Chapter XIV — CONCLUDING REMARKS AND SUMMARY

The three leading principles which have determined the chief movements of
expression—Their inheritance—On the part which the will and
intention have played in the acquirement of various expressions—The
instinctive recognition of expression—The bearing of our subject on
the specific unity of the races of man—On the successive acquirement
of various expressions by the progenitors of man—The importance of
expression—Conclusion.

I have now described, to the best of my ability, the chief expressive
actions in man, and in some few of the lower animals. I have also
attempted to explain the origin or development of these actions through
the three principles given in the first chapter. The first of these
principles is, that movements which are serviceable in gratifying some
desire, or in relieving some sensation, if often repeated, become so
habitual that they are performed, whether or not of any service, whenever
the same desire or sensation is felt, even in a very weak degree.

Our second principle is that of antithesis. The habit of voluntarily
performing opposite movements under opposite impulses has become firmly
established in us by the practice of our whole lives. Hence, if certain
actions have been regularly performed, in accordance with our first
principle, under a certain frame of mind, there will be a strong and
involuntary tendency to the performance of directly opposite actions,
whether or not these are of any use, under the excitement of an opposite
frame of mind.

Our third principle is the direct action of the excited nervous system on
the body, independently of the will, and independently, in large part, of
habit. Experience shows that nerve-force is generated and set free
whenever the cerebro-spinal system is excited. The direction which this
nerve-force follows is necessarily determined by the lines of connection
between the nerve-cells, with each other and with various parts of the
body. But the direction is likewise much influenced by habit; inasmuch as
nerve-force passes readily along accustomed channels.

The frantic and senseless actions of an enraged man may be attributed in
part to the undirected flow of nerve-force, and in part to the effects of
habit, for these actions often vaguely represent the act of striking. They
thus pass into gestures included under our first principle; as when an
indignant man unconsciously throws himself into a fitting attitude for
attacking his opponent, though without any intention of making an actual
attack. We see also the influence of habit in all the emotions and
sensations which are called exciting; for they have assumed this character
from having habitually led to energetic action; and action affects, in an
indirect manner, the respiratory and circulatory system; and the latter
reacts on the brain. Whenever these emotions or sensations are even
slightly felt by us, though they may not at the time lead to any exertion,
our whole system is nevertheless disturbed through the force of habit and
association. Other emotions and sensations are called depressing, because
they have not habitually led to energetic action, excepting just at first,
as in the case of extreme pain, fear, and grief, and they have ultimately
caused complete exhaustion; they are consequently expressed chiefly by
negative signs and by prostration. Again, there are other emotions, such
as that of affection, which do not commonly lead to action of any kind,
and consequently are not exhibited by any strongly marked outward signs.
Affection indeed, in as far as it is a pleasurable sensation, excites the
ordinary signs of pleasure.

On the other hand, many of the effects due to the excitement of the
nervous system seem to be quite independent of the flow of nerve-force
along the channels which have been rendered habitual by former exertions
of the will. Such effects, which often reveal the state of mind of the
person thus affected, cannot at present be explained; for instance, the
change of colour in the hair from extreme terror or grief,—the cold
sweat and the trembling of the muscles from fear,—the modified
secretions of the intestinal canal,—and the failure of certain
glands to act.

Notwithstanding that much remains unintelligible in our present subject,
so many expressive movements and actions can be explained to a certain
extent through the above three principles, that we may hope hereafter to
see all explained by these or by closely analogous principles.

Actions of all kinds, if regularly accompanying any state of the mind, are
at once recognized as expressive. These may consist of movements of any
part of the body, as the wagging of a dog’s tail, the shrugging of a man’s
shoulders, the erection of the hair, the exudation of perspiration, the
state of the capillary circulation, laboured breathing, and the use of the
vocal or other sound-producing instruments. Even insects express anger,
terror, jealousy, and love by their stridulation. With man the respiratory
organs are of especial importance in expression, not only in a direct, but
in a still higher degree in an indirect manner.

Few points are more interesting in our present subject than the
extraordinarily complex chain of events which lead to certain expressive
movements. Take, for instance, the oblique eyebrows of a man suffering
from grief or anxiety. When infants scream loudly from hunger or pain, the
circulation is affected, and the eyes tend to become gorged with blood:
consequently the muscles surrounding the eyes are strongly contracted as a
protection: this action, in the course of many generations, has become
firmly fixed and inherited: but when, with advancing years and culture,
the habit of screaming is partially repressed, the muscles round the eyes
still tend to contract, whenever even slight distress is felt: of these
muscles, the pyramidals of the nose are less under the control of the will
than are the others and their contraction can be checked only by that of
the central fasciae of the frontal muscle: these latter fasciae draw up
the inner ends of the eyebrows, and wrinkle the forehead in a peculiar
manner, which we instantly recognize as the expression of grief or
anxiety. Slight movements, such as these just described, or the scarcely
perceptible drawing down of the corners of the mouth, are the last
remnants or rudiments of strongly marked and intelligible movements. They
are as full of significance to us in regard to expression, as are ordinary
rudiments to the naturalist in the classification and genealogy of organic
beings.

That the chief expressive actions, exhibited by man and by the lower
animals, are now innate or inherited,—that is, have not been learnt
by the individual,—is admitted by every one. So little has learning
or imitation to do with several of them that they are from the earliest
days and throughout life quite beyond our control; for instance, the
relaxation of the arteries of the skin in blushing, and the increased
action of the heart in anger. We may see children, only two or three years
old, and even those born blind, blushing from shame; and the naked scalp
of a very young infant reddens from passion. Infants scream from pain
directly after birth, and all their features then assume the same form as
during subsequent years. These facts alone suffice to show that many of
our most important expressions have not been learnt; but it is remarkable
that some, which are certainly innate, require practice in the individual,
before they are performed in a full and perfect manner; for instance,
weeping and laughing. The inheritance of most of our expressive actions
explains the fact that those born blind display them, as I hear from the
Rev. R. H. Blair, equally well with those gifted with eyesight. We can
thus also understand the fact that the young and the old of widely
different races, both with man and animals, express the same state of mind
by the same movements.

We are so familiar with the fact of young and old animals displaying their
feelings in the same manner, that we hardly perceive how remarkable it is
that a young puppy should wag its tail when pleased, depress its ears and
uncover its canine teeth when pretending to be savage, just like an old
dog; or that a kitten should arch its little back and erect its hair when
frightened and angry, like an old cat. When, however, we turn to less
common gestures in ourselves, which we are accustomed to look at as
artificial or conventional,—such as shrugging the shoulders, as a
sign of impotence, or the raising the arms with open hands and extended
fingers, as a sign of wonder,—we feel perhaps too much surprise at
finding that they are innate. That these and some other gestures are
inherited, we may infer from their being performed by very young children,
by those born blind, and by the most widely distinct races of man. We
should also bear in mind that new and highly peculiar tricks, in
association with certain states of the mind, are known to have arisen in
certain individuals, and to have been afterwards transmitted to their
offspring, in some cases, for more than one generation.

Certain other gestures, which seem to us so natural that we might easily
imagine that they were innate, apparently have been learnt like the words
of a language. This seems to be the case with the joining of the uplifted
hands, and the turning up of the eyes, in prayer. So it is with kissing as
a mark of affection; but this is innate, in so far as it depends on the
pleasure derived from contact with a beloved person. The evidence with
respect to the inheritance of nodding and shaking the head, as signs of
affirmation and negation, is doubtful; for they are not universal, yet
seem too general to have been independently acquired by all the
individuals of so many races.

We will now consider how far the will and consciousness have come into
play in the development of the various movements of expression. As far as
we can judge, only a few expressive movements, such as those just referred
to, are learnt by each individual; that is, were consciously and
voluntarily performed during the early years of life for some definite
object, or in imitation of others, and then became habitual. The far
greater number of the movements of expression, and all the more important
ones, are, as we have seen, innate or inherited; and such cannot be said
to depend on the will of the individual. Nevertheless, all those included
under our first principle were at first voluntarily performed for a
definite object,—namely, to escape some danger, to relieve some
distress, or to gratify some desire. For instance, there can hardly be a
doubt that the animals which fight with their teeth, have acquired the
habit of drawing back their ears closely to their heads, when feeling
savage, from their progenitors having voluntarily acted in this manner in
order to protect their ears from being torn by their antagonists; for
those animals which do not fight with their teeth do not thus express a
savage state of mind. We may infer as highly probable that we ourselves
have acquired the habit of contracting the muscles round the eyes, whilst
crying gently, that is, without the utterance of any loud sound, from our
progenitors, especially during infancy, having experienced, during the act
of screaming, an uncomfortable sensation in their eyeballs. Again, some
highly expressive movements result from the endeavour to cheek or prevent
other expressive movements; thus the obliquity of the eyebrows and the
drawing down of the corners of the mouth follow from the endeavour to
prevent a screaming-fit from coming on, or to cheek it after it has come
on. Here it is obvious that the consciousness and will must at first have
come into play; not that we are conscious in these or in other such cases
what muscles are brought into action, any more than when we perform the
most ordinary voluntary movements.

