knowledge was not to be had, but the craving after
it needed, at all hazards, to be satisfied, and according to the
country, or the turn of thought of the speculator, the suggestion that
all living things arose from the mud of the Nile, from a primeval egg,
or from some more anthropomorphic agency, afforded a sufficient
resting-place for his curiosity. The myths of Paganism are as dead as
Osiris or Zeus, and the man who should revive them, in opposition to the
knowledge of our time, would be justly laughed to scorn; but the coeval
imaginations current among the rude inhabitants of Palestine, recorded
by writers whose very name and age are admitted by every scholar to be
unknown, have unfortunately not yet shared their fate, but, even at this
day, are regarded by nine-tenths of the civilized world as the
authoritative standard of fact and the criterion of the justice of
scientific conclusions, in all that relates to the origin of things,
and, among them, of species. In this nineteenth century, as at the dawn
of modern physical science, the cosmogony of the semi-barbarous Hebrew
is the incubus of the philosopher and the opprobrium of the orthodox.
Who shall number the patient and earnest seekers after truth from the
days of Galileo until now, whose lives have been embittered and their
good name blasted by the mistaken zeal of Bibliolaters? Who shall count
the host of weaker men whose sense of truth has been destroyed in the
effort to harmonize impossibilities--whose life has been wasted in the
attempt to force the generous new wine of science into the old bottles
of Judaism, compelled by the outcry of the same strong party?
It is true that if philosophers have suffered, their cause has been
amply avenged. Extinguished theologians lie about the cradle of every
science as the strangled snakes beside that of Hercules, and history
records that whenever science and dogmatism have been fairly opposed,
the latter has been forced to retire from the lists, bleeding and
crushed, if not annihilated; scotched, if not slain. But orthodoxy is
the Bourbon of the world of thought. It learns not, neither can it
forget; and though at present bewildered and afraid to move, it is as
willing as ever to insist that the first chapter of Genesis contains the
beginning and the end of sound science, and to visit with such petty
thunderbolts as its half-paralysed hands can hurl, those who refuse to
degrade nature to the level of primitive Judaism.
Philosophers, on the other hand, have no such aggressive tendencies.
With eyes fixed on the noble goal to which "per aspera et ardua" they
tend, they may, now and then, be stirred to momentary wrath by the
unnecessary obstacles with which the ignorant, or the malicious,
encumber, if they cannot bar, the difficult path; but why should their
souls be deeply vexed? The majesty of Fact is on their side, and the
elemental forms of matter are working for them. Not a star comes to the
meridian at its calculated time but testifies to the justice of their
methods--their beliefs are "one with the falling rain and with the
growing corn." By doubt they are established, and open inquiry is their
bosom friend. Such men have no fear of traditions however venerable, and
no respect for them when they become mischievous and obstructive; but
they have better than mere antiquarian business in hand, and if dogmas,
which ought to be fossil but are not, are not forced upon their notice,
they are too happy to treat them as non-existent.
* * * * *
The hypotheses respecting the origin of species, which profess to stand
upon a scientific basis, and, as such, alone demand serious attention,
are of two kinds. The one, the "special creation" hypothesis, presumes
every species to have originated from one or more stocks, these not
being the result of the modification of any other form of living
matter--or arising by natural agencies--but being produced, as such, by
a supernatural creative act.
The other, the so-called "transmutation" hypothesis, considers that all
existing species are the result of the modification of pre-existing
species and those of their predecessors, by agencies similar to those
which at the present day produce varieties and races, and therefore in
an altogether natural way; and it is a probable, though not a necessary
consequence of this hypothesis, that all living beings have arisen from
a single stock. With respect to the origin of this primitive stock or
stocks, the doctrine of the origin of species is obviously not
necessarily concerned. The transmutation hypothesis, for example, is
perfectly consistent either with the conception of a special creation of
the primitive germ, or with the supposition of its having arisen, as a
modification of inorganic matter, by natural causes.
The doctrine of special creation owes its existence very largely to the
supposed necessity of making science accord with the Hebrew cosmogony;
but it is curious to observe that, as the doctrine is at present
maintained by men of science, it is as hopelessly inconsistent with the
Hebrew view as any other hypothesis.
If there be any result which has come more clearly out of geological
investigation than another, it is, that the vast series of extinct
animals and plants is not divisible, as it was once supposed to be, into
distinct groups, separated by sharply marked boundaries. There are no
great gulfs between epochs and formations--no successive periods marked
by the appearance of plants, of water animals, and of land animals, _en
masse_. Every year adds to the list of links between what the older
geologists supposed to be widely separated epochs; witness the crags
linking the drift with the older tertiaries; the Maestricht beds linking
the tertiaries with the chalk; the St. Cassian beds exhibiting an
abundant fauna of mixed mesozoic and paleozoic types, in rocks of an
epoch once supposed to be eminently poor in life; witness, lastly, the
incessant disputes as to whether a given stratum shall be reckoned
devonian or carboniferous, silurian or devonian, cambrian or silurian.
This truth is further illustrated in a most interesting manner by the
impartial and highly competent testimony of M. Pictet, from whose
calculations of what percentage of the genera of animals existing in any
formation lived during the preceding formation, it results that in no
case is the proportion less than _one-third_, or 33 per cent. It is the
triassic formation, or the commencement of the mesozoic epoch, which has
received this smallest inheritance from preceding ages. The other
formations not uncommonly exhibit 60, 80, or even 94 per cent. of genera
in common with those whose remains are imbedded in their predecessor.
Not only is this true, but the subdivisions of each formation exhibit
new species characteristic of, and found only in, them, and in many
cases, as in the lias for example, the separate beds of these
subdivisions are distinguished by well marked and peculiar forms of
life. A section, a hundred feet thick, will exhibit at different heights
a dozen species of ammonite, none of which passes beyond its particular
zone of limestone or clay into the zone below it or into that above it;
so that those who adopt the doctrine of special creation must be
prepared to admit, that at intervals of time, corresponding with the
thickness of these beds, the Creator thought fit to interfere with the
natural course of events for the purpose of making a new ammonite. It is
not easy to transplant oneself into the frame of mind of those who can
accept such a conclusion as this, on any evidence, short of absolute
demonstration; and it is difficult to see what is to be gained by so
doing, since, as we have said, it is obvious that such a view of the
origin of living beings is utterly opposed to the Hebrew cosmogony.
Deserving no aid from the powerful arm of bibliolatry, then, does the
received form of the hypothesis of special creation derive any support
from science or sound logic? Assuredly not much. The arguments brought
forward in its favour all take one form: If species were not
supernaturally created, we cannot understand the facts _x_, or _y_, or
_z_; we cannot understand the structure of animals or plants, unless we
suppose they were contrived for special ends; we cannot understand the
structure of the eye, except by supposing it to have been made to see
with; we cannot understand instincts, unless we suppose animals to have
been miraculously endowed with them.
As a question of dialectics, it must be admitted that this sort of
reasoning is not very formidable to those who are not to be frightened
by consequences. It is an argumentum ad ignorantiam--take this
explanation or be ignorant. But suppose we prefer to admit our ignorance
rather than adopt a hypothesis at variance with all the teachings of
nature? Or suppose for a moment we admit the explanation, and then
seriously ask ourselves how much the wiser are we? what does the
explanation explain? Is it any more than a grandiloquent way of
announcing the fact, that we really know nothing about the matter? A
phenomenon is explained, when it is shown to be a case of some general
law of nature; but the supernatural interposition of the Creator can by
the nature of the case exemplify no law, and if species have really
arisen in this way, it is absurd to attempt to discuss their origin.
Or, lastly, let us ask ourselves whether any amount of evidence which
the nature of our faculties permits us to attain, can justify us in
asserting that any phenomenon is out of the reach of natural causation.
To this end it is obviously necessary that we should know all the
consequences to which all possible combinations, continued through
unlimited time, can give rise. If we knew these, and found none
competent to originate species, we should have good ground for denying
their origin by natural causation. Till we know them, any hypothesis is
better than one which involves us in such miserable presumption.
But the hypothesis of special creation is not only a mere specious mask
for our ignorance; its existence in Biology marks the youth and
imperfection of the science. For what is the history of every science
but the history of the elimination of the notion of creative, or other
interferences, with the natural order of the phenomena which are the
subject-matter of that science? When Astronomy was young "the morning
stars sang together for joy," and the planets were guided in their
courses by celestial hands. Now, the harmony of the stars has resolved
itself into gravitation according to the inverse squares of the
distances, and the orbits of the planets are deducible from the laws of
the forces which allow a schoolboy's stone to break a window. The
lightning was the angel of the Lord; but it has pleased Providence, in
these modern times, that science should make it the humble messenger of
man, and we know that every flash that skimmers about the horizon on a
summer's evening is determined by ascertainable conditions, and that its
direction and brightness might, if our knowledge of these were great
enough, have been calculated.
The solvency of great mercantile companies rests on the validity of the
laws, which have been ascertained to govern the seeming irregularity of
that human life which the moralist bewails as the most uncertain of
things; plague, pestilence, and famine are admitted, by all but fools,
to be the natural result of causes for the most part fully within human
control, and not the unavoidable tortures inflicted by wrathful
Omnipotence upon his helpless handiwork.
Harmonious order governing eternally continuous progress--the web and
woof of matter and force interweaving by slow degrees, without a broken
thread, that veil which lies between us and the Infinite--that universe
which alone we know, or can know;--such is the picture which science
draws of the world, and in proportion as any part of that picture is in
unison with the rest, so may we feel sure that it is rightly painted.
Shall Biology alone remain out of harmony with her sister sciences?
Such arguments against the hypothesis of the direct creation of species
as these are plainly enough deducible from general considerations, but
there are, in addition, phenomena exhibited by species themselves, and
yet not so much a part of their very essence as to have required earlier
mention, which are in the highest degree perplexing, if we adopt the
popularly accepted hypothesis. Such are the facts of distribution in
space and in time; the singular phenomena brought to light by the study
of development; the structural relations of species upon which our
systems of classification are founded; the great doctrines of
philosophical anatomy, such as that of homology, or of the community of
structural plan exhibited by large groups of species differing very
widely in their habits and functions.
The species of animals which inhabit the sea on opposite sides of the
isthmus of Panama are wholly distinct; the animals and plants which
inhabit islands are commonly distinct from those of the neighbouring
mainlands, and yet have a similarity of aspect. The mammals of the
latest tertiary epoch in the Old and New Worlds belong to the same
genera, or family groups, as those which now inhabit the same great
geographical area. The crocodilian reptiles which existed in the
earliest secondary epoch were similar in general structure to those now
living, but exhibit slight differences in their vertebræ, nasal
passages, and one or two other points. The guinea-pig has teeth which
are shed before it is born, and hence can never subserve the masticatory
purpose for which they seem contrived, and, in like manner, the female
dugong has tusks which never cut the gum. All the members of the same
great group run through similar conditions in their development, and all
their parts, in the adult state, are arranged according to the same
plan. Man is more like a gorilla than a gorilla is like a lemur. Such
are a few, taken at random, among the multitudes of similar facts which
modern research has established; but when the student seeks for an
explanation of them from the supporters of the received hypothesis of
the origin of species, the reply he receives is, in substance, of
oriental simplicity and brevity--"Mashallah! it so pleases God!" There
are different species on opposite sides of the isthmus of Panama,
because they were created different on the two sides. The pliocene
mammals are like the existing ones, because such was the plan of
creation; and we find rudimental organs and similarity of plan, because
it has pleased the Creator to set before himself a "divine exemplar or
archetype," and to copy it in his works; and somewhat ill, those who
hold this view imply, in some of them. That such verbal hocus-pocus
should be received as science will one day be regarded as evidence of
the low state of intelligence in the nineteenth century, just as we
amuse ourselves with the phraseology about Nature's abhorrence of a
vacuum, wherewith Torricelli's compatriots were satisfied to explain the
rise of water in a pump. And be it recollected that this sort of
satisfaction works not only negative but positive ill, by discouraging
inquiry, and so depriving man of the usufruct of one of the most fertile
fields of his great patrimony, Nature.
The objections to the doctrine of origin of species by special creation
which have been detailed, must have occurred with more or less force to
the mind of every one who has seriously and independently considered the
subject. It is therefore no wonder that, from time to time, this
hypothesis should have been met by counter hypotheses, all as well, and
some better, founded than itself; and it is curious to remark that the
inventors of the opposing views seem to have been led into them as much
by their knowledge of geology as by their acquaintance with biology. In
fact, when the mind has once admitted the conception of the gradual
production of the present physical state of our globe, by natural causes
operating through long ages of time, it will be little disposed to allow
that living beings have made their appearance in another way, and the
speculations of De Maillet and his successors are the natural complement
of Scilla's demonstration of the true nature of fossils.
A contemporary of Newton and of Leibnitz, sharing therefore in the
intellectual activity of the remarkable age which witnessed the birth of
modern physical science, Benoît de Maillet spent a long life as a
consular agent of the French Government in various Mediterranean ports.
For sixteen years, in fact, he held the office of Consul-General in
Egypt, and the wonderful phenomena offered by the valley of the Nile
appear to have strongly impressed his mind, to have directed his
attention to all facts of a similar order which came within his
observation, and to have led him to speculate on the origin of the
present condition of our globe and of its inhabitants. But, with all his
ardour for science, De Maillet seems to have hesitated to publish views
which, notwithstanding the ingenious attempts to reconcile them with the
Hebrew hypothesis contained in the preface to "Telliamed" (and which we
recommend for Mr. MacCausland's perusal), were hardly likely to be
received with favour by his contemporaries.
But a short time had elapsed since more than one of the great anatomists
and physicists of the Italian school had paid dearly for their
endeavours to dissipate some of the prevalent errors; and their
illustrious pupil, Harvey, the founder of modern physiology, had not
fared so well, in a country less oppressed by the benumbing influences
of theology, as to tempt any man to follow his example. Probably not
uninfluenced by these considerations, his Catholic majesty's
Consul-General for Egypt kept his theories to himself throughout a long
life, for "Telliamed," the only scientific work which is known to have
proceeded from his pen, was not printed till 1735, when its author had
reached the ripe age of seventy-nine; and though De Maillet lived three
years longer, his book was not given to the world before 1748. Even then
it was anonymous to those who were not in the secret of the anagrammatic
character of its title, and the preface and dedication are so worded as,
in case of necessity, to give the printer a fair chance of falling back
on the excuse that the work was intended for a mere jeu d'esprit.
The speculations of the supposititious Indian sage, though quite as
sound as those of many a "Mosaic Geology" which sells exceedingly well,
have no great value if we consider them by the light of modern science.
The waters are supposed to have originally covered up the whole globe;
to have deposited the rocky masses which compose its mountains by
processes comparable to those which are now forming mud, sand, and
shingle; and then to have gradually lowered their level, leaving the
spoils of the animal and vegetable inhabitants embedded in the strata.
As the dry land appeared, certain of the aquatic animals are supposed to
have taken to it, and to have become gradually adapted to terrestrial
and aerial modes of existence. But if we regard the general tenor and
style of the reasoning in relation to the state of knowledge of the day,
two circumstances appear very well worthy of remark. The first, that De
Maillet had a notion of the modifiability of living forms (though
without any precise information on the subject), and how such
modifiability might account for the origin of species; the second, that
he very clearly apprehended the great modern geological doctrine, so
strongly insisted upon by Hutton, and so ably and comprehensively
expounded by Lyell, that we must look to existing causes for the
explanation of past geological events. The following passage of the
preface indeed, in which De Maillet is supposed to speak of the Indian
philosopher Telliamed, his _alter ego_, might have been written by the
most philosophical uniformitarian of the present day.
"Ce qu'il y a d'étonnant, est que pour arriver à ces
connoissances il semble avoir perverti l'ordre naturel,
puisqu'au lieu de s'attacher d'abord à rechercher
l'origine de notre globe il a commencé par travailler à
s'instruire de la nature. Mais à l'entendre, ce
renversement de l'ordre a été pour lui l'effet d'un génie
favorable qui l'a conduit pas à pas et comme par la main
aux découvertes les plus sublimes. C'est en décomposant
la substance de ce globe par une anatomie exacte de
toutes ses parties qu'il a premièrement appris de quelles
matières il était composé et quels arrangemens ces mêmes
matières observaient entre elles. Ces lumières jointes à
l'esprit de comparaison toujours nécessaire à quiconque
entreprend de percer les voiles dont la nature aime à se
cacher, ont servi de guide à notre philosophe pour
parvenir à des connoissances plus intéressantes. Par la
matière et l'arrangement de ces compositions il prétend
avoir reconnu quelle est la véritable origine de ce globe
que nous habitons, comment et par qui il a été
formé."--(Pp. xix. xx.)
But De Maillet was before his age, and as could hardly fail to happen to
one who speculated on a zoological and botanical question before
Linnæus, and on a physiological problem before Haller, he fell into
great errors here and there; and hence, perhaps, the general neglect of
his work. Robinet's speculations are rather behind than in advance of
those of De Maillet, and though Linnæus may have played with the
hypothesis of transmutation, it obtained no serious support until
Lamarck adopted it, and advocated it with great ability in his
"Philosophie Zoologique."
Impelled towards the hypothesis of the transmutation of species, partly
by his general cosmological and geological views; partly by the
conception of a graduated, though irregularly branching scale of being,
which had arisen out of his profound study of plants and of the lower
forms of animal life, Lamarck, whose general line of thought often
closely resembles that of De Maillet, made a great advance upon the
crude and merely speculative manner in which that writer deals with the
question of the origin of living beings, by endeavouring to find
physical causes competent to effect that change of one species into
another which De Maillet had only supposed to occur. And Lamarck
conceived that he had found in nature such causes, amply sufficient for
the purpose in view. It is a physiological fact, he says, that organs
are increased in size by action, atrophied by inaction; it is another
physiological fact that modifications produced are transmissible to
offspring. Change the actions of an animal, therefore, and you will
change its structure, by increasing the development of the parts newly
brought into use and by the diminution of those less used; but by
altering the circumstances which surround it you will alter its actions,
and hence, in the long run, change of circumstance must produce change
of organization. All the species of animals, therefore, are in Lamarck's
view the result of the indirect action of changes of circumstance upon
those primitive germs which he considered to have originally arisen, by
spontaneous generation, within the waters of the globe. It is curious,
however, that Lamarck should insist so strongly[64] as he has done,
that circumstances never in any degree directly modify the form or the
organization of animals, but only operate by changing their wants, and
consequently their actions; for he thereby brings upon himself the
obvious question, how, then, do plants, which cannot be said to have
wants or actions, become modified? To this he replies, that they are
modified by the changes in their nutritive processes, which are effected
by changing circumstances; and it does not seem to have occurred to him
that such changes might be as well supposed to take place among animals.
When we have said that Lamarck felt that mere speculation was not the
way to arrive at the origin of species, but that it was necessary in
order to the establishment of any sound theory on the subject, to
discover by observation or otherwise, some _vera causa_, competent to
give rise to them; that he affirmed the true order of classification to
coincide with the order of their development one from another; that he
insisted on the necessity of allowing sufficient time, very strongly;
and that all the varieties of instinct and reason were traced back by
him to the same cause as that which has given rise to species, we have
enumerated his chief contributions to the advance of the question. On
the other hand, from his ignorance of any power in nature competent to
modify the structure of animals, except the development of parts, or
atrophy of them, in consequence of a change of needs, Lamarck was led to
attach infinitely greater weight than it deserves to this agency, and
the absurdities into which he was led have met with deserved
condemnation. Of the struggle for existence, on which as we shall see
Mr. Darwin lays such great stress, he had no conception; indeed, he
doubts whether there really are such things as extinct species, unless
they be such large animals as may have met their death at the hands of
man; and so little does he dream of there being any other destructive
causes at work, that, in discussing the possible existence of fossil
shells, he asks, "Pourquoi d'ailleurs seroient-ils perdues dès que
l'homme n'a pu opérer leur destruction?" ("Phil. Zool.," vol. i. p. 77).
Of the influence of selection Lamarck has as little notion, and he makes
no use of the wonderful phenomena which are exhibited by domesticated
animals, and illustrate its powers. The vast influence of Cuvier was
employed against the Lamarckian views, and as the untenability of some
of his conclusions was easily shown, his doctrines sank under the
opprobrium of scientific as well as of theological heterodoxy. Nor have
the efforts made of late years to revive them, tended to re-establish
their credit in the minds of sound thinkers acquainted with the facts of
the case; indeed it may be doubted whether Lamarck has not suffered more
from his friends than from his foes.
Two years ago, in fact, though we venture to question if even the
strongest supporters of the special creation hypothesis had not, now and
then, an uneasy consciousness that all was not right, their position
seemed more impregnable than ever, if not by its own inherent strength,
at any rate by the obvious failure of all the attempts which had been
made to carry it. On the other hand, however much the few, who thought
deeply on the question of species, might be repelled by the generally
received dogmas, they saw no way of escaping from them, save by the
adoption of suppositions, so little justified by experiment or by
observation, as to be at least equally distasteful; The choice lay
between two absurdities and a middle condition of uneasy scepticism;
which last, however unpleasant and unsatisfactory, was obviously the
only justifiable state of mind under the circumstances.
Such being the general ferment in the minds of naturalists, it is no
wonder that they mustered strong in the rooms of the Linnæan Society, on
the first of July of the year 1858, to hear two papers by authors living
on opposite sides of the globe, working out their results independently,
and yet professing to have discovered one and the same solution of all
the problems connected with species. The one of these authors was an
able naturalist, Mr. Wallace, who had been employed for some years in
studying the productions of the islands of the Indian Archipelago, and
who had forwarded a memoir embodying his views to Mr. Darwin for
communication to the Linnæan Society. On perusing the essay Mr. Darwin
was not a little surprised to find that it embodied some of the leading
ideas of a great work which he had been preparing for twenty years, and
parts of which, containing a development of the very same views, had
been perused by his private friends fifteen or sixteen years before.
Perplexed in what manner to do full justice both to his friend and to
himself, Mr. Darwin placed the matter in the hands of Dr. Hooker and Sir
Charles Lyell, by whose advice he communicated a brief abstract of his
own views to the Linnæan Society, at the same time that Mr. Wallace's
paper was read. Of that abstract, the work on the "Origin of Species" is
an enlargement, but a complete statement of Mr. Darwin's doctrine is
looked for in the large and well-illustrated work which he is said to be
preparing for publication.[65]
* * * * *
The Darwinian hypothesis has the merit of being eminently simple and
comprehensible in principle, and its essential positions may be stated
in a very few words: all species have been produced by the development
of varieties from common stocks, by the conversion of these, first into
permanent races and then into new species, by the process of _natural
selection_, which process is essentially identical with that artificial
selection by which man has originated the races of domestic animals--the
_struggle for existence_ taking the place of man, and exerting, in the
case of natural selection, that selective action which he performs in
artificial selection.
The evidence brought forward by Mr. Darwin in support of his hypothesis
is of three kinds. First, he endeavours to prove that species may be
originated by selection; secondly, he attempts to show that natural
causes are competent to exert selection; and thirdly, he tries to prove
that the most remarkable and apparently anomalous phenomena exhibited by
the distribution, development, and mutual relations of species, can be
shown to be deducible from the general doctrine of their origin, which
he propounds, combined with the known facts of geological change; and
that, even if not all these phenomena are at present explicable by it,
none are necessarily inconsistent with it.
There cannot be a doubt that the method of inquiry which Mr. Darwin has
adopted is not only rigorously in accordance with the canons of
scientific logic, but that it is the only adequate method. Critics
exclusively trained in classics or in mathematics, who have never
determined a scientific fact in their lives by induction from experiment
or observation, prate learnedly about Mr. Darwin's method, which is not
inductive enough, not Baconian enough, forsooth, for them. But even if
practical acquaintance with the process of scientific investigation is
denied them, they may learn, by the perusal of Mr. Mill's admirable
chapter "On the Deductive Method," that there are multitudes of
scientific inquiries, in which the method of pure induction helps the
investigator but a very little way.
"The mode of investigation" (says Mr. Mill) "which from the proved
inapplicability of direct methods of observation and experiment remains
to us as the main source of the knowledge we possess, or can acquire,
respecting the conditions and laws of recurrence of the more complex
phenomena, is called, in its most general expression, the deductive
method, and consists of three operations: the first, one of direct
induction; the second, of ratiocination; and the third, of
verification."
Now, the conditions which have determined the existence of species are
not only exceedingly complex, but, so far as the great majority of them
are concerned, are necessarily beyond our cognisance. But what Mr.
Darwin has attempted to do is in exact accordance with the rule laid
down by Mr. Mill; he has endeavoured to determine certain great facts
inductively, by observation and experiment; he has then reasoned from
the data thus furnished; and lastly, he has tested the validity of his
ratiocination by comparing his deductions with the observed facts of
nature. Inductively, Mr. Darwin endeavours to prove that species arise
in a given way. Deductively, he desires to show that, if they arise in
that way, the facts of distribution, development, classification, &c.,
may be accounted for, _i.e._ may be deduced from their mode of origin,
combined with admitted changes in physical geography and climate, during
an indefinite period. And this explanation, or coincidence of observed
with deduced facts, is, so far as it extends, a verification of the
Darwinian view.
There is no fault to be found with Mr. Darwin's method, then; but it is
another question whether he has fulfilled all the conditions imposed by
that method. Is it satisfactorily proved, in fact, that species may be
originated by selection? that there is such a thing as natural
selection? that none of the phenomena exhibited by species are
inconsistent with the origin of species in this way? If these questions
can be answered in the affirmative, Mr. Darwin's view steps out of the
ranks of hypotheses into those of proved theories; but so long as the
evidence at present adduced falls short of enforcing that affirmation,
so long, to our minds, must the new doctrine be content to remain among
the former--an extremely valuable, and in the highest degree probable,
doctrine, indeed the only extant hypothesis which is worth anything in a
scientific point of view; but still a hypothesis, and not yet the theory
of species.
After much consideration, and with assuredly no bias against Mr.
Darwin's views, it is our clear conviction that, as the evidence stands,
it is not absolutely proven that a group of animals, having all the
characters exhibited by species in nature, has ever been originated by
selection, whether artificial or natural. Groups having the
morphological character of species, distinct and permanent races in
fact, have been so produced over and over again; but there is no
positive evidence at present that any group of animals has, by variation
and selective breeding, given rise to another group which was even in
the least degree infertile with the first. Mr. Darwin is perfectly aware
of this weak point, and brings forward a multitude of ingenious and
important arguments to diminish the force of the objection. We admit the
value of these arguments to their fullest extent; nay, we will go so far
as to express our belief that experiments, conducted by a skilful
physiologist, would very probably obtain the desired production of
mutually more or less infertile breeds from a common stock, in a
comparatively few years; but still, as the case stands at present, this
"little rift within the lute" is not to be disguised nor overlooked.
In the remainder of Mr. Darwin's argument our own private ingenuity has
not hitherto enabled us to pick holes of any great importance; and
judging by what we hear and read, other adventurers in the same field do
not seem to have been much more fortunate. It has been urged, for
instance, that in his chapters on the struggle for existence and on
natural selection, Mr. Darwin does not so much prove that natural
selection does occur, as that it must occur; but, in fact, no other sort
of demonstration is attainable. A race does not attract our attention in
nature until it has, in all probability, existed for a considerable
time, and then it is too late to inquire into the conditions of its
origin. Again, it is said that there is no real analogy between the
selection which takes place under domestication, by human influence, and
any operation which can be effected by nature, for man interferes
intelligently. Reduced to its elements, this argument implies that an
effect produced with trouble by an intelligent agent must, _à fortiori_
be more troublesome, if not impossible, to an unintelligent agent. Even
putting aside the question whether nature, acting as she does according
to definite and invariable laws, can be rightly called an unintelligent
agent, such a position as this is wholly untenable. Mix salt and sand,
and it shall puzzle the wisest of men with his mere natural appliances
to separate all the grains of sand from all the grains of salt; but a
shower of rain will effect the same object in ten minutes. And so while
man may find it tax all his intelligence to separate any variety which
arises, and to breed selectively from it, the destructive agencies
incessantly at work in nature, if they find one variety to be more
soluble in circumstances than the other, will inevitably in the long run
eliminate it.
A frequent and a just objection to the Lamarckian hypothesis of the
transmutation of species is based upon the absence of transitional forms
between many species. But against the Darwinian hypothesis this argument
has no force. Indeed, one of the most valuable and suggestive parts of
Mr. Darwin's work is that in which he proves, that the frequent absence
of transitions is a necessary consequence of his doctrine, and that the
stock whence two or more species have sprung, need in no respect be
intermediate between these species. If any two species have arisen from
a common stock in the same way as the carrier and the pouter, say, have
arisen from the rock-pigeon, then the common stock of these two species
need be no more intermediate between the two than the rock-pigeon is
between the carrier and pouter. Clearly appreciate the force of this
analogy, and all the arguments against the origin of species by
selection, based on the absence of transitional forms, fall to the
ground. And Mr. Darwin's position might, we think, have been even
stronger than it is if he had not embarrassed himself with the aphorism,
"_Natura non facit saltum_," which turns up so often in his pages. We
believe, as we have said above, that nature does make jumps now and
then, and a recognition of the fact is of no small importance in
disposing of many minor objections to the doctrine of transmutation.
But we must pause. The discussion of Mr. Darwin's arguments in detail
would lead us far beyond the limits within which we proposed, at
starting, to confine this article. Our object has been attained if we
have given an intelligible, however brief, account of the established
facts connected with species, and of the relation of the explanation of
those facts offered by Mr. Darwin to the theoretical views held by his
predecessors and his contemporaries, and, above all, to the requirements
of scientific logic. We have ventured to point out that it does not, as
yet, satisfy all those requirements; but we do not hesitate to assert
that it is as superior to any preceding or contemporary hypothesis, in
the extent of observational and experimental basis on which it rests, in
its rigorously scientific method, and in its power of explaining
biological phenomena, as was the hypothesis of Copernicus to the
speculations of Ptolemy. But the planetary orbits turned out to be not
quite circular after all, and grand as was the service Copernicus
rendered to science, Kepler and Newton had to come after him. What if
the orbit of Darwinism should be a little too circular? what if species
should offer residual phenomena here and there, not explicable by
natural selection? Twenty years hence naturalists may be in a position
to say whether this is, or is not, the case; but in either event they
will owe the author of "The Origin of Species" an immense debt of
gratitude. We should leave a very wrong impression on the reader's mind
if we permitted him to suppose that the value of that work depends
wholly on the ultimate justification of the theoretical views which it
contains. On the contrary, if they were disproved to-morrow, the book
would still be the best of its kind--the most compendious statement of
well-sifted facts bearing on the doctrine of species that has ever
appeared. The chapters on Variation, on the Struggle for Existence, on
Instinct, on Hybridism, on the Imperfection of the Geological Record, on
Geographical Distribution, have not only no equals, but, so far as our
knowledge goes, no competitors, within the range of biological
literature. And viewed as a whole, we do not believe that, since the
publication of Von Baer's Researches on Development, thirty years ago,
any work has appeared calculated to exert so large an influence, not
only on the future of Biology, but in extending the domination of
Science over regions of thought into which she has, as yet, hardly
penetrated.
FOOTNOTES:
[62] "On the Osteology of the Chimpanzees and Orangs." Transactions of
the Zoological Society, 1858.
[63] Colonel Humphreys' statements are exceedingly explicit on this
point:--"When an Ancon ewe is impregnated by a common ram the increase
resembles wholly either the ewe or the ram. The increase of the common
ewe impregnated by an Ancon ram follows entirely the one or the other,
without blending any of the distinguishing and essential peculiarities
of both. Frequent instances have happened where common ewes have had
twins by Ancon rams, when one exhibited the complete marks and features
of the ewe, the other of the ram. The contrast has been rendered
singularly striking, when one short-legged and one long-legged lamb,
produced at a birth, have been seen sucking the dam at the same
time."--Philosophical Transactions, 1813, Pt. I. pp. 89, 90.
[64] See Phil. Zoologique, vol. i. p. 222, _et seq._
[65] The reader will remember that Huxley was writing in 1860.
XIV
THE DARWINIAN HYPOTHESIS.
DARWIN ON THE ORIGIN OF SPECIES
There is a growing immensity in the speculations of science to which no
human thing or thought at this day is comparable. Apart from the results
which science brings us home and securely harvests, there is an
expansive force and latitude in its tentative efforts, which lifts us
out of ourselves and transfigures our mortality. We may have a
preference for moral themes, like the Homeric sage, who had seen and
known much:--
"Cities of men
And manners, climates, councils, governments;"
yet we must end by confessing that
"The windy ways of men
Are but dust which rises up
And is lightly laid again,"
in comparison with the work of nature, to which science testifies, but
which has no boundaries in time or space to which science can
approximate.
There is something altogether out of the reach of science, and yet the
compass of science is practically illimitable. Hence it is that from
time to time we are startled and perplexed by theories which have no
parallel in the contracted moral world; for the generalizations of
science sweep on in ever-widening circles, and more aspiring flights,
though a limitless creation. While astronomy, with its telescope, ranges
beyond the known stars, and physiology, with its microscope, is
subdividing infinite minutiæ, we may expect that our historic centuries
may be treated as inadequate counters in the history of the planet on
which we are placed. We must expect new conceptions of the nature and
relations of its denizens, as science acquires the materials for fresh
generalizations; nor have we occasion for alarms if a highly advanced
knowledge, like that of the eminent Naturalist before us, confronts us
with an hypothesis as vast as it is novel. This hypothesis may or may
not be sustainable hereafter; it may give way to something else, and
higher science may reverse what science has here built up with so much
skill and patience, but its sufficiency must be tried by the tests of
science _alone_, if we are to maintain our position as the heirs of
Bacon and the acquitters of Galileo. We must weigh this hypothesis
strictly in the controversy which is coming, by the only tests which are
appropriate, and by no others whatsoever.
The hypothesis to which we point, and of which the present work of Mr.
Darwin is but the preliminary outline, may be stated in his own language
as follows:--"_Species originated by means of natural selection, or
through the preservation of the favoured races in the struggle for
life_." To render this thesis intelligible, it is necessary to interpret
its terms. In the first place, what is a species? The question is a
simple one, but the right answer to it is hard to find, even if we
appeal to those who should know most about it. It is all those animals
or plants which have descended from a single pair of parents; it is the
smallest distinctly definable group of living organisms; it is an
eternal and immutable entity; it is a mere abstraction of the human
intellect having no existence in nature. Such are a few of the
significations attached to this simple word which may be culled from
authoritative sources; and if, leaving terms and theoretical subtleties
aside, we turn to facts and endeavour to gather a meaning for ourselves,
by studying the things to which, in practice, the name of species is
applied, it profits us little. For practice varies as much as theory.
Let the botanist or the zoologist examine and describe the productions
of a country, and one will pretty certainly disagree with the other as
to the number, limits, and definitions of the species into which he
groups the very same things. In these islands we are in the habit of
regarding mankind as of one species, but a fortnight's steam will land
us in a country where divines and savans, for once in agreement, vie
with one another in loudness of assertion, if not in cogency of proof,
that men are of different species; and, more particularly, that the
species negro is so distinct from our own that the Ten Commandments have
actually no reference to him. Even in the calm region of entomology,
where, if anywhere in this sinful world, passion and prejudice should
fail to stir the mind, one learned coleopterist will fill ten attractive
volumes with descriptions of species of beetles, nine-tenths of which
are immediately declared by his brother beetle-mongers to be no species
at all.
The truth is that the number of distinguishable living creatures almost
surpasses imagination. At least a hundred thousand such kinds of insects
alone have been described and may be identified in collections, and the
number of separable kinds of living things is under estimated at half a
million. Seeing that most of these obvious kinds have their accidental
varieties, and that they often shade into others by imperceptible
degrees, it may well be imagined that the task of distinguishing between
what is permanent and what fleeting, what is a species and what a mere
variety, is sufficiently formidable.
But is it not possible to apply a test whereby a true species may be
known from a mere variety? Is there no criterion of species? Great
authorities affirm that there is--that the unions of members of the same
species are always fertile, while those of distinct species are either
sterile, or their offspring, called hybrids, are so. It is affirmed not
only that this is an experimental fact, but that it is a provision for
the preservation of the purity of species. Such a criterion as this
would be invaluable; but, unfortunately, not only is it not obvious how
to apply it in the great majority of cases in which its aid is needed,
but its general validity is stoutly denied. The Hon. and Rev. Mr.
Herbert, a most trustworthy authority, not only asserts as the result of
his own observations and experiments that many hybrids are quite as
fertile as the parent species, but he goes so far as to assert that the
particular plant _Crinum capense_ is much more fertile when crossed by a
distinct species than when fertilised by its proper pollen! On the other
hand the famous Gaertner, though he took the greatest pains to cross the
primrose and cowslip, succeeded only once or twice in several years; and
yet it is a well-established fact that the primrose and the cowslip are
only varieties of the same kind of plant. Again, such cases as the
following are well established. The female of species A if crossed with
the male of species B is fertile, but if the female of B is crossed with
the male of A, she remains barren. Facts of this kind destroy the value
of the supposed criterion.
If, weary of the endless difficulties involved in the determination of
species, the investigator, contenting himself with the rough practical
distinction of separable kinds, endeavours to study them as they occur
in nature--to ascertain their relations to the conditions which surround
them, their mutual harmonies and discordances of structure, the bond of
union of their parts and their past history, he finds himself, according
to the received notions, in a mighty maze, and with, at most, the
dimmest adumbration of a plan. If he starts with any one clear
conviction, it is that every part of a living creature is cunningly
adapted to some special use in its life. Has not his Paley told him that
that seemingly useless organ, the spleen, is beautifully adjusted as so
much packing between the other organs? And yet, at the outset of his
studies, he finds that no adaptive reason whatsoever can be given for
one-half of the peculiarities of vegetable structure; he also discovers
rudimentary teeth, which are never used, in the gums of the young calf
and in those of the foetal whale; insects which never bite have
rudimental jaws, and others which never fly have rudimental wings;
naturally blind creatures have rudimental eyes; and the halt have
rudimentary limbs. So, again, no animal or plant puts on its perfect
form at once, but all have to start from the same point, however various
the course which each has to pursue. Not only men and horses, and cats
and dogs, lobsters and beetles, periwinkles and mussels, but even the
very sponges and animalcules commence their existence under forms which
are essentially undistinguishable; and this is true of all the infinite
variety of plants. Nay, more, all living beings march side by side along
the high road of development, and separate the later the more like they
are; like people leaving church, who all go down the aisle, but having
reached the door some turn into the parsonage, others go down the
village, and others part only in the next parish. A man in his
development runs for a little while parallel with, though never passing
through, the form of the meanest worm, then travels for a space beside
the fish, then journeys along with the bird and the reptile for his
fellow travellers; and only at last, after a brief companionship with
the highest of the four-footed and four-handed world, rises into the
dignity of pure manhood. No competent thinker of the present day dreams
of explaining these indubitable facts by the notion of the existence of
unknown and undiscoverable adaptations to purpose. And we would remind
those who, ignorant of the facts, must be moved by authority, that no
one has asserted the incompetence of the doctrine of final causes, in
its application to physiology and anatomy, more strongly than our own
eminent anatomist, Professor Owen, who, speaking of such cases, says
(_On the Nature of Limbs_, pp. 39, 40): "I think it will be obvious that
the principle of final adaptations fails to satisfy all the conditions
of the problem."
But, if the doctrine of final causes will not help us to comprehend the
anomalies of living structure, the principle of adaptation must surely
lead us to understand why certain living beings are found in certain
regions of the world and not in others. The palm, as we know, will not
grow in our climate, nor the oak in Greenland. The white bear cannot
live where the tiger thrives, nor _vice versâ_, and the more the natural
habits of animal and vegetable species are examined, the more do they
seem, on the whole, limited to particular provinces. But when we look
into the facts established by the study of the geographical distribution
of animals and plants it seems utterly hopeless to attempt to
understand the strange and apparently capricious relations which they
exhibit. One would be inclined to suppose _à priori_ that every country
must be naturally peopled by those animals that are fittest to live and
thrive in it. And yet how, on this hypothesis, are we to account for the
absence of cattle in the Pampas of South America when those parts of the
New World were discovered? It is not that they were unfit for cattle,
for millions of cattle now run wild there; and the like holds good of
Australia and New Zealand. It is a curious circumstance, in fact, that
the animals and plants of the Northern Hemisphere are not only as well
adapted to live in the Southern Hemisphere as its own autochthones, but
are in many cases absolutely better adapted, and so overrun and
extirpate the aborigines. Clearly, therefore, the species which
naturally inhabit a country are not necessarily the best adapted to its
climate and other conditions. The inhabitants of islands are often
distinct from any other known species of animal or plants (witness our
recent examples from the work of Sir Emerson Tennent, on Ceylon), and
yet they have almost always a sort of general family resemblance to the
animals and plants of the nearest mainland. On the other hand, there is
hardly a species of fish, shell, or crab common to the opposite sides of
the narrow isthmus of Panama. Wherever we look, then, living nature
offers us riddles of difficult solution, if we suppose that what we see
is all that can be known of it.
But our knowledge of life is not confined to the existing world.
Whatever their minor differences, geologists are agreed as to the vast
thickness of the accumulated strata which compose the visible part of
our earth, and the inconceivable immensity of the time of whose lapse
they are the imperfect, but the only accessible witnesses. Now,
throughout the greater part of this long series of stratified rocks are
scattered, sometimes very abundantly, multitudes of organic remains, the
fossilised exuviæ of animals and plants which lived and died while the
mud of which the rocks are formed was yet soft ooze, and could receive
and bury them. It would be a great error to suppose that these organic
remains were fragmentary relics. Our museums exhibit fossil shells of
immeasurable antiquity, as perfect as the day they were formed, whole
skeletons without a limb disturbed--nay, the changed flesh, the
developing embryos, and even the very footsteps of primæval organisms.
Thus the naturalist finds in the bowels of the earth species as well
defined as, and in some groups of animals more numerous than, those that
breathe the upper air. But, singularly enough, the majority of these
entombed species are wholly distinct from those that now live. Nor is
this unlikeness without its rule and order. As a broad fact, the further
we go back in time the less the buried species are like existing forms;
and the further apart the sets of extinct creatures are the less they
are like one another. In other words, there has been a regular
succession of living beings, each younger set being in a very broad and
general sense somewhat more like those which now live.
It was once supposed that this succession had been the result of vast
successive catastrophes, destructions, and re-creations _en masse_; but
catastrophes are now almost eliminated from geological, or at least
paleontological speculation; and it is admitted on all hands that the
seeming breaks in the chain of being are not absolute, but only relative
to our imperfect knowledge; that species have replaced species, not in
assemblages, but one by one; and that, if it were possible to have all
the phenomena of the past presented to us, the convenient epochs and
formations of the geologist, though having a certain distinctness, would
fade into one another with limits as undefinable as those of the
distinct and yet separable colours of the solar spectrum.
Such is a brief summary of the main truths which have been established
concerning species. Are these truths ultimate and irresolvable facts, or
are their complexities and perplexities the mere expressions of a higher
law?
A large number of persons practically assume the former position to be
correct. They believe that the writer of the Pentateuch was empowered
and commissioned to teach us scientific as well as other truth, that the
account we find there of the creation of living things is simply and
literally correct, and that anything which seems to contradict it is, by
the nature of the case, false. All the phenomena which have been
detailed are, on this view, the immediate product of a creative fiat and
consequently are out of the domain of science altogether.
Whether this view prove ultimately to be true or false, it is, at any
rate, not at present supported by what is commonly regarded as logical
proof, even if it be capable of discussion by reason; and hence we
consider ourselves at liberty to pass it by, and to turn to those views
which profess to rest on a scientific basis only, and therefore admit of
being argued to their consequences. And we do this with the less
hesitation as it so happens that those persons who are practically
conversant with the facts of the case (plainly a considerable advantage)
have always thought fit to range themselves under the latter category.
The majority of these competent persons have up to the present time
maintained two positions,--the first, that every species is, within
certain defined or definable limits, fixed and incapable of
modification; the second, that every species was originally produced by
a distinct creative act. The second position is obviously incapable of
proof or disproof, the direct operations of the Creator not being
subjects of science; and it must therefore be regarded as a corollary
from the first, the truth or falsehood of which is a matter of evidence.
Most persons imagine that the arguments in favour of it are
overwhelming; but to some few minds, and these, it must be confessed,
intellects of no small power and grasp of knowledge, they have not
brought conviction. Among these minds that of the famous naturalist
Lamarck, who possessed a greater acquaintance with the lower forms of
life than any man of his day, Cuvier not excepted, and was a good
botanist to boot, occupies a prominent place.
Two facts appear to have strongly affected the course of thought of this
remarkable man--the one, that finer or stronger links of affinity
connect all living beings with one another, and that thus the highest
creature grades by multitudinous steps into the lowest; the other, that
an organ may be developed in particular directions by exerting itself
in particular ways, and that modifications once induced may be
transmitted and become hereditary. Putting these facts together, Lamarck
endeavoured to account for the first by the operation of the second.
Place an animal in new circumstances, says he, and its needs will be
altered; the new needs will create new desires, and the attempt to
gratify such desires will result in an appropriate modification of the
organs exerted. Make a man a blacksmith, and his brachial muscles will
develope in accordance with the demands made upon them, and in like
manner, says Lamarck, "the efforts of some shortnecked bird to catch
fish without wetting himself have, with time and perseverance, given
rise to all our herons and long-necked waders."
The Lamarckian hypothesis has long since been justly condemned, and it
is the established practice for every tyro to raise his heel against the
carcass of the dead lion. But it is rarely either wise or instructive to
treat even the errors of a really great man with mere ridicule, and in
the present case the logical form of the doctrine stands on a very
different footing from its substance.
If species have really arisen by the operation of natural conditions, we
ought to be able to find those conditions now at work; we ought to be
able to discover in nature some power adequate to modify any given kind
of animal or plant in such a manner as to give rise to another kind,
which would be admitted by naturalists as a distinct species. Lamarck
imagined that he had discovered this _vera causa_ in the admitted facts
that some organs may be modified by exercise; and that modifications,
once produced, are capable of hereditary transmission. It does not seem
to have occurred to him to inquire whether there is any reason to
believe that there are any limits to the amount of modification
producible, or to ask how long an animal is likely to endeavour to
gratify an impossible desire. The bird, in our example, would surely
have renounced fish dinners long before it had produced the least effect
on leg or neck.
Since Lamarck's time almost all competent naturalists have left
speculations on the origin of species to such dreamers as the author of
the _Vestiges_, by whose well-intentioned efforts the Lamarckian theory
received its final condemnation in the minds of all sound thinkers.
Notwithstanding this silence, however, the transmutation theory, as it
has been called, has been a "skeleton in the closet" to many an honest
zoologist and botanist who had a soul above the mere naming of dried
plants and skins. Surely, has such an one thought, nature is a mighty
and consistent whole, and the providential order established in the
world of life must, if we could only see it rightly, be consistent with
that dominant over the multiform shapes of brute matter. But what is the
history of astronomy, of all the branches of physics, of chemistry, of
medicine, but a narration of the steps by which the human mind has been
compelled, often sorely against its will, to recognize the operation of
secondary causes in events where ignorance beheld an immediate
intervention of a higher power? And when we know that living things are
formed of the same elements as the inorganic world, that they act and
react upon it, bound by a thousand ties of natural piety, is it
probable, nay is it possible, that they, and they alone, should have no
order in their seeming disorder, no unity in their seeming multiplicity,
should suffer no explanation by the discovery of some central and
sublime law of mutual connexion?
Questions of this kind have assuredly often arisen, but it might have
been long before they received such expression as would have commanded
the respect and attention of the scientific world, had it not been for
the publication of the work which prompted this article. Its author, Mr.
Darwin, inheritor of a once celebrated name, won his spurs in science
when most of those now distinguished were young men, and has for the
last 20 years held a place in the front ranks of British philosophers.
After a circumnavigatory voyage, undertaken solely for the love of his
science, Mr. Darwin published a series of researches which at once
arrested the attention of naturalists and geologists; his
generalizations have since received ample confirmation, and now command
universal assent, nor is it questionable that they have had the most
important influence on the progress of science. More recently Mr.
Darwin, with a versatility which is among the rarest of gifts, turned
his attention to a most difficult question of zoology and minute
anatomy; and no living naturalist and anatomist has published a better
monograph than that which resulted from his labours. Such a man, at all
events, has not entered the sanctuary with unwashed hands, and when he
lays before us the results of 20 years' investigation and reflection we
must listen even though we be disposed to strike. But, in reading his
work it must be confessed that the attention which might at first be
dutifully, soon becomes willingly, given, so clear is the author's
thought, so outspoken his conviction, so honest and fair the candid
expression of his doubts. Those who would judge the book must read it;
we shall endeavour only to make its line of argument and its
philosophical position intelligible to the general reader in our own
way.
The Baker-street Bazaar has just been exhibiting its familiar annual
spectacle. Straight-backed, small-headed, big-barrelled oxen, as
dissimilar from any wild species as can well be imagined, contended for
attention and praise with sheep of half-a-dozen different breeds and
styes of bloated preposterous pigs, no more like a wild boar or sow than
a city alderman is like an ourang-outang. The cattle show has been, and
perhaps may again be, succeeded by a poultry show, of whose crowing and
clucking prodigies it can only be certainly predicated that they will be
very unlike the aboriginal _Phasianus Gallus_. If the seeker after
animal anomalies is not satisfied, a turn or two in Seven Dials will
convince him that the breeds of pigeons are quite as extraordinary and
unlike one another and their parent stock, while the Horticultural
Society will provide him with any number of corresponding vegetable
aberrations from nature's types. He will learn with no little surprise,
too, in the course of his travels, that the proprietors and producers of
these animal and vegetable anomalies regard them as distinct species,
with a firm belief, the strength of which is exactly proportioned to
their ignorance of scientific biology, and which is the more remarkable
as they are all proud of their skill in _originating_ such "species."
On careful inquiry it is found that all these, and the many other
artificial breeds or races of animals and plants, have been produced by
one method. The breeder--and a skilful one must be a person of much
sagacity and natural or acquired perceptive faculty--notes some slight
difference, arising he knows not how, in some individuals of his stock.
If he wish to perpetuate the difference, to form a breed with the
peculiarity in question strongly marked, he selects such male and female
individuals as exhibit the desired character, and breeds from them.
Their offspring are then carefully examined, and those which exhibit the
peculiarity the most distinctly are selected for breeding, and this
operation is repeated until the desired amount of divergence from the
primitive stock is reached. It is then found that by continuing the
process of selection--always breeding, that is, from well-marked forms,
and allowing no impure crosses to interfere,--a race may be formed, the
tendency of which to reproduce itself is exceedingly strong; nor is the
limit to the amount of divergence which may be thus produced known, but
one thing is certain, that, if certain breeds of dogs, or of pigeons, or
of horses, were known only in a fossil state, no naturalist would
hesitate in regarding them as distinct species.
But, in all these cases we have _human interference_. Without the
breeder there would be no selection, and without the selection no race.
Before admitting the possibility of natural species having originated in
any similar way, it must be proved that there is in nature some power
which takes the place of man, and performs a selection _suâ sponte_. It
is the claim of Mr. Darwin that he professes to have discovered the
existence and the _modus operandi_ of this natural selection, as he
terms it; and, if he be right, the process is perfectly simple and
comprehensible, and irresistibly deducible from very familiar but well
nigh forgotten facts.
Who, for instance, has duly reflected upon all the consequences of the
marvellous struggle for existence which is daily and hourly going on
among living beings? Not only does every animal live at the expense of
some other animal or plant, but the very plants are at war. The ground
is full of seeds that cannot rise into seedlings; the seedlings rob one
another of air and light and water, the strongest robber winning the
day, and extinguishing his competitors. Year after year, the wild
animals with which man never interferes are, on the average, neither
more nor less numerous than they were; and yet we know that the annual
produce of every pair is from one to perhaps a million young,--so that
it is mathematically certain that, on the average, as many are killed by
natural causes as are born every year, and those only escape which
happen to be a little better fitted to resist destruction than those
which die. The individuals of a species are like the crew of a foundered
ship, and none but good swimmers have a chance of reaching the land.
Such being unquestionably the necessary conditions under which living
creatures exist, Mr. Darwin discovers in them the instrument of natural
selection. Suppose that in the midst of this incessant competition some
individuals of a species (A) present accidental variations which happen
to fit them a little better than their fellows for the struggle in which
they are engaged, then the chances are in favour, not only of these
individuals being better nourished than the others, but of their
predominating over their fellows in other ways, and of having a better
chance of leaving offspring, which will of course tend to reproduce the
peculiarities of their parents. Their offspring will, by a parity of
reasoning, tend to predominate over their contemporaries, and there
being (suppose) no room for more than one species such as A, the weaker
variety will eventually be destroyed by the new destructive influence
which is thrown into the scale, and the stronger will take its place.
Surrounding conditions remaining unchanged, the new variety (which we
may call B)--supposed, for argument's sake, to be the best adapted for
these conditions which can be got out of the original stock--will remain
unchanged, all accidental deviations from the type becoming at once
extinguished, as less fit for their post than B itself. The tendency of
B to persist will grow with its persistence through successive
generations, and it will acquire all the characters of a new species.
But, on the other hand, if the conditions of life change in any degree,
however slight, B may no longer be that form which is best adapted to
withstand their destructive, and profit by their sustaining, influence;
in which case if it should give rise to a more competent variety (C),
this will take its place and become a new species; and thus, by _natural
selection_, the species B and C will be successively derived from A.
That this most ingenious hypothesis enables us to give a reason for many
apparent anomalies in the distribution of living beings in time and
space, and that it is not contradicted by the main phenomena of life and
organization appear to us to be unquestionable, and so far it must be
admitted to have an immense advantage over any of its predecessors. But
it is quite another matter to affirm absolutely either the truth or
falsehood of Mr. Darwin's views at the present stage of the inquiry.
Goethe has an excellent aphorism defining that state of mind which he
calls _Thätige Skepsis_--active doubt. It is doubt which so loves truth
that it neither dares rest in doubting, nor extinguish itself by
unjustified belief; and we commend this state of mind to students of
species, with respect to Mr. Darwin's or any other hypothesis, as to
their origin. The combined investigations of another 20 years may,
perhaps, enable naturalists to say whether the modifying causes and the
selective power, which Mr. Darwin has satisfactorily shown to exist in
nature, are competent to produce all the effects he ascribes to them, or
whether, on the other hand, he has been led to over-estimate the value
of his principle of natural selection, as greatly as Lamarck
over-estimated his _vera causa_ of modification by exercise.
But there is, at all events, one advantage possessed by the more recent
writer over his predecessor. Mr. Darwin abhors mere speculation as
nature abhors a vacuum. He is as greedy of cases and precedents as any
constitutional lawyer, and all the principles he lays down are capable
of being brought to the test of observation and experiment. The path he
bids us follow professes to be not a mere airy track, fabricated of
ideal cobwebs, but a solid and broad bridge of facts. If it be so, it
will carry us safely over many a chasm in our knowledge, and lead us to
a region free from the snares of those fascinating but barren Virgins,
the Final Causes, against whom a high authority has so justly warned us.
"My sons, dig in the vineyard," were the last words of the old man in
the fable; and, though the sons found no treasure, they made their
fortunes by the grapes.
XV
A LOBSTER; OR, THE STUDY OF
ZOOLOGY
Natural History is the name familiarly applied to the study of the
properties of such natural bodies as minerals, plants, and animals; the
sciences which embody the knowledge man has acquired upon these subjects
are commonly termed Natural Sciences, in contradistinction to other,
so-called "physical," sciences; and those who devote themselves
especially to the pursuit of such sciences have been, and are, commonly
termed "Naturalists."
Linnæus was a naturalist in this wide sense, and his "Systema Naturæ"
was a work upon natural history in the broadest acceptation of the term;
in it, that great methodizing spirit embodied all that was known in his
time of the distinctive characters of minerals, animals, and plants. But
the enormous stimulus which Linnæus gave to the investigation of nature
soon rendered it impossible that any one man should write another
"Systema Naturæ," and extremely difficult for any one to become a
naturalist such as Linnæus was.
Great as have been the advances made by all the three branches of
science, of old included under the title of natural history, there can
be no doubt that zoology and botany have grown in an enormously greater
ratio than mineralogy, and hence, as I suppose, the name of "natural
history" has gradually become more and more definitely attached to these
prominent divisions of the subject, and by "naturalist" people have
meant more and more distinctly to imply a student of the structure and
functions of living beings.
However this may be, it is certain that the advance of knowledge has
gradually widened the distance between mineralogy and its old
associates, while it has drawn zoology and botany closer together; so
that of late years it has been found convenient (and indeed necessary)
to associate the sciences which deal with vitality and all its phenomena
under the common head of "biology"; and the biologists have come to
repudiate any blood-relationship with their foster-brothers, the
mineralogists.
Certain broad laws have a general application throughout both the animal
and the vegetable worlds, but the ground common to these kingdoms of
nature is not of very wide extent, and the multiplicity of details is so
great, that the student of living beings finds himself obliged to devote
his attention exclusively either to the one or the other. If he elects
to study plants, under any aspect, we know at once what to call him; he
is a botanist and his science is botany. But if the investigation of
animal life be his choice, the name generally applied to him will vary,
according to the kind of animals he studies, or the particular phenomena
of animal life to which he confines his attention. If the study of man
is his object, he is called an anatomist, or a physiologist, or an
ethnologist; but if he dissects animals, or examines into the mode in
which their functions are performed, he is a comparative anatomist or
comparative physiologist. If he turns his attention to fossil animals he
is a palæontologist. If his mind is more particularly directed to the
description, specific discrimination, classification, and distribution
of animals he is termed a zoologist.
For the purposes of the present discourse, however, I shall recognise
none of these titles save the last, which I shall employ as the
equivalent of botanist, and I shall use the term zoology as denoting the
whole doctrine of animal life, in contradistinction from botany, which
signifies the whole doctrine of vegetable life.
Employed in this sense, zoology, like botany, is divisible into three
great but subordinate sciences, morphology, physiology, and
distribution, each of which may, to a very great extent, be studied
independently of the other.
Zoological morphology is the doctrine of animal form or structure.
Anatomy is one of its branches, development is another; while
classification is the expression of the relations which different
animals bear to one another, in respect of their anatomy and their
development.
Zoological distribution is the study of animals in relation to the
terrestrial conditions which obtain now, or have obtained at any
previous epoch of the earth's history.
Zoological physiology, lastly, is the doctrine of the functions or
actions of animals. It regards animal bodies as machines impelled by
certain forces, and performing an amount of work, which can be expressed
in terms of the ordinary forces of nature. The final object of
physiology is to deduce the facts of morphology on the one hand, and
those of distribution on the other, from the laws of the molecular
forces of matter.
Such is the scope of zoology. But if I were to content myself with the
enunciation of these dry definitions, I should ill exemplify that method
of teaching this branch of physical science, which it is my chief
business to-night to recommend. Let us turn away then from abstract
definitions. Let us take some concrete living thing, some animal, the
commoner the better, and let us see how the application of common sense
and common logic to the obvious facts it presents, inevitably leads us
into all these branches of zoological science.
I have before me a lobster. When I examine it, what appears to be the
most striking character it presents? Why, I observe that this part which
we call the tail of the lobster, is made up of six distinct hard rings
and a seventh terminal piece. If I separate one of the middle rings, say
the third, I find it carries upon its under surface a pair of limbs or
appendages, each of which consists of a stalk and two terminal pieces.
So that I can represent a transverse section of the ring and its
appendages upon the diagram board in this way.
If I now take the fourth ring, I find it has the same structure, and so
have the fifth and the second; so that in each of these divisions of
the tail I find parts which correspond with one another, a ring and two
appendages; and in each appendage a stalk and two end pieces. These
corresponding parts are called in the technical language of anatomy
"homologous parts." The ring of the third division is the "homologue" of
the ring of the fifth, the appendage of the former is the homologue of
the appendage of the latter. And as each division exhibits corresponding
parts in corresponding places, we say that all the divisions are
constructed upon the same plan. But now let us consider the sixth
division. It is similar to, and yet different from, the others. The ring
is essentially the same as in the other divisions; but the appendages
look at first as if they were very different; and yet when we regard
them closely, what do we find? A stalk and two terminal divisions
exactly as in the others, but the stalk is very short and very thick,
the terminal divisions are very broad and flat, and one of them is
divided into two pieces.
I may say, therefore, that the sixth segment is like the others in plan,
but that it is modified in its details.
The first segment is like the others, so far as its ring is concerned,
and though its appendages differ from any of those yet examined in the
simplicity of their structure, parts corresponding with the stem and one
of the divisions of the appendages of the other segments can be readily
discerned in them.
Thus it appears that the lobster's tail is composed of a series of
segments which are fundamentally similar, though each presents peculiar
modifications of the plan common to all. But when I turn to the forepart
of the body I see, at first, nothing but a great shield-like shell,
called technically the "carapace," ending in front in a sharp spine, on
either side of which are the curious compound eyes, set upon the ends of
stout moveable stalks. Behind these, on the under side of the body, are
two pairs of long feelers or antennæ, followed by six pairs of jaws,
folded against one another over the mouth, and five pairs of legs, the
foremost of these being the great pinchers, or claws, of the lobster.
It looks, at first, a little hopeless to attempt to find in this
complex mass a series of rings, each with its pair of appendages, such
as I have shown you in the abdomen, and yet it is not difficult to
demonstrate their existence. Strip off the legs, and you will find that
each pair is attached to a very definite segment of the under wall of
the body; but these segments, instead of being the lower parts of free
rings, as in the tail, are such parts of rings which are all solidly
united and bound together; and the like is true of the jaws, the
feelers, and the eye-stalks, every pair of which is borne upon its own
special segment. Thus the conclusion is gradually forced upon us that
the body of the lobster is composed of as many rings as there are pairs
of appendages, namely, twenty in all, but that the six hindmost rings
remain free and moveable, while the fourteen front rings become firmly
soldered together, their backs forming one continuous shield--the
carapace.
Unity of plan, diversity in execution, is the lesson taught by the study
of the rings of the body, and the same instruction is given still more
emphatically by the appendages. If I examine the outermost jaw I find it
consists of three distinct portions, an inner, a middle, and an outer,
mounted upon a common stem; and if I compare this jaw with the legs
behind it, or the jaws in front of it, I find it quite easy to see,
that, in the legs, it is the part of the appendage which corresponds
with the inner division, which becomes modified into what we know
familiarly as the "leg," while the middle division disappears, and the
outer division is hidden under the carapace. Nor is it more difficult to
discern that, in the appendages of the tail, the middle division appears
again and the outer vanishes; while on the other hand, in the foremost
jaw, the so-called mandible, the inner division only is left; and, in
the same way, the parts of the feelers and of the eye-stalks, can be
identified with those of the legs and jaws.
But whither does all this tend? To the very remarkable conclusion that a
unity of plan, of the same kind as that discoverable in the tail or
abdomen of the lobster, pervades the whole organization of its skeleton,
so that I can return to the diagram representing any one of the rings
of the tail, which I drew upon the board, and by adding a third division
to each appendage, I can use it as a sort of scheme or plan of any ring
of the body. I can give names to all the parts of that figure, and then
if I take any segment of the body of the lobster, I can point out to you
exactly, what modification the general plan has undergone in that
particular segment; what part has remained moveable, and what has become
fixed to another; what has been excessively developed and metamorphosed,
and what has been suppressed.
But I imagine I hear the question, how is all this to be tested? No
doubt it is a pretty and ingenious way of looking at the structure of
any animal, but is it anything more? Does Nature acknowledge in any
deeper way this unity of plan we seem to trace?
The objection suggested by these questions is a very valid and important
one, and morphology was in an unsound state, so long as it rested upon
the mere perception of the analogies which obtain between fully formed
parts. The unchecked ingenuity of speculative anatomists proved itself
fully competent to spin any number of contradictory hypotheses out of
the same facts, and endless morphological dreams threatened to supplant
scientific theory.
Happily, however, there is a criterion of morphological truth, and a
sure test of all homologies. Our lobster has not always been what we see
it; it was once an egg, a semi-fluid mass of yolk, not so big as a pin's
head, contained in a transparent membrane, and exhibiting not the least
trace of any one of those organs, whose multiplicity and complexity, in
the adult, are so surprising. After a time a delicate patch of cellular
membrane appeared upon one face of this yolk, and that patch was the
foundation of the whole creature, the clay out of which it would be
moulded. Gradually investing the yolk, it became subdivided by
transverse constrictions into segments, the forerunners of the rings of
the body. Upon the ventral surface of each of the rings thus sketched
out, a pair of bud-like prominences made their appearance--the rudiments
of the appendages of the ring. At first, all the appendages were alike,
but, as they grew, most of them became distinguished with a stem and
two terminal divisions, to which in the middle part of the body was
added a third outer division; and it was only at a later period, that by
the modification, or abortion, of certain of these primitive
constituents, the limbs acquired their perfect form.
Thus the study of development proves that the doctrine of unity of plan
is not merely a fancy, that it is not merely one way of looking at the
matter, but that it is the expression of deep-seated natural facts. The
legs and jaws of the lobster may not merely be regarded as modifications
of a common type,--in fact and in nature they are so,--the leg and the
jaw of the young animal being, at first, indistinguishable.
These are wonderful truths, the more so because the zoologist finds them
to be of universal application. The investigation of a polype, of a
snail, of a fish, of a horse, or of a man would have led us, though by a
less easy path, perhaps, to exactly the same point. Unity of plan
everywhere lies hidden under the mask of diversity of structure--the
complex is everywhere evolved out of the simple. Every animal has at
first the form of an egg, and every animal and every organic part, in
reaching its adult state, passes through conditions common to other
animals and other adult parts; and this leads me to another point. I
have hitherto spoken as if the lobster were alone in the world, but, as
I need hardly remind you, there are myriads of other animal organisms.
Of these some, such as men, horses, birds, fishes, snails, slugs,
oysters, corals, and sponges, are not in the least like the lobster. But
other animals, though they may differ a good deal from the lobster, are
yet either very like it, or are like something that is like it. The cray
fish, the rock lobster, and the prawn, and the shrimp, for example,
however different, are yet so like lobsters, that a child would group
them as of the lobster kind, in contradistinction to snails and slugs;
and these last again would form a kind by themselves, in
contradistinction to cows, horses, and sheep, the cattle kind.
But this spontaneous grouping into "kinds" is the first essay of the
human mind at classification, or the calling by a common name of those
things that are alike, and the arranging them in such a manner as best
to suggest the sum of their likenesses and unlikenesses to other things.
Those kinds which include no other subdivisions than the sexes, or
various breeds, are called, in technical language, species. The English
lobster is a species, our cray fish is another, our prawn is another. In
other countries, however, there are lobsters, cray fish, and prawns,
very like ours, and yet presenting sufficient differences to deserve
distinction. Naturalists, therefore, express this resemblance and this
diversity by grouping them as distinct species of the same "genus." But
the lobster and the cray fish, though belonging to distinct genera, have
many features in common, and hence are grouped together in an assemblage
which is called a family. More distant resemblances connect the lobster
with the prawn and the crab, which are expressed by putting all these
into the same order. Again, more remote, but still very definite,
resemblances unite the lobster with the woodlouse, the king crab, the
water flea, and the barnacle, and separate them from all other animals;
whence they collectively constitute the larger group, or class,
_Crustacea_. But the _Crustacea_ exhibit many peculiar features in
common with insects, spiders, and centipedes, so that these are grouped
into the still larger assemblage or "province" _Articulata_, and,
finally, the relations which these have to worms and other lower
animals, are expressed by combining the whole vast aggregate into the
sub-kingdom _Annulosa_.
If I had worked my way from a sponge instead of a lobster, I should have
found it associated, by like ties, with a great number of other animals
into the sub-kingdom _Protozoa_; if I had selected a fresh-water polype
or a coral, the members of what naturalists term the sub-kingdom
_Coelenterata_, would have grouped themselves around my type; had a
snail been chosen, the inhabitants of all univalve and bivalve, land and
water shells, the lamp shells, the squids, and the sea-mat would have
gradually linked themselves on to it as members of the same sub-kingdom
of _Mollusca_; and finally starting from man, I should have been
compelled to admit first, the ape, the rat, the horse, the dog, into
the same class, and then the bird, the crocodile, the turtle, the frog,
and the fish, into the same sub-kingdom of _Vertebrata_.
And if I had followed out all these various lines of classification
fully, I should discover in the end that there was no animal, either
recent or fossil, which did not at once fall into one or other of these
sub-kingdoms. In other words, every animal is organised upon one or
other of the five, or more, plans, whose existence renders our
classification possible. And so definitely and precisely marked is the
structure of each animal that, in the present state of our knowledge,
there is not the least evidence to prove that a form, in the slightest
degree transitional between any two of the groups _Vertebrata_,
_Annulosa_, _Mollusca_, and _Coelenterata_, either exists, or has
existed, during that period of the earth's history which is recorded by
the geologist. Nevertheless, you must not for a moment suppose, because
no such transitional forms are known, that the members of the
sub-kingdoms are disconnected from, or independent of, one another. On
the contrary, in their earliest condition they are all alike, and the
primordial germs of a man, a dog, a bird, a fish, a beetle, a snail, and
a polype are in no essential structural respects, distinguishable.
In this broad sense, it may with truth be said, that all living animals,
and all those dead creations which geology reveals, are bound together
by an all-pervading unity of organisation, of the same character, though
not equal in degree, to that which enables us to discern one and the
same plan amidst the twenty different segments of a lobster's body.
Truly it has been said, that to a clear eye the smallest fact is a
window through which the Infinite may be seen.
Turning from these purely morphological considerations, let us now
examine into the manner in which the attentive study of the lobster
impels us into other lines of research.
Lobsters are found in all the European seas; but on the opposite shores
of the Atlantic and in the seas of the southern hemisphere they do not
exist. They are, however, represented in these regions by very closely
allied, but distinct forms--the _Homarus Americanus_ and the _Homarus
Capensis_, so that we may say that the European has one species of
_Homarus_; the American, another; the African, another; and thus the
remarkable facts of geographical distribution begin to dawn upon us.
Again, if we examine the contents of the earth's crust, we shall find in
the later of those deposits, which have served as the great burying
grounds of past ages, numberless lobster-like animals, but none so
similar to our living lobster as to make zoologists sure that they
belonged even to the same genus. If we go still further back in time, we
discover in the oldest rocks of all, the remains of animals, constructed
on the same general plan as the lobster, and belonging to the same great
group of _Crustacea_; but for the most part totally different from the
lobster, and indeed from any other living form of crustacean; and thus
we gain a notion of that successive change of the animal population of
the globe, in past ages, which is the most striking fact revealed by
geology.
Consider, now, where our inquiries have led us. We studied our type
morphologically, when we determined its anatomy and its development, and
when comparing it, in these respects, with other animals, we made out
its place in a system of classification. If we were to examine every
animal in a similar manner we should establish a complete body of
zoological morphology.
Again, we investigated the distribution of our type in space and in
time, and, if the like had been done with every animal, the sciences of
geographical and geological distribution would have attained their
limit.
But you will observe one remarkable circumstance, that, up to this
point, the question of the life of these organisms has not come under
consideration. Morphology and distribution might be studied almost as
well, if animals and plants were a peculiar kind of crystals and
possessed none of those functions which distinguish living beings so
remarkably. But the facts of morphology and distribution have to be
accounted for, and the science, whose aim it is to account for them, is
physiology.
Let us return to our lobster once more. If we watched the creature in
its native element, we should see it climbing actively the submerged
rocks, among which it delights to live, by means of its strong legs; or
swimming by powerful strokes of its great tail, the appendages of whose
sixth joint are spread out into a broad fan-like propeller; seize it and
it will show you that its great claws are no mean weapons of offence;
suspend a piece of carrion among its haunts, and it will greedily devour
it, tearing and crushing the flesh by means of its multitudinous jaws.
Suppose that we had known nothing of the lobster but as an inert mass,
an organic crystal, if I may use the phrase, and that we could suddenly
see it exerting all these powers, what wonderful new ideas and new
questions would arise in our minds! The great new question would be "How
does all this take place?" the chief new idea would be the idea of
adaptation to purpose,--the notion that the constituents of animal
bodies are not mere unconnected parts, but organs working together to an
end. Let us consider the tail of the lobster again from this point of
view. Morphology has taught us that it is a series of segments composed
of homologous parts, which undergo various modifications--beneath and
through which a common plan of formation is discernible. But if I look
at the same part physiologically, I see that it is a most beautifully
constructed organ of locomotion, by means of which the animal can
swiftly propel itself either backwards or forwards.
But how is this remarkable propulsive machine made to perform its
functions? If I were suddenly to kill one of these animals and to take
out all the soft parts, I should find the shell to be perfectly inert,
to have no more power of moving itself than is possessed by the
machinery of a mill, when disconnected from its steam-engine or
water-wheel. But if I were to open it, and take out the viscera only,
leaving the white flesh, I should perceive that the lobster could bend
and extend its tail as well as before. If I were to cut off the tail I
should cease to find any spontaneous motion in it--but on pinching any
portion of the flesh, I should observe that it underwent a very curious
change--each fibre becoming shorter and thicker. By this act of
contraction, as it is termed, the parts to which the ends of the fibre
are attached are, of course, approximated--and according to the
relations of their points of attachment to the centres of motions of the
different rings, the bending or the extension of the tail results. Close
observation of the newly-opened lobster would soon show that all its
movements are due to the same cause--the shortening and thickening of
these fleshy fibres, which are technically called muscles.
Here, then, is a capital fact. The movements of the lobster are due to
muscular contractility. But why does a muscle contract at one time and
not at another? Why does one whole group of muscles contract when the
lobster wishes to extend his tail, and another group, when he desires to
bend it? What is it originates, directs and controls, the motive power?
Experiment, the great instrument for the ascertainment of truth in
physical science, answers this question for us. In the head of the
lobster there lies a small mass of that peculiar tissue which is known
as nervous substance. Cords of similar matter connect this brain of the
lobster, directly or indirectly, with the muscles. Now, if these
communicating cords are cut, the brain remaining entire, the power of
exerting what we call voluntary motion in the parts below the section is
destroyed, and on the other hand, if, the cords remaining entire, the
brain mass be destroyed, the same voluntary mobility is equally lost.
Whence the inevitable conclusion is, that the power of originating these
motions resides in the brain, and is propagated along the nervous cords.
In the higher animals the phenomena which attend this transmission have
been investigated, and the exertion of the peculiar energy which resides
in the nerves, has been found to be accompanied by a disturbance of the
electrical state of their molecules.
If we could exactly estimate the signification of this disturbance; if
we could obtain the value of a given exertion of nerve force by
determining the quantity of electricity or of heat of which it is the
equivalent; if we could ascertain upon what arrangement, or other
condition of the molecules of matter, the manifestation of the nervous
and muscular energies depends, (and doubtless science will some day or
other ascertain these points,) physiologists would have attained their
ultimate goal in this direction; they would have determined the relation
of the motive force of animals to the other forms of force found in
nature; and if the same process had been successfully performed for all
the operations which are carried on, in and by, the animal frame,
physiology would be perfect, and the facts of morphology and
distribution would be deducible from the laws which physiologists had
established, combined with those determining the condition of the
surrounding universe.
There is not a fragment of the organism of this humble animal, whose
study would not lead us into regions of thought as large as those which
I have briefly opened up to you; but what I have been saying, I trust,
has not only enabled you to form a conception of the scope and purport
of zoology, but has given you an imperfect example of the manner in
which, in my opinion, that science, or indeed any physical science, may
be best taught. The great matter is to make teaching real and practical,
by fixing the attention of the student on particular facts, but at the
same time it should be rendered broad and comprehensive by constant
reference to the generalizations of which all particular facts are
illustrations. The lobster has served as a type of the whole animal
kingdom, and its anatomy and physiology have illustrated for us some of
the greatest truths of biology. The student who has once seen for
himself the facts which I have described, has had their relations
explained to him, and has clearly comprehended them, has so far a
knowledge of zoology, which is real and genuine, however limited it may
be, and which is worth more than all the mere reading knowledge of the
science he could ever acquire. His zoological information is, so far,
knowledge and not mere hearsay.
And if it were my business to fit you for the certificate in zoological
science granted by this department, I should pursue a course precisely
similar in principle to that which I have taken to-night. I should
select a fresh-water sponge, a fresh-water polype or a _Cyanæa_, a
fresh-water mussel, a lobster, a fowl, as types of the five primary
divisions of the animal kingdom. I should explain their structure very
fully, and show how each illustrated the great principles of zoology.
Having gone very carefully and fully over this ground, I should feel
that you had a safe foundation, and I should then take you in the same
way, but less minutely, over similarly selected illustrative types of
the classes; and then I should direct your attention to the special
forms enumerated under the head of types, in this syllabus, and to the
other facts there mentioned.
That would, speaking generally, be my plan. But I have undertaken to
explain to you the best mode of acquiring and communicating a knowledge
of zoology, and you may therefore fairly ask me for a more detailed and
precise account of the manner in which I should propose to furnish you
with the information I refer to.
My own impression is that the best model for all kinds of training in
physical science is that afforded by the method of teaching anatomy, in
use in the medical schools. This method consists of three
elements--lectures, demonstrations, and examinations.
The object of lectures is, in the first place, to awaken the attention
and excite the enthusiasm of the student; and this, I am sure, may be
effected to a far greater extent by the oral discourse and by the
personal influence of a respected teacher, than in any other way.
Secondly, lectures have the double use of guiding the student to the
salient points of a subject, and at the same time forcing him to attend
to the whole of it, and not merely to that part which takes his fancy.
And lastly, lectures afford the student the opportunity of seeking
explanations of those difficulties which will, and indeed ought to,
arise in the course of his studies.
But for a student to derive the utmost possible value from lectures,
several precautions are needful.
I have a strong impression that the better the discourse is, as an
oration, the worse it is as a lecture. The flow of the discourse carries
you on without proper attention to its sense; you drop a word or a
phrase, you lose the exact meaning for a moment, and while you strive to
recover yourself, the speaker had passed on to something else.
The practice I have adopted in late years in lecturing to students, is
to condense the substance of the hour's discourse into a few dry
propositions, which are read slowly and taken down from dictation; the
reading of each being followed by a free commentary, expanding and
illustrating the proposition, explaining terms, and removing any
difficulties that may be attackable in that way, by diagrams made
roughly, and seen to grow under the lecturer's hand. In this manner you,
at any rate, insure the co-operation of the student to a certain extent.
He cannot leave the lecture-room entirely empty if the taking of notes
is enforced, and a student must be preternaturally dull and mechanical
if he can take notes and hear them properly explained, and yet learn
nothing.
What books shall I read? is a question constantly put by the student to
the teacher. My reply usually is, "None; write your notes out carefully
and fully; strive to understand them thoroughly; come to me for the
explanation of anything you cannot understand, and I would rather you
did not distract your mind by reading." A properly composed course of
lectures ought to contain fully as much matter as a student can
assimilate in the time occupied by its delivery; and the teacher should
always recollect that his business is to feed, and not to cram, the
intellect. Indeed, I believe that a student who gains from a course of
lectures the simple habit of concentrating his attention upon a
definitely limited series of facts, until they are thoroughly mastered,
has made a step of immeasurable importance.
But however good lectures may be, and however extensive the course of
reading by which they are followed up, they are but accessories to the
great instrument of scientific teaching--demonstration. If I insist
unweariedly, nay fanatically, upon the importance of physical science as
an educational agent, it is because the study of any branch of science,
if properly conducted, appears to me to fill up a void left by all other
means of education. I have the greatest respect and love for literature;
nothing would grieve me more than to see literary training other than a
very prominent branch of education; indeed, I wish that real literary
discipline were far more attended to than it is; but I cannot shut my
eyes to the fact that there is a vast difference between men who have
had a purely literary, and those who have had a sound scientific,
training.
Seeking for the cause of this difference, I imagine I can find it in the
fact, that, in the world of letters, learning and knowledge are one, and
books are the source of both; whereas in science, as in life, learning
and knowledge are distinct, and the study of things, and not of books,
is the source of the latter.
All that literature has to bestow may be obtained by reading and by
practical exercise in writing and in speaking; but I do not exaggerate
when I say, that none of the best gifts of science are to be won by
these means. On the contrary, the great benefit which a scientific
education bestows, whether as training or as knowledge, is dependent
upon the extent to which the mind of the student is brought into
immediate contact with facts--upon the degree to which he learns the
habit of appealing directly to nature, and of acquiring through his
senses concrete images of those properties of things, which are and
always will be, but approximately expressed in human language. Our way
of looking at nature, and of speaking about her, varies from year to
year; but a fact once seen, a relation of cause and effect, once
demonstratively apprehended, are possessions which neither change nor
pass away, but, on the contrary, form fixed centres, about which other
truths aggregate by natural affinity.
Therefore, the great business of the scientific teacher is, to imprint
the fundamental, irrefragable, facts of his science, not only by words
upon the mind, but by sensible impressions upon the eye and ear and
touch, of the student, in so complete a manner that every term used, or
law enunciated, should afterwards call up vivid images of the particular
structural, or other, facts which furnished the demonstration of the
law, or the illustration of the term.
Now this important operation can only be achieved by constant
demonstration, which may take place to a certain imperfect extent during
a lecture, but which ought also to be carried on independently, and
which should be addressed to each individual student, the teacher
endeavouring, not so much to show a thing to the learner, as to make him
see it for himself.
I am well aware that there are great practical difficulties in the way
of effectual zoological demonstrations. The dissection of animals is not
altogether pleasant, and requires much time; nor is it easy to secure an
adequate supply of the needful specimens. The botanist has here a great
advantage; his specimens are easily obtained, are clean and wholesome,
and can be dissected in a private house as well as anywhere else; and
hence, I believe, the fact, that botany is so much more readily and
better taught than its sister science. But, be it difficult or be it
easy, if zoological science is to be properly studied, demonstration,
and, consequently, dissection, must be had. Without it, no man can have
a really sound knowledge of animal organization.
A good deal may be done, however, without actual dissection on the
student's part, by demonstrating upon specimens and preparations, and in
all probability it would not be very difficult, were the demand
sufficient, to organise collections of such objects, sufficient for all
the purposes of elementary teaching, at a comparatively cheap rate. Even
without these, much might be effected, if the zoological collections,
which are open to the public, were arranged according to what has been
termed the "typical principle"; that is to say, if the specimens exposed
to public view were so selected, that the public could learn something
from them, instead of being, as at present, merely confused by their
multiplicity. For example, the grand ornithological gallery at the
British Museum contains between two and three thousand species of birds,
and sometimes five or six specimens of a species. They are very pretty
to look at and some of the cases are, indeed, splendid; but I will
undertake to say, that no man but a professed ornithologist has ever
gathered much information from the collection. Certainly, no one of the
tens of thousands of the general public who have walked through that
gallery ever knew more about the essential peculiarities of birds when
he left the gallery, than when he entered it. But if, somewhere in that
vast hall, there were a few preparations, exemplifying the leading
structural peculiarities and the mode of development of a common fowl;
if the types of the genera, the leading modifications in the skeleton,
in the plumage at various ages, in the mode of nidification, and the
like, among birds, were displayed; and if the other specimens were put
away in a place where the men of science, to whom they are alone useful,
could have free access to them, I can conceive that this collection
might become a great instrument of scientific education.[66]
The last implement of the teacher to which I have adverted is
examination--a means of education now so thoroughly understood that I
need hardly enlarge upon it. I hold that both written and oral
examinations are indispensable, and, by requiring the description of
specimens, they may be made to supplement demonstration.
* * * * *
Such is the fullest reply the time at my disposal will allow me to give
to the question--how may a knowledge of zoology be best acquired and
communicated?
But there is a previous question which may be moved, and which, in fact,
I know many are inclined to move. It is the question why should training
masters be encouraged to acquire a knowledge of this, or any other
branch, of physical science? What is the use, it is said, of attempting
to make physical science a branch of primary education? Is it not
probable that teachers, in pursuing such studies, will be led astray
from the acquirement of more important but less attractive knowledge?
And, even if they can learn something of science without prejudice to
their usefulness, what is the good of their attempting to instil that
knowledge into boys whose real business is the acquisition of reading,
writing, and arithmetic?
These questions are, and will be, very commonly asked, for they arise
from that profound ignorance of the value and true position of physical
science, which infests the minds of the most highly educated and
intelligent classes of the community. But if I did not feel well
assured that they are capable of being easily and satisfactorily
answered; that they have been answered over and over again; and that the
time will come when men of liberal education will blush to raise such
questions,--I should be ashamed of my position here to-night. Without
doubt, it is your great and very important function to carry out
elementary education; without question, anything that should interfere
with the faithful fulfilment of that duty on your part would be a great
evil; and if I thought that your acquirement of the elements of physical
science and your communication of those elements to your pupils,
involved, any sort of interference with your proper duties, I should be
the first person to protest against your being encouraged to do anything
of the kind.
But is it true that the acquisition of such a knowledge of science as is
proposed, and the communication of that knowledge, are calculated to
weaken your usefulness? or may I not rather ask is it possible for you
to discharge your functions properly, without these aids?
What is the purpose of primary intellectual education? I apprehend that
its first object is to train the young in the use of those tools
wherewith men extract knowledge from the ever-shifting succession of
phenomena which pass before their eyes; and that its second object is to
inform them of the fundamental laws which have been found by experience
to govern the course of things, so that they may not be turned out into
the world naked, defenceless, and a prey to the events they might
control.
A boy is taught to read his own and other languages, in order that he
may have access to infinitely wider stores of knowledge than could ever
be opened to him by oral intercourse with his fellow men; he learns to
write, that his means of communication with the rest of mankind may be
indefinitely enlarged, and that he may record and store up the knowledge
he acquires. He is taught elementary mathematics that he may understand
all those relations of number and form, upon which the transactions of
men, associated in complicated societies, are built, and that he may
have some practice in deductive reasoning.
All these operations of reading, writing, and ciphering, are
intellectual tools whose use should, before all things, be learned, and
learned thoroughly; so that the youth may be enabled to make his life
that which it ought to be, a continual progress in learning and in
wisdom.
But, in addition, primary education endeavours to fit a boy out with a
certain equipment of positive knowledge. He is taught the great laws of
morality; the religion of his sect; so much history and geography as
will tell him where the great countries of the world are, what they are,
and how they have become what they are.
Without doubt all these are most fitting and excellent things to teach a
boy; I should be very sorry to omit any of them from any scheme of
primary intellectual education. The system is excellent so far as it
goes.
But if I regard it closely a curious reflection arises. I suppose that
fifteen hundred years ago, the child of any well-to-do Roman citizen was
taught just these same things; reading and writing in his own and,
perhaps, the Greek tongue; the elements of mathematics; and the
religion, morality, history, and geography current in his time.
Furthermore, I do not think I err in affirming, that, if such a
Christian Roman boy, who had finished his education, could be
transplanted into one of our public schools, and pass through its course
of instruction, he would not meet with a single unfamiliar line of
thought; amidst all the new facts he would have to learn, not one would
suggest a different mode of regarding the universe from that current in
his own time.
And yet surely there is some great difference between the civilization
of the fourth century and that of the nineteenth, and still more between
the intellectual habits and tone of thought of that day and of this?
And what has made this difference? I answer fearlessly: The prodigious
development of physical science within the last two centuries.
Modern civilisation rests upon physical science; take away her gifts to
our own country, and our position among the leading nations of the world
is gone to-morrow; for it is physical science only, that makes
intelligence and moral energy stronger than brute force.
The whole of modern thought is steeped in science; it has made its way
into the works of our best poets, and even the mere man of letters, who
affects to ignore and despise science, is unconsciously impregnated with
her spirit and indebted for his best products to her methods. I believe
that the greatest intellectual revolution mankind has yet seen is now
slowly taking place by her agency. She is teaching the world that the
ultimate court of appeal is observation and experiment, and not
authority; she is teaching it to estimate the value of evidence; she is
creating a firm and living faith in the existence of immutable moral and
physical laws, perfect obedience to which is the highest possible aim of
an intelligent being.
But of all this your old stereotyped system of education takes no note.
Physical science, its methods, its problems and its difficulties will
meet the poorest boy at every turn, and yet we educate him in such a
manner that he shall enter the world, as ignorant of the existence of
the methods and facts of science, as the day he was born. The modern
world is full of artillery; and we turn out our children to do battle in
it, equipped with the shield and sword of an ancient gladiator.
Posterity will cry shame on us if we do not remedy this deplorable state
of things. Nay, if we live twenty years longer, our own consciences will
cry shame on us.
It is my firm conviction that the only way to remedy it is to make the
elements of physical science an integral part of primary education. I
have endeavoured to show you how that may be done for that branch of
science which it is my business to pursue; and I can but add, that I
should look upon the day when every schoolmaster throughout this land
was a centre of genuine, however rudimentary, scientific knowledge, as
an epoch in the history of the country.
But let me entreat you to remember my last words. Mere book learning in
physical science, is a sham and a delusion--what you teach, unless you
wish to be impostors, that you must first know; and real knowledge in
science, means personal acquaintance with the facts, be they few or
many.
FOOTNOTES:
[66] Since these remarks were made the Natural History Collection of the
British Museum has been removed to South Kensington, and Huxley himself
wrote later on: "The visitor to the Natural History Museum in 1894 need
go no further than the Great Hall to see the realisation of my hopes by
the present Director."
Printed by BALLANTYNE, HANSON & CO.
Edinburgh & London
* * * * *
TRANSCRIBER NOTES:
Punctuation has been normalized without note.
Inconsistent and archaic spelling in the original document
have been preserved. Obvious typographical errors have
been corrected.
Page 3: "adioning" changed to "adjoining" (and in the adjoining
regions).
Page 52, Footnote 3: "dergees" changed to "degrees" (Cape Negro is
in 16 degrees).
Page 67: "11/18" changed to "11/18ths" (not more than 11/18ths of
its length).
Page 151, Footnote 41: "pp." changed to "p." (From Müller's Archiv.,
1858, p. 453.)
Page 166: "kindgom" changed to "kingdom" (of the animal kingdom
which has been guessed at) and (with that of the animal kingdom).
Page 184: "order" changed to "orders" (Summing up all the orders of
animals).
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