The Project Gutenberg eBook of What you should know about your sensations
This eBook is for the use of anyone anywhere in the United States and
most other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms
of the Project Gutenberg License included with this eBook or online
at www.gutenberg.org. If you are not located in the United States,
you will have to check the laws of the country where you are located
before using this eBook.
Title: What you should know about your sensations
Author: Grace Kinckle Adams
Editor: E. Haldeman-Julius
Release date: June 30, 2026 [eBook #78983]
Language: English
Original publication: Girard: Haldeman-Julius Publications, 1929
Other information and formats: www.gutenberg.org/ebooks/78983
Credits: Tim Miller, Sam Lamb and the Online Distributed Proofreading Team at https://www.pgdp.net
*** START OF THE PROJECT GUTENBERG EBOOK WHAT YOU SHOULD KNOW ABOUT YOUR SENSATIONS ***
LITTLE BLUE BOOK NO. 1476
Edited by E. Haldeman-Julius
What You Should Know
About Your Sensations
Grace Adams
HALDEMAN-JULIUS PUBLICATIONS
GIRARD, KANSAS
Copyright, 1929,
Haldeman-Julius Company
PRINTED IN THE UNITED STATES OF AMERICA
CONTENTS
Page
The Importance of Sensations 5
The Nature of Sensations 7
How Sensations Occur 8
How We Feel 10
Visual Sensations 13
Common Abnormalities of Vision 16
How We See in the Light and in the Dark 19
The Importance of the Sense of Smell 22
The True Sense of Taste 24
The Complexity of Our Perceptions 26
Localization on the Skin 28
WHAT YOU SHOULD KNOW ABOUT YOUR SENSATIONS
THE IMPORTANCE OF SENSATIONS
Since man first became interested in the processes taking place in his
own mind, his dreams and emotions and thoughts, he has wondered if
he could understand these relatively elusive processes as thoroughly
as he could the more stable facts of the material universe. And ever
since Epictetus and Aristotle began to collect the facts of mental life
and formulate them into the laws which were later to become the basis
of the study of psychology, philosophers and theologians and natural
scientists have debated whether or not this study of the human mind
constituted a real science. The champions of both sides of the question
are worthy of attention.
Epictetus and Aristotle considered their psychological investigations
strictly scientific. Yet as fascinating and as authoritative as their
studies appeared to their contemporaries, their opinions lose value
today, because none of the discipline with which they were familiar are
accounted scientific by exact modern standards.
From the scientific movement to which Descartes gave such impetus in
the seventeenth century until the time of Herbert Spencer, psychology
was not considered a science but a mystical preoccupation not unlike
theology. In Diderot’s Encyclopedia of 1752 we find psychology defined
as that branch of philosophy which “defines the human soul and gives
an account of its activities.” Bacon also classified psychology as one
of the philosophies of the soul. With it he included soothsaying and
witchcraft which in his day were supposed to be the two most practical
applications of psychology.
Comte was the first authority to place psychology among the natural
sciences instead of the philosophies. But curiously enough the one
branch of psychology which he considered exact enough to be classified
along with biology was the one branch of psychology which today is
thought to be completely and absolutely unscientific--phrenology.
Since the time of Spencer, who accepted psychology as an independent
science following biology and preparatory to sociology, its scientific
status has been fairly generally accepted. Still there have been some
violent dissenters. Kant, in particular, prophesied that there could
never be a science of psychology because mental phenomena could never
be treated mathematically. And the old debate is still raging. John B.
Watson when he adopted his behavioristic platform threw aside all of
the laboriously got results of the introspectionists and functionalists
because he considered them inexact, and irremediably so, when compared
with the results of the biologists and chemists. Many of these same
introspectionists and functionalists feel that the revolutionary and
far-reaching theories of Freud and Jung and Adler are too hypothetical
and too general ever to form the basis of an exact science.
Yet in one field all but the most radically behavioristic admit that
traditional psychology has justified its scientific claims. This field
comprises the human sensations.
THE NATURE OF SENSATIONS
Sensations are the mental ultimates of the psychological universe just
as the chemical elements are the ultimates of the chemical universe.
Sensations are the colors that we see--the reds and greens and purples
and blacks and whites and greys; the tactual experiences that we
feel--the warmths and colds and tickles and pains and aches; the tones
and noises that we hear; all the vast number of odors that we smell
and our few simple tastes of salt, sweet, sour and bitter. Of course
these simple experiences very seldom appear isolated. They come to
us as integral parts of much more complex experiences, as the taste
of lemonade, the smell of a flower or the colors of a landscape. In
this they parallel the elements of the other sciences which must be
separated out, artificially if necessary, before they can be adequately
studied.
It is a little ironical that at the very time Kant was denying
that any mental phenomena could ever be treated mathematically the
psychologists, themselves, were bringing the facts of sensation
under mathematical laws and the natural scientists were accepting
these laws as scientific, for it is to be assumed that biologists
and physicists might be more jealous of the limits of an exact
science than philosophers. The natural scientists, however, did
more than complacently accept the psychologists’ own investigations
of sensations; they verified and extended them and pointed out new
fields for the psychologists to explore. This was, of course, no mere
altruistic gesture. Natural scientists, themselves, have a real and
pertinent interest in all sensory problems and it is in their solution
that we come to understand the relations between the three sciences of
physics, biology and psychology, the differences among them and their
interdependence on one another.
HOW SENSATIONS OCCUR
One particular physiological organ or group of organs is responsible
for each of our five senses: the internal ear for sound, the retina of
the eye for color, the papillae of the tongue for taste, and so on.
Each of these special organs responds to a definite type of physical
stimulation: the retina to vibrations of the ether, the internal
ear to sound waves, the tongue to chemical solutions. Every simple
psychological sensation has, then, a rather complicated causal history
and it depends not only on the form of the physical stimulus but also
on the peculiar make-up of its special organ.
Every physiological organ of the human body is, of course, subject to
a wide range of individual differences. Some hearts are weaker than
others, some livers more sluggish, and some lungs less efficient in
their functions. It is only natural that the sense organs should differ
also. And they do. Yet on the whole they are surprisingly uniform. All
eyes react so typically to certain physical stimuli, and all noses to
others, that physicists themselves call these stimuli by the names
of the psychological sensations that they normally evoke. A light
wave of 687 millimicrons, for example, is known as a red wave because
when it impinges upon the normal retina it produces a red sensation,
and a vibration of 527 is called a green wave for the same reason. A
temperature of 12 degrees centigrade is marked as cold because when it
stimulates the human skin it produces a cold sensation, and 45 degrees
C. is hot because it produces the psychological experience of heat.
Chemists are so familiar with the typical odors of certain substances
that they accept these odors as invariable attributes of the substance.
At times, however, our usually well behaved sense organs respond to
the wrong type of stimuli and paradoxical sensations result. Neither
ether vibrations nor sound waves are necessarily involved when we
receive a severe blow on the head, yet such an accident can cause our
ears to “ring” and our eyes to “see stars.” And a perfectly normal
human being can feel a cold indistinguishable from normal cold when his
skin is stimulated by a temperature of 45 degrees C. (or 113° F.). To
understand this paradox it is necessary to familiarize ourselves with
the anatomy and physiology of the skin.
HOW WE FEEL
The whole surface of the human skin is not equally sensitive to
stimulation. In fact, a very large proportion of it is completely
insensitive. But dotted throughout this insensitive area are hundreds
of thousands of tiny sense organs. They are clustered together much
thicker in some regions of the body than in others, and wherever
they are more numerous the skin is, of course, more sensitive; yet
everywhere there is a sufficient number of them to make us unaware,
unless we investigate carefully, that there are any portions which are
insensate. These organs are of three different kinds and each kind
is responsible for a special type of sensation. The most numerous,
the corpuscles of Meissner, give us our experiences of pressure, the
bulbs of Kraus provide our sensations of cold and the corpuscles of
Ruffini those of warmth. In a square centimeter of the skin there are
approximately twenty pressure spots, thirteen cold spots and two warm
spots.
When a pressure spot is touched very lightly by a small narrow object
it reacts with a sensation which may be described as a tickle. The same
sensation can be got by gently moving a hair on the forearm or the
back of the hand for the corpuscles of Meissner are situated directly
beneath and to the windward of the hair bulbs and a movement of the
hairs stimulates them adequately. If the pressure is made a little
stronger, the tickle becomes a sensation of contact. Both the tickle
and the contact are definitely experiences of pressure. If the same
pressure spot is stimulated very carefully by either a cold or a warm
object, the experience will still be one of pressure. The pressure will
be neither warm nor cold for the pressure spots can respond only with
tactual sensations. They are as insensitive to thermal stimulations as
are the many other portions of the skin where there are no temperature
spots. The warm and cold spots, alone, give us all our experience of
temperature.
When a cold spot is stimulated by an object whose temperature is
between 12 and 15 degrees C., a cold sensation is felt. When a stimulus
whose temperature is between 37 and 40 degrees C. is brought in contact
with a warm spot, the typical sensation of warmth results. If, however,
the cold stimulus is applied to the warm spot, nothing at all is felt.
The warm spots do not respond at all until the temperature reaches 37
degrees. Similarly the cold spots do not react to warm stimuli, warmth
can be realized only from a warm spot. Yet when the temperature reaches
45 degrees C. (113° F.) the cold spots do respond, but with neither
warmth nor heat. They are cold spots, not warm spots, therefore they
can react in only one way--with a cold sensation. So we find that
due to the physiological functioning of an anatomical sense organ, a
physically hot stimulus really feels cold.
These three groups of sense organs, the pressure, cold and warm spots,
are the only sense organs on the whole surface of the body. Even
the pain which we feel when our skin is pricked or lacerated is not
represented by a special organ. Pain is experienced whenever a nerve
is stimulated directly and cutting the skin immediately exposes a
nerve and pain results. The only other organs from which we receive
any tactual sensations are the muscle spindles which produce aches and
soreness, the spindles of the tendons from which come our sensations
of strain, and the corpuscles of the joints which give us subcutaneous
pressure. Yet think of the wealth of tactual experiences which we have
every day, in fact, every few minutes. Not only such gross experiences
as hunger and thirst and fatigue and dizziness, but simple perceptions
of wetness and oiliness and smoothness and roughness and heaviness
and lightness. There are no specific sense organs for any of these
experiences. They are brought about by the six sense organs already
mentioned and the free nerve endings of pain functioning singly or in
combination, in greater or less degree.
There are not even any special sense organs of heat. Yet heat appears
as a unique sensation. It is different from warmth because warmth is
essentially comfortable while heat has a distinct and disagreeable
sting. The characteristic sting of heat is recognized whenever we
refer to pepper and other spices as hot. Psychologically, of course,
the sensation of heat is unique and simple, but on its biological
side it is slightly complicated. It is occasioned by the simultaneous
response of a warm spot and a cold spot, or several warm and cold
spots, to a stimulus of more than 45 degrees C. And it can be produced
in no other way. The warm spots, of course respond normally, the cold
spots paradoxically. The normal response is more vigorous than the
paradoxical, consequently we do not often realize the sensory quality
of the cold, while the warmth comes into consciousness. Ordinarily,
then, heat is warm. With particular stimuli and in certain regions of
the body where cold spots are particularly numerous, however, trained
psychologists are able to detect a heat which is cold. Also it is not
an especially rare occurrence to feel cold when we plunge our hands
unknowingly into very hot water.
Wetness, which seems almost as simple as heat, is produced by the
simultaneous stimulation of a cold spot and a pressure spot. It is
really nothing more than a cold pressure. It is true that we speak of
being wet when we are in a warm bath, but it is only when the water
begins to cool that we get the typical wet perception. This explains
why cold objects so often feel damp when there is actually no moisture
on them and why it is very difficult to determine whether cloth is
dry or not when it is held close to a hot fire, also why we are so
generally unconscious of the continual moisture of our own bodies.
VISUAL SENSATIONS
The number of perceptions produced by the relatively few sense
organs of the skin seems quite insignificant when compared to the
many different colors occasioned by the activity of the retina of
the eye, for the microscopic organs in the retina bring about all
of our sensations of color and of light and shade. All of the rest
of the rather elaborate apparatus of the eye has to do with spacial
perceptions; with form and distance and movement and size.
The normal human retina is sensitive to only some four hundred wave
lengths of light. The others, like the ultra violet rays, lie outside
the visible spectrum. Yet so efficient is that one small layer of
the eye that it can convert these four hundred ether vibrations into
approximately twelve million hues and tints and chromas. This number
seems astounding because it would probably be impossible for anyone to
name as many as twelve hundred separate colors. In fact, although the
persons responsible for the new shades in women’s stockings seem to
have an unlimited color-vocabulary, most of us get along satisfactorily
with an extremely limited one. Yet the fact that only a very few of
these twelve million hues and shades have common names does not mean
that they cannot all be detected under suitable conditions. Take the
one color, black, for instance. How many vastly different shades do you
group under that one word?
You can probably name immediately some ten, or maybe twenty objects
which you would without hesitation describe as black. Black velvet,
black satin, black cotton, black wood, coal, soot, ink, and so on. It
is possible that it may never have occurred to you that these blacks
are not identical. Yet a little critical attention to them will show
you how very different they really are. The black paper looks decidedly
grayish when placed beside the velvet. The velvet, itself, begins to
pale when it is compared to the darkness of the inside of a black tube.
The same variety holds for whiteness. White paper is different from
white enamel and white paint. Indeed, it is somewhat difficult to find
two kinds of paper whose whiteness is identical. And the white that is
got from clear sky reflected in a mirror makes the white of any object
look positively dirty.
Without examining any true colors at all we have already collected a
variety of shades. And this variety grows when we remember all of the
various grays which are darker than the whites but lighter than the
blacks. Von Kries, the German physiologist, found that there were two
hundred and four different shades of gray between the blackest of black
paper and the whitest of white paper. And Kulper, the psychologist,
estimated that the best visible black is a thousand times darker than
the best visible white.
As soon as the true colors are added to the blacks and whites and
grays, the possible visual sensations begin to multiply almost
limitlessly. There are literally thousands of reds: dull reds, bright
reds, yellowish reds, bluish reds. And there are bluish greens,
greenish blues, yellowish greens and greenish yellows. But there is a
limit to these color combinations. There are no reddish greens, no
greenish reds, no yellowish blues and no bluish yellows.
COMMON ABNORMALITIES OF VISION
The astonishingly wide variation of hues and tints and chromas is
visible to the majority of human beings. There is a large class,
however, whose visual range is much narrower. About three percent of
the male population is known to be partially color blind, that is
insensitive to certain visual stimuli. To such individuals blue and
yellow appear as they do to persons with normal color vision; but they
see both red and green as grey, greenish yellow and orange as greyish
yellow, and bluish green and purple as greyish blue. Partial color
blindness is hereditary and although it usually occurs only in males,
it is transmitted by females. Thus a partially color blind man may have
both sons and daughters who are color normal. All of the children of
his sons may also have normal color vision, but the male offspring of
his daughters will be partially color blind.
There are also a number of individuals who are totally color blind,
who see no colors at all. Total color blindness is also hereditary and
is also more prevalent among males than among females, but it is much
rarer than partial color blindness and should be confused neither with
that nor with true blindness. Blind persons see neither colors nor
blacks nor whites nor greys. As Helmholtz put it they “see things in
the same way in which we ourselves see what is behind our backs; that
is to say, they do not see at all.” But totally color blind persons
can see; in a dim light they can see exceptionally well. They can
distinguish objects visually as well as persons with normal eyes, but
for them these objects never possess any color. They always appear grey.
The two forms of color blindness seem more creditable when we realize
that everyone is often either partially or totally color blind. All
of us are partially color blind to objects which we see in indirect
vision, or “out of the corner of the eye.” Many of us, of course, never
realize this deficiency, because we usually pay very little attention
to our indirect vision. If an object interests us we immediately turn
our eyes toward it and focus them upon it and its colors become clear.
But if you will hold an orange or a greenish blue pencil parallel to
and about a foot away from your right ear while your eyes are steadily
focused directly in front of you, and move the pencil gradually until
it is directly in front of your nose, you will find that at the side
of your eye the orange pencil looks only yellow and the greenish blue
pencil only blue. The red and green do not appear until the pencil is
almost within the focus of your eyes. It is only at the very center
then that the eye is color normal. It is partially color blind at the
sides. And it is always totally color blind, of course, in the dark.
If we wake up suddenly on a black night or go quickly from a brightly
lighted room into one that is much darker, we at first seem to be
quite blind--to be incapable of distinguishing anything. Gradually,
however, our eyes become accustomed to the darkness--the psychologists
say that they become dark adapted, and we can make out the outlines of
familiar objects, can see that parts of the room are lighter and parts
darker than others. But we cannot distinguish any colors. We do not
even see any clear blacks or whites. Everything appears grey. And that
is the way the whole world in daylight as well as in darkness looks to
the totally color blind--as a series of darker or lighter greys.
The inability to distinguish the hues of colors is not the only thing
which differentiates the way we see in the dark from the way we see in
daylight. We have already noted the fact that under good illumination
the center of the eye is the area of clearest vision. Those objects
upon which our eyes are focused are the ones which appear clearest to
us. Offhand we would suspect that the same principle held in the dark.
Yet it is very easy to demonstrate that it does not. Some night when
you are out of doors look up at the sky and select one small isolated
star and remember carefully just where it is. Then try to focus your
eye upon it. You will find that this is impossible. As soon as you
stare directly at it it disappears, but reappears as soon as you search
for it. This process can be continued indefinitely--a disappearing and
reappearing which is so rapid that the star actually seems to twinkle.
Whenever you look directly at it it is gone, but as soon as you
shift your eyes ever so slightly it is back again. Carefully verified
experiments which elaborate this simple experience have convinced
psychologists of the fact that at night all eyes are completely blind
at the center where in daylight they have the clearest vision. And
totally color blind eyes show this same deficiency in daylight as well
as in the dark. They twitch continually when their possessors attempt
to read.
So much for the psychological side of visual sensations. If we wish an
explanation of them, of their variety and of their peculiarities, we
must turn once more to anatomy and physiology.
HOW WE SEE IN THE LIGHT AND IN THE DARK
The retina of the eye contains a quantity of microscopic structures,
some of which may be roughly described as rods, others as cones. The
cones are scattered over the entire retina but are thickest at the very
center. The rods have about the same distribution except that they
are entirely lacking at the center. From pathological cases and from
histology the function of these tiny structures has been determined.
A human eye which contains no rods has never been discovered but the
eyes of fowls and pigeons show this defect, and these animals are
apparently quite blind at night. All of their activities are carried
on in the daylight. Hens do not even lay eggs in total darkness.
Conversely the retinas of nocturnal animals, such as bats and owls and
moles, are almost entirely lacking in cones but are richly supplied
with rods. These and similar findings, together with the psychological
differences of night and day vision, have led psychologists and
biologists alike to conclude that the rods and cones, although they
are very similar in structure, serve two very different functions. The
cones provide us with daylight vision, apparently, while the rods,
alone, are responsible for the manner in which we see in the dark. The
rods are completely inactive in daylight but begin to respond to weak
stimuli as soon as twilight (real or artificial) sets in. And the cones
which are reacting continuously during every second that it is light,
become functionally useless in the dark.
The cones alone are responsible for true colors. Many theories have
been advanced to explain their functioning, but they are too long and
too complicated to be reviewed here. This much can be stated, however;
only three photo-chemical substances reacting to light produce all
of our many different hues. The same substance reacting in different
ways gives us both red and green, another both blue and yellow, and a
third both black and white. When more than one substance responds to
stimulation we get the intermediate colors which resemble one or more
of these primary colors, for instance, purple which resembles both blue
and red, and orange which is like both red and yellow. In normal eyes
all three substances are found only at the center and consequently it
is only at the center that all colors are visible. In partially color
blind eyes the red-green substance is absent from the center as well as
the periphery and the partially color blind, therefore, can see only
the colors which contain either yellow or blue. In the absence of blue
or yellow stimuli they see only grey. The totally color blind eye is
completely deficient in cones. The totally color blind use their rods
for daylight as well as dark vision.
THE IMPORTANCE OF THE SENSE OF SMELL
We have spent so much time on visual and tactual sensations because
they represent the two senses which have been investigated most
thoroughly on the physical and biological side. We know not only just
what these groups of sensations are psychologically but how they are
physically and biologically produced. Vision has another claim to
careful study. It, along with audition, is known as a higher sense
and is used more by civilized man than the lower senses of touch,
taste and smell. We depend upon our eyes and ears as guides throughout
all of our practical life and they are the two senses which have the
highest biological development. Aside from their original function of
orientation, civilization has forced them to serve two still higher
purposes. Our eyes and ears are responsible both for the language which
we use in conversation and for our two special forms of culture--art
and music. We have no highly developed gustatory or olfactory art and
although both of these senses are very important in our daily lives,
we never use them as conscious means of communication. Yet viewed in
relation to the evolution of the race, smell is the most important of
all our senses. In the extension of the olfactory organs of the reptile
we find the first hint of the development of a brain. And in all
animals which live on the land the sense of smell is highly specialized.
Fish have no real olfactory sensations. The piscatorial organ which
corresponds to the mammalian nose is really an organ of taste.
Even animals which spend the greatest part of their lives in the
water--whales, dolphins and seals--have very rudimentary olfactory
organs and probably no real sensations of smell. Birds, also, contrary
to common opinion, have a very poor sense of smell and exceedingly
efficient eyes. The power which is usually attributed to their
olfactory sensitivity is actually due to their extraordinarily keen
sight. It has been proven by experiments that if a decaying animal
carcass is carefully concealed carrion birds will pass directly by it
without pausing to investigate. In all animals, however, who habitually
live upon the ground, olfactory experiences are remarkably numerous and
varied. It is easy to verify this fact by observing the behavior of
insects and any four-footed mammals, especially dogs. But it is hard to
believe that human beings are equally sensitive to odors. Yet they can
be.
The human olfactory sense has been extensively investigated but at the
present time no one has been able to state the exact number of smells
which the human nostrils are capable of detecting. The chief difficulty
lies in the fact that while the tactual and visual senses, for example,
are physically limited, new odorous stimuli are being discovered every
day. Each slightly different chemical compound produces a new odor and
each new species of plant life carries its own typical smell. Already
there is reasonable experimental ground for assuming that there are
sensations from all of the other sense departments put together.
There are two principal reasons why we are generally unaware of this
wealth of olfactory experiences. The first is that man habitually walks
on two feet so that his nose, compared to that of other mammals, is
very far from the ground and smells have a tendency to cling to the
ground. Consequently, those smell stimuli which do reach his nostrils
are very weak by the time they arrive there and are, therefore,
generally ignored in favor of the more insistent visual and auditory
tactual stimuli. In the second place, the most frequent and the
strongest odors we experience we customarily ascribe to our sense of
taste. We speak of the taste of our food when we are actually referring
to its smell.
It is very easy to prove by experiment how limited is our sense of
taste but we even have a very strong hint of the fact during our
everyday life, or rather during that part of our everyday life when
we are afflicted by a severe cold in the head. At such times we think
that even the most savory meal has very little taste. Yet common sense
should tell us that our tongues, which in adult life contain almost
all of the sense organs of taste, are not seriously impaired by a bad
cold. We should know that it is our noses, in which the olfactory organ
is situated, which are really affected. It is the sense of smell which
we habitually confuse with that of taste which is weakened. It is not
entirely out of commission, however. There is a small passage at the
back of the mouth, leading to the nose, of which we are disagreeably
conscious when we choke. In swallowing, air laden with odorous
particles is pushed up through this passage, the posterior nares of
the nostrils are immediately stimulated and smell is experienced. This
arrangement is quite evident to us when we take medicine which has a
particularly disagreeable odor. Holding the nose helps a great deal
until the dose is actually swallowed. If you should continue to hold
your nose and, instead of swallowing, rinse your mouth thoroughly,
you would be surprised to find how very little unpleasant “taste” the
medicine contained. A rather agreeable sweetness might be all that
remained.
THE TRUE SENSE OF TASTE
When all odor is completely eliminated by stopping the nostrils
with cotton and the surface of the tongue is stimulated directly,
it has been discovered that there are only four fundamental tastes,
sour, salt, sweet and bitter. A particular region of the tongue is
responsible for each of these four tastes. It is very easy to find
these specialized parts for, while the functional organ of the nose
is so securely hidden that it is almost impossible to stimulate it
directly, the gustatory organs are visible to the naked eye. They are
contained in the tiny bright red spots, or papillae, that dot the
duller surface of the tongue everywhere except in the center. Although
any single papilla is apt to contain several kinds of taste buds and
may, therefore, be sensitive to more than one taste, and although the
buds which respond to salt are fairly equally distributed over the
sensitive area of the tongue, those which react to sweet, sour and
bitter are grouped on different regions. Language recognizes this
distribution.
We describe as a sweet expression one in which the lips are drawn
toward the tip of the tongue and the tip, itself, is flattened out.
The taste buds which respond to sweet stimuli are found clustered at
the tip of the tongue. In a sour expression the lips are drawn back
from the tip of the tongue and down toward the sides. And the sour
taste buds are thickest on the sides of the tongue. When a face wears
a bitter expression the tongue itself is pulled back until it is in
contact with the roof of the mouth. And the bitter taste buds are found
almost exclusively at the rear of the tongue.
Testing these three facial expressions before the mirror will afford
you a little innocent amusement, but remembering what they represent
will help you to get the full effect of desirable tastes and to avoid
the disagreeable qualities of others. A bitter tablet, for example,
should not be placed at the rear of the tongue where you would get
the full benefit of its bitterness, but rather in the center which is
relatively insensitive to any taste.
The manner in which children lick a stick of candy shows that they
realize unconsciously how they can make the most of its sweetness. The
taste buds also explain another habit of children which is usually
frowned upon by their elders--that of taking large mouthfuls. Children
have many more taste buds than adults. They are distributed not only
over the whole surface of the tongue but on the insides of the cheeks
as well. Consequently when children stuff their mouths until their jaws
bulge, they actually get a great many more gustatory sensations than
when they have only a dainty morsel on their tongues. If the taste buds
in the cheeks did not atrophy early in life, there would probably be
nothing ill mannered about large mouthfuls. As it is, large mouthfuls
are quite useless to adults. The food has to be directly on their
tongues before they can taste it. So, forgetting the days when bulging
cheeks were so delightful, adults become intolerant of a habit which
was once both pleasant and useful.
THE COMPLEXITY OF OUR PERCEPTIONS
Because it is possible to isolate particular sensations and study them
in detail, as we have attempted to do here, it must not be assumed
that we customarily experience them in so simple a manner. Even at
birth the human nervous system is a tremendously complicated affair.
There are cross connections among the senses. From the very first most
of our sensations seem to us completely bound up with other processes.
A pure sensation is a very rare occurrence. A color is nearly always
the color of something--of cloth or leather or paper or liquid. All of
the objects which have colors have textures also. They look rough or
smooth or glossy or dull. And the color and texture seem inalterably
mixed together. It is only when we look at a rainbow or the rays of
a spectroscope that we see a color which does not appear to be an
integral part of some object.
Tones seem to belong less to the objects which produce them--to exist
by themselves to a greater degree. Yet it is much more difficult to
produce a simple tone than a pure color. In this case the trouble
lies not so much with the nervous system as in the physical stimulus
itself. There are not as many audible tones as there are discernible
colors and odors, but there are some eleven thousand of them. The tone
got from a musical instrument is not, however, a simple tone or a pure
sensation. It is a combination of many tones, some of which are more
intense than others. These extra tones or partials are produced by
the musical instrument itself and they cannot be eliminated because a
musical instrument is essentially a complicated vibrating body. With
each vibration it produces over-tones as well as a principal tone. It
is the different intensities of the partial tones which give timbre to
instruments. It is by their characteristic timbres that we are able to
distinguish a G struck on a piano from the G of an organ or a violin or
a saxophone.
Because it is so difficult to produce simple tones, psychologists have
been unable to discover a great deal about our sense of audition. The
physical side of sound has been adequately investigated, but we have to
resort to musical terminology when we try to describe the sensations
which are produced.
We have already discovered, then, in the case of the three lower
senses, our perceptions appear so unified that we seldom realize that
they are complex. Wetness seems to be a unique experience until we
recognize that it is composed of cold and pressure. So completely
blended are our tastes and smells that a severe cold in the head is
required for their conscious separation. And psychologists had to wait
for years, until a soldier had a strange cortical injury, before they
learned how complicated a process is tactual localization.
LOCALIZATION ON THE SKIN
Localizing a spot on the surface of the skin seems to be the very
simplest of matters. An itch occurs on the hand and automatically we
scratch it. Sometimes, it is true, the itch comes in the small of the
back and we cannot quite reach it. But we can at least point out its
approximate position to some other person. Both the scratching and
the pointing seem to be as simple as reflex actions. This apparent
simplicity led the psychologist Loetze to believe that every single
spot on the body had a special attribute which he called a “local
sign.” According to his doctrine we know exactly where we have been
touched the instant that we are aware of the touch itself. Henri,
another psychologist, discovered, however, that if he was stimulated on
the skin when his eyes were closed and tried to locate the exact spot
before he opened his eyes again, he made large errors of localization
and the errors were as great on the finger as on the forearm. This
discovery cast grave doubt on the doctrine of the local sign.
During the late war two psychologists, Gelb and Goldstein, were
attached to a German army hospital. One day a patient was brought in,
who had had both of his occipital lobes destroyed, but the rest of his
nervous system was still intact. This meant that he had absolutely no
visual cognitions but the rest of his mental functions were unimpaired.
Gelb and Goldstein immediately began to experiment with him and they
got some rather startling results.
If the patient was lying quietly with his eyes shut and was touched
on some part of his body, perhaps his left foot, he knew that he had
been touched but he had no idea of the place. He did not know whether
it was on the leg or the forehead or the chest or the hand. It made no
difference how intense the stimulus was or how long it was continued.
As long as he remained motionless he could not tell where it was.
If, however, he was allowed to move his body as much as he wished, he
could localize the place touched almost exactly but he did it in a very
strange way. He at first wriggled about so that he set his entire body
in motion. Then gradually he would move less and less. If the stimulus
was applied to his right index finger, he would, after a few squirms
of his whole body, move only his trunk, then only his right arm, then
just his forearm, his right hand, his fingers, and finally only the
stimulated finger. Then he could say just where the pressure was felt.
If he was touched in two places at once, as long as he was quiet, he
would feel only one. If the two stimuli happened to be very close
together, for instance both on the same finger, even by wriggling he
could not discover that they were two. But if they were rather widely
separated he could by the proper movements locate first one and then
the other.
When he was allowed to touch the place stimulated, his method was the
same as when he wriggled his body. At first he would run his finger
aimlessly over his skin, gradually bringing it closer and closer to the
stimulated area until the exact spot was hit upon.
These results led Gelb and Goldstein to the conclusion, which was
foreshadowed by Henri, that immediate localization is always a function
of vision. And they agreed with the findings of some rather different
experiments which had been carried on at Cornell University several
years before. The subjects of these experiments had to be real
scientific martyrs. They were required to swallow a rubber tube in
which there was an electric coil. The tube reached from the mouth to
the bottom of the stomach and at intervals there were openings in it
through which the experimenter could send an electric shock. All of
the subjects had the greatest difficulty in locating the shocks; they
could feel them clearly enough but they could not discover in which
part of their digestive tracts they were. A stimulation might be at the
extreme end of the tube and the subject would report that it was in his
thorax. A shock at the esophagus would be referred to the bottom of the
stomach, and so on.
If localization is primarily a matter of vision, these errors are
easily accounted for. No one has a very complete mental picture of the
inside of his own digestive tract. When we localize sensations there we
must do so by reference to the more familiar external body. But since
the sensations are felt internally, not on the outside, it is only
natural that the reference should often be erroneous. Doctors recognize
this. They accept a patient’s statement that he has a pain but they
are not so quick to take his word for its exact location. Instead
they investigate. And when they thump about first at one place then
at another, they are using the same method of localization which Gelb
and Goldstein’s soldier employed when he ran his finger over his body.
Fortunately, this method, though much slower than visual localization,
is usually successful.
Transcriber’s Note:
- Inconsistencies in hyphenation have been standardized.
- Minor punctuation errors have been changed without notice.
- Spelling was retained as in the original except for the following
changes:
Page 21: “spent so much time is” to “spent so much time on”
Page 27: “most of our sensations some” to “most of our sensations
seem”
Page 27: “a pure sensation. It it” to “a pure sensation. It is”
*** END OF THE PROJECT GUTENBERG EBOOK WHAT YOU SHOULD KNOW ABOUT YOUR SENSATIONS ***
Updated editions will replace the previous one—the old editions will
be renamed.
Creating the works from print editions not protected by U.S. copyright
law means that no one owns a United States copyright in these works,
so the Foundation (and you!) can copy and distribute it in the United
States without permission and without paying copyright
royalties. Special rules, set forth in the General Terms of Use part
of this license, apply to copying and distributing Project
Gutenberg™ electronic works to protect the PROJECT GUTENBERG™
concept and trademark. Project Gutenberg is a registered trademark,
and may not be used if you charge for an eBook, except by following
the terms of the trademark license, including paying royalties for use
of the Project Gutenberg trademark. If you do not charge anything for
copies of this eBook, complying with the trademark license is very
easy. You may use this eBook for nearly any purpose such as creation
of derivative works, reports, performances and research. Project
Gutenberg eBooks may be modified and printed and given away—you may
do practically ANYTHING in the United States with eBooks not protected
by U.S. copyright law. Redistribution is subject to the trademark
license, especially commercial redistribution.
START: FULL LICENSE
THE FULL PROJECT GUTENBERG™ LICENSE
PLEASE READ THIS BEFORE YOU DISTRIBUTE OR USE THIS WORK
To protect the Project Gutenberg™ mission of promoting the free
distribution of electronic works, by using or distributing this work
(or any other work associated in any way with the phrase “Project
Gutenberg”), you agree to comply with all the terms of the Full
Project Gutenberg License available with this file or online at
www.gutenberg.org/license.
Section 1. General Terms of Use and Redistributing Project Gutenberg
electronic works
1.A. By reading or using any part of this Project Gutenberg
electronic work, you indicate that you have read, understand, agree to
and accept all the terms of this license and intellectual property
(trademark/copyright) agreement. If you do not agree to abide by all
the terms of this agreement, you must cease using and return or
destroy all copies of Project Gutenberg electronic works in your
possession. If you paid a fee for obtaining a copy of or access to a
Project Gutenberg electronic work and you do not agree to be bound
by the terms of this agreement, you may obtain a refund from the person
or entity to whom you paid the fee as set forth in paragraph 1.E.8.
1.B. “Project Gutenberg” is a registered trademark. It may only be
used on or associated in any way with an electronic work by people who
agree to be bound by the terms of this agreement. There are a few
things that you can do with most Project Gutenberg electronic works
even without complying with the full terms of this agreement. See
paragraph 1.C below. There are a lot of things you can do with Project
Gutenberg electronic works if you follow the terms of this
agreement and help preserve free future access to Project Gutenberg
electronic works. See paragraph 1.E below.
1.C. The Project Gutenberg Literary Archive Foundation (“the
Foundation” or PGLAF), owns a compilation copyright in the collection
of Project Gutenberg electronic works. Nearly all the individual
works in the collection are in the public domain in the United
States. If an individual work is unprotected by copyright law in the
United States and you are located in the United States, we do not
claim a right to prevent you from copying, distributing, performing,
displaying or creating derivative works based on the work as long as
all references to Project Gutenberg are removed. Of course, we hope
that you will support the Project Gutenberg mission of promoting
free access to electronic works by freely sharing Project Gutenberg
works in compliance with the terms of this agreement for keeping the
Project Gutenberg name associated with the work. You can easily
comply with the terms of this agreement by keeping this work in the
same format with its attached full Project Gutenberg License when
you share it without charge with others.
1.D. The copyright laws of the place where you are located also govern
what you can do with this work. Copyright laws in most countries are
in a constant state of change. If you are outside the United States,
check the laws of your country in addition to the terms of this
agreement before downloading, copying, displaying, performing,
distributing or creating derivative works based on this work or any
other Project Gutenberg work. The Foundation makes no
representations concerning the copyright status of any work in any
country other than the United States.
1.E. Unless you have removed all references to Project Gutenberg:
1.E.1. The following sentence, with active links to, or other
immediate access to, the full Project Gutenberg License must appear
prominently whenever any copy of a Project Gutenberg work (any work
on which the phrase “Project Gutenberg” appears, or with which the
phrase “Project Gutenberg” is associated) is accessed, displayed,
performed, viewed, copied or distributed:
This eBook is for the use of anyone anywhere in the United States and most
other parts of the world at no cost and with almost no restrictions
whatsoever. You may copy it, give it away or re-use it under the terms
of the Project Gutenberg™ License included with this eBook or online
at www.gutenberg.org. If you
are not located in the United States, you will have to check the laws
of the country where you are located before using this eBook.
1.E.2. If an individual Project Gutenberg electronic work is
derived from texts not protected by U.S. copyright law (does not
contain a notice indicating that it is posted with permission of the
copyright holder), the work can be copied and distributed to anyone in
the United States without paying any fees or charges. If you are
redistributing or providing access to a work with the phrase “Project
Gutenberg” associated with or appearing on the work, you must comply
either with the requirements of paragraphs 1.E.1 through 1.E.7 or
obtain permission for the use of the work and the Project Gutenberg
trademark as set forth in paragraphs 1.E.8 or 1.E.9.
1.E.3. If an individual Project Gutenberg electronic work is posted
with the permission of the copyright holder, your use and distribution
must comply with both paragraphs 1.E.1 through 1.E.7 and any
additional terms imposed by the copyright holder. Additional terms
will be linked to the Project Gutenberg License for all works
posted with the permission of the copyright holder found at the
beginning of this work.
1.E.4. Do not unlink or detach or remove the full Project Gutenberg
License terms from this work, or any files containing a part of this
work or any other work associated with Project Gutenberg.
1.E.5. Do not copy, display, perform, distribute or redistribute this
electronic work, or any part of this electronic work, without
prominently displaying the sentence set forth in paragraph 1.E.1 with
active links or immediate access to the full terms of the Project
Gutenberg License.
1.E.6. You may convert to and distribute this work in any binary,
compressed, marked up, nonproprietary or proprietary form, including
any word processing or hypertext form. However, if you provide access
to or distribute copies of a Project Gutenberg work in a format
other than “Plain Vanilla ASCII” or other format used in the official
version posted on the official Project Gutenberg website
(www.gutenberg.org), you must, at no additional cost, fee or expense
to the user, provide a copy, a means of exporting a copy, or a means
of obtaining a copy upon request, of the work in its original “Plain
Vanilla ASCII” or other form. Any alternate format must include the
full Project Gutenberg License as specified in paragraph 1.E.1.
1.E.7. Do not charge a fee for access to, viewing, displaying,
performing, copying or distributing any Project Gutenberg works
unless you comply with paragraph 1.E.8 or 1.E.9.
1.E.8. You may charge a reasonable fee for copies of or providing
access to or distributing Project Gutenberg electronic works
provided that:
• You pay a royalty fee of 20% of the gross profits you derive from
the use of Project Gutenberg works calculated using the method
you already use to calculate your applicable taxes. The fee is owed
to the owner of the Project Gutenberg trademark, but he has
agreed to donate royalties under this paragraph to the Project
Gutenberg Literary Archive Foundation. Royalty payments must be paid
within 60 days following each date on which you prepare (or are
legally required to prepare) your periodic tax returns. Royalty
payments should be clearly marked as such and sent to the Project
Gutenberg Literary Archive Foundation at the address specified in
Section 4, “Information about donations to the Project Gutenberg
Literary Archive Foundation.”
• You provide a full refund of any money paid by a user who notifies
you in writing (or by e-mail) within 30 days of receipt that s/he
does not agree to the terms of the full Project Gutenberg™
License. You must require such a user to return or destroy all
copies of the works possessed in a physical medium and discontinue
all use of and all access to other copies of Project Gutenberg™
works.
• You provide, in accordance with paragraph 1.F.3, a full refund of
any money paid for a work or a replacement copy, if a defect in the
electronic work is discovered and reported to you within 90 days of
receipt of the work.
• You comply with all other terms of this agreement for free
distribution of Project Gutenberg™ works.
1.E.9. If you wish to charge a fee or distribute a Project
Gutenberg™ electronic work or group of works on different terms than
are set forth in this agreement, you must obtain permission in writing
from the Project Gutenberg Literary Archive Foundation, the manager of
the Project Gutenberg™ trademark. Contact the Foundation as set
forth in Section 3 below.
1.F.
1.F.1. Project Gutenberg volunteers and employees expend considerable
effort to identify, do copyright research on, transcribe and proofread
works not protected by U.S. copyright law in creating the Project
Gutenberg™ collection. Despite these efforts, Project Gutenberg™
electronic works, and the medium on which they may be stored, may
contain “Defects,” such as, but not limited to, incomplete, inaccurate
or corrupt data, transcription errors, a copyright or other
intellectual property infringement, a defective or damaged disk or
other medium, a computer virus, or computer codes that damage or
cannot be read by your equipment.
1.F.2. LIMITED WARRANTY, DISCLAIMER OF DAMAGES - Except for the “Right
of Replacement or Refund” described in paragraph 1.F.3, the Project
Gutenberg Literary Archive Foundation, the owner of the Project
Gutenberg™ trademark, and any other party distributing a Project
Gutenberg™ electronic work under this agreement, disclaim all
liability to you for damages, costs and expenses, including legal
fees. YOU AGREE THAT YOU HAVE NO REMEDIES FOR NEGLIGENCE, STRICT
LIABILITY, BREACH OF WARRANTY OR BREACH OF CONTRACT EXCEPT THOSE
PROVIDED IN PARAGRAPH 1.F.3. YOU AGREE THAT THE FOUNDATION, THE
TRADEMARK OWNER, AND ANY DISTRIBUTOR UNDER THIS AGREEMENT WILL NOT BE
LIABLE TO YOU FOR ACTUAL, DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE OR
INCIDENTAL DAMAGES EVEN IF YOU GIVE NOTICE OF THE POSSIBILITY OF SUCH
DAMAGE.
1.F.3. LIMITED RIGHT OF REPLACEMENT OR REFUND - If you discover a
defect in this electronic work within 90 days of receiving it, you can
receive a refund of the money (if any) you paid for it by sending a
written explanation to the person you received the work from. If you
received the work on a physical medium, you must return the medium
with your written explanation. The person or entity that provided you
with the defective work may elect to provide a replacement copy in
lieu of a refund. If you received the work electronically, the person
or entity providing it to you may choose to give you a second
opportunity to receive the work electronically in lieu of a refund. If
the second copy is also defective, you may demand a refund in writing
without further opportunities to fix the problem.
1.F.4. Except for the limited right of replacement or refund set forth
in paragraph 1.F.3, this work is provided to you ‘AS-IS’, WITH NO
OTHER WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PURPOSE.
1.F.5. Some states do not allow disclaimers of certain implied
warranties or the exclusion or limitation of certain types of
damages. If any disclaimer or limitation set forth in this agreement
violates the law of the state applicable to this agreement, the
agreement shall be interpreted to make the maximum disclaimer or
limitation permitted by the applicable state law. The invalidity or
unenforceability of any provision of this agreement shall not void the
remaining provisions.
1.F.6. INDEMNITY - You agree to indemnify and hold the Foundation, the
trademark owner, any agent or employee of the Foundation, anyone
providing copies of Project Gutenberg™ electronic works in
accordance with this agreement, and any volunteers associated with the
production, promotion and distribution of Project Gutenberg™
electronic works, harmless from all liability, costs and expenses,
including legal fees, that arise directly or indirectly from any of
the following which you do or cause to occur: (a) distribution of this
or any Project Gutenberg work, (b) alteration, modification, or
additions or deletions to any Project Gutenberg work, and (c) any
Defect you cause.
Section 2. Information about the Mission of Project Gutenberg
Project Gutenberg is synonymous with the free distribution of
electronic works in formats readable by the widest variety of
computers including obsolete, old, middle-aged and new computers. It
exists because of the efforts of hundreds of volunteers and donations
from people in all walks of life.
Volunteers and financial support to provide volunteers with the
assistance they need are critical to reaching Project Gutenberg’s
goals and ensuring that the Project Gutenberg collection will
remain freely available for generations to come. In 2001, the Project
Gutenberg Literary Archive Foundation was created to provide a secure
and permanent future for Project Gutenberg and future
generations. To learn more about the Project Gutenberg Literary
Archive Foundation and how your efforts and donations can help, see
Sections 3 and 4 and the Foundation information page at www.gutenberg.org.
Section 3. Information about the Project Gutenberg Literary Archive Foundation
The Project Gutenberg Literary Archive Foundation is a non-profit
501(c)(3) educational corporation organized under the laws of the
state of Mississippi and granted tax exempt status by the Internal
Revenue Service. The Foundation’s EIN or federal tax identification
number is 64-6221541. Contributions to the Project Gutenberg Literary
Archive Foundation are tax deductible to the full extent permitted by
U.S. federal laws and your state’s laws.
The Foundation’s business office is located at 41 Watchung Plaza #516,
Montclair NJ 07042, USA, +1 (862) 621-9288. Email contact links and up
to date contact information can be found at the Foundation’s website
and official page at www.gutenberg.org/contact
Section 4. Information about Donations to the Project Gutenberg
Literary Archive Foundation
Project Gutenberg™ depends upon and cannot survive without widespread
public support and donations to carry out its mission of
increasing the number of public domain and licensed works that can be
freely distributed in machine-readable form accessible by the widest
array of equipment including outdated equipment. Many small donations
($1 to $5,000) are particularly important to maintaining tax exempt
status with the IRS.
The Foundation is committed to complying with the laws regulating
charities and charitable donations in all 50 states of the United
States. Compliance requirements are not uniform and it takes a
considerable effort, much paperwork and many fees to meet and keep up
with these requirements. We do not solicit donations in locations
where we have not received written confirmation of compliance. To SEND
DONATIONS or determine the status of compliance for any particular state
visit www.gutenberg.org/donate.
While we cannot and do not solicit contributions from states where we
have not met the solicitation requirements, we know of no prohibition
against accepting unsolicited donations from donors in such states who
approach us with offers to donate.
International donations are gratefully accepted, but we cannot make
any statements concerning tax treatment of donations received from
outside the United States. U.S. laws alone swamp our small staff.
Please check the Project Gutenberg web pages for current donation
methods and addresses. Donations are accepted in a number of other
ways including checks, online payments and credit card donations. To
donate, please visit: www.gutenberg.org/donate.
Section 5. General Information About Project Gutenberg electronic works
Professor Michael S. Hart was the originator of the Project
Gutenberg concept of a library of electronic works that could be
freely shared with anyone. For forty years, he produced and
distributed Project Gutenberg eBooks with only a loose network of
volunteer support.
Project Gutenberg eBooks are often created from several printed
editions, all of which are confirmed as not protected by copyright in
the U.S. unless a copyright notice is included. Thus, we do not
necessarily keep eBooks in compliance with any particular paper
edition.
Most people start at our website which has the main PG search
facility: www.gutenberg.org.
This website includes information about Project Gutenberg,
including how to make donations to the Project Gutenberg Literary
Archive Foundation, how to help produce our new eBooks, and how to
subscribe to our email newsletter to hear about new eBooks.