With respect to the expressive movements due to the principle of
antithesis, it is clear that the will has intervened, though in a remote
and indirect manner. So again with the movements coming under our third
principle; these, in as far as they are influenced by nerve-force readily
passing along habitual channels, have been determined by former and
repeated exertions of the will. The effects indirectly due to this latter
agency are often combined in a complex manner, through the force of habit
and association, with those directly resulting from the excitement of the
cerebro-spinal system. This seems to be the case with the increased action
of the heart under the influence of any strong emotion. When an animal
erects its hair, assumes a threatening attitude, and utters fierce sounds,
in order to terrify an enemy, we see a curious combination of movements
which were originally voluntary with those that are involuntary. It is,
however, possible that even strictly involuntary actions, such as the
erection of the hair, may have been affected by the mysterious power of
the will.

Some expressive movements may have arisen spontaneously, in association
with certain states of the mind, like the tricks lately referred to, and
afterwards been inherited. But I know of no evidence rendering this view
probable.

The power of communication between the members of the same tribe by means
of language has been of paramount importance in the development of man;
and the force of language is much aided by the expressive movements of the
face and body. We perceive this at once when we converse on an important
subject with any person whose face is concealed. Nevertheless there are no
grounds, as far as I can discover, for believing that any muscle has been
developed or even modified exclusively for the sake of expression. The
vocal and other sound-producing organs, by which various expressive noises
are produced, seem to form a partial exception; but I have elsewhere
attempted to show that these organs were first developed for sexual
purposes, in order that one sex might call or charm the other. Nor can I
discover grounds for believing that any inherited movement, which now
serves as a means of expression, was at first voluntarily and consciously
performed for this special purpose,—like some of the gestures and
the finger-language used by the deaf and dumb. On the contrary, every true
or inherited movement of expression seems to have had some natural and
independent origin. But when once acquired, such movements may be
voluntarily and consciously employed as a means of communication. Even
infants, if carefully attended to, find out at a very early age that their
screaming brings relief, and they soon voluntarily practise it. We may
frequently see a person voluntarily raising his eyebrows to express
surprise, or smiling to express pretended satisfaction and acquiescence. A
man often wishes to make certain gestures conspicuous or demonstrative,
and will raise his extended arms with widely opened fingers above his
head, to show astonishment, or lift his shoulders to his ears, to show
that he cannot or will not do something. The tendency to such movements
will be strengthened or increased by their being thus voluntarily and
repeatedly performed; and the effects may be inherited.

It is perhaps worth consideration whether movements at first used only by
one or a few individuals to express a certain state of mind may not
sometimes have spread to others, and ultimately have become universal,
through the power of conscious and unconscious imitation. That there
exists in man a strong tendency to imitation, independently of the
conscious will, is certain. This is exhibited in the most extraordinary
manner in certain brain diseases, especially at the commencement of
inflammatory softening of the brain, and has been called the “echo sign.”
Patients thus affected imitate, without understanding every absurd gesture
which is made, and every word which is uttered near them, even in a
foreign language.[1401] In the case of animals, the jackal and
wolf have learnt under confinement to imitate the barking of the dog. How
the barking of the dog, which serves to express various emotions and
desires, and which is so remarkable from having been acquired since the
animal was domesticated, and from being inherited in different degrees by
different breeds, was first learnt we do not know; but may we not suspect
that imitation has had something to do with its acquisition, owing to dogs
having long lived in strict association with so loquacious an animal as
man?

In the course of the foregoing remarks and throughout this volume, I have
often felt much difficulty about the proper application of the terms,
will, consciousness, and intention. Actions, which were at first
voluntary, soon became habitual, and at last hereditary, and may then be
performed even in opposition to the will. Although they often reveal the
state of the mind, this result was not at first either intended or
expected. Even such words as that “certain movements serve as a means of
expression,” are apt to mislead, as they imply that this was their primary
purpose or object. This, however, seems rarely or never to have been the
case; the movements having been at first either of some direct use, or the
indirect effect of the excited state of the sensorium. An infant may
scream either intentionally or instinctively to show that it wants food;
but it has no wish or intention to draw its features into the peculiar
form which so plainly indicates misery; yet some of the most
characteristic expressions exhibited by man are derived from the act of
screaming, as has been explained.

Although most of our expressive actions are innate or instinctive, as is
admitted by everyone, it is a different question whether we have any
instinctive power of recognizing them. This has generally been assumed to
be the case; but the assumption has been strongly controverted by M.
Lemoine.[1402] Monkeys soon learn to distinguish, not
only the tones of voice of their masters, but the expression of their
faces, as is asserted by a careful observer.[1403] Dogs well know
the difference between caressing and threatening gestures or tones; and
they seem to recognize a compassionate tone. But as far as I can make out,
after repeated trials, they do not understand any movement confined to the
features, excepting a smile or laugh; and this they appear, at least in
some cases, to recognize. This limited amount of knowledge has probably
been gained, both by monkeys and dogs, through their associating harsh or
kind treatment with our actions; and the knowledge certainly is not
instinctive. Children, no doubt, would soon learn the movements of
expression in their elders in the same manner as animals learn those of
man. Moreover, when a child cries or laughs, he knows in a general manner
what he is doing and what he feels; so that a very small exertion of
reason would tell him what crying or laughing meant in others. But the
question is, do our children acquire their knowledge of expression solely
by experience through the power of association and reason?

As most of the movements of expression must have been gradually acquired,
afterwards becoming instinctive, there seems to be some degree of a
priori probability that their recognition would likewise have become
instinctive. There is, at least, no greater difficulty in believing this
than in admitting that, when a female quadruped first bears young, she
knows the cry of distress of her offspring, or than in admitting that many
animals instinctively recognize and fear their enemies; and of both these
statements there can be no reasonable doubt. It is however extremely
difficult to prove that our children instinctively recognize any
expression. I attended to this point in my first-born infant, who could
not have learnt anything by associating with other children, and I was
convinced that he understood a smile and received pleasure from seeing
one, answering it by another, at much too early an age to have learnt
anything by experience. When this child was about four months old, I made
in his presence many odd noises and strange grimaces, and tried to look
savage; but the noises, if not too loud, as well as the grimaces, were all
taken as good jokes; and I attributed this at the time to their being
preceded or accompanied by smiles. When five months old, he seemed to
understand a compassionate, expression and tone of voice. When a few days
over six months old, his nurse pretended to cry, and I saw that his face
instantly assumed a melancholy expression, with the corners of the mouth
strongly depressed; now this child could rarely have seen any other child
crying, and never a grown-up person crying, and I should doubt whether at
so early an age he could have reasoned on the subject. Therefore it seems
to me that an innate feeling must have told him that the pretended crying
of his nurse expressed grief; and this through the instinct of sympathy
excited grief in him.

M. Lemoine argues that, if man possessed an innate knowledge of
expression, authors and artists would not have found it so difficult, as
is notoriously the case, to describe and depict the characteristic signs
of each particular state of mind. But this does not seem to me a valid
argument. We may actually behold the expression changing in an
unmistakable manner in a man or animal, and yet be quite unable, as I know
from experience, to analyse the nature of the change. In the two
photographs given by Duchenne of the same old man (Plate III. figs. 5 and
6), almost every one recognized that the one represented a true, and the
other a false smile; but I have found it very difficult to decide in what
the whole amount of difference consists. It has often struck me as a
curious fact that so many shades of expression are instantly recognized
without any conscious process of analysis on our part. No one, I believe,
can clearly describe a sullen or sly expression; yet many observers are
unanimous that these expressions can be recognized in the various races of
man. Almost everyone to whom I showed Duchenne’s photograph of the young
man with oblique eyebrows (Plate II. fig. 2) at once declared that it
expressed grief or some such feeling; yet probably not one of these
persons, or one out of a thousand persons, could beforehand have told
anything precise about the obliquity of the eyebrows with their inner ends
puckered, or about the rectangular furrows on the forehead. So it is with
many other expressions, of which I have had practical experience in the
trouble requisite in instructing others what points to observe. If, then,
great ignorance of details does not prevent our recognizing with certainty
and promptitude various expressions, I do not see how this ignorance can
be advanced as an argument that our knowledge, though vague and general,
is not innate.

I have endeavoured to show in considerable detail that all the chief
expressions exhibited by man are the same throughout the world. This fact
is interesting, as it affords a new argument in favour of the several
races being descended from a single parent-stock, which must have been
almost completely human in structure, and to a large extent in mind,
before the period at which the races diverged from each other. No doubt
similar structures, adapted for the same purpose, have often been
independently acquired through variation and natural selection by distinct
species; but this view will not explain close similarity between distinct
species in a multitude of unimportant details. Now if we bear in mind the
numerous points of structure having no relation to expression, in which
all the races of man closely agree, and then add to them the numerous
points, some of the highest importance and many of the most trifling
value, on which the movements of expression directly or indirectly depend,
it seems to me improbable in the highest degree that so much similarity,
or rather identity of structure, could have been acquired by independent
means. Yet this must have been the case if the races of man are descended
from several aboriginally distinct species. It is far more probable that
the many points of close similarity in the various races are due to
inheritance from a single parent-form, which had already assumed a human
character.

It is a curious, though perhaps an idle speculation, how early in the long
line of our progenitors the various expressive movements, now exhibited by
man, were successively acquired. The following remarks will at least serve
to recall some of the chief points discussed in this volume. We may
confidently believe that laughter, as a sign of pleasure or enjoyment, was
practised by our progenitors long before they deserved to be called human;
for very many kinds of monkeys, when pleased, utter a reiterated sound,
clearly analogous to our laughter, often accompanied by vibratory
movements of their jaws or lips, with the corners of the mouth drawn
backwards and upwards, by the wrinkling of the cheeks, and even by the
brightening of the eyes.

We may likewise infer that fear was expressed from an extremely remote
period, in almost the same manner as it now is by man; namely, by
trembling, the erection of the hair, cold perspiration, pallor, widely
opened eyes, the relaxation of most of the muscles, and by the whole body
cowering downwards or held motionless.

Suffering, if great, will from the first have caused screams or groans to
be uttered, the body to be contorted, and the teeth to be ground together.
But our progenitors will not have exhibited those highly expressive
movements of the features which accompany screaming and crying until their
circulatory and respiratory organs, and the muscles surrounding the eyes,
had acquired their present structure. The shedding of tears appears to
have originated through reflex action from the spasmodic contraction of
the eyelids, together perhaps with the eyeballs becoming gorged with blood
during the act of screaming. Therefore weeping probably came on rather
late in the line of our descent; and this conclusion agrees with the fact
that our nearest allies, the anthropomorphous apes, do not weep. But we
must here exercise some caution, for as certain monkeys, which are not
closely related to man, weep, this habit might have been developed long
ago in a sub-branch of the group from which man is derived. Our early
progenitors, when suffering from grief or anxiety, would not have made
their eyebrows oblique, or have drawn down the corners of their mouth,
until they had acquired the habit of endeavouring to restrain their
screams. The expression, therefore, of grief and anxiety is eminently
human.

Rage will have been expressed at a very early period by threatening or
frantic gestures, by the reddening of the skin, and by glaring eyes, but
not by frowning. For the habit of frowning seems to have been acquired
chiefly from the corrugators being the first muscles to contract round the
eyes, whenever during infancy pain, anger, or distress is felt, and there
consequently is a near approach to screaming; and partly from a frown
serving as a shade in difficult and intent vision. It seems probable that
this shading action would not have become habitual until man had assumed a
completely upright position, for monkeys do not frown when exposed to a
glaring light. Our early progenitors, when enraged, would probably have
exposed their teeth more freely than does man, even when giving full vent
to his rage, as with the insane. We may, also, feel almost certain that
they would have protruded their lips, when sulky or disappointed, in a
greater degree than is the case with our own children, or even with the
children of existing savage races.

Our early progenitors, when indignant or moderately angry, would not have
held their heads erect, opened their chests, squared their shoulders, and
clenched their fists, until they had acquired the ordinary carriage and
upright attitude of man, and had learnt to fight with their fists or
clubs. Until this period had arrived the antithetical gesture of shrugging
the shoulders, as a sign of impotence or of patience, would not have been
developed. From the same reason astonishment would not then have been
expressed by raising the arms with open hands and extended fingers. Nor,
judging from the actions of monkeys, would astonishment have been
exhibited by a widely opened mouth; but the eyes would have been opened
and the eyebrows arched. Disgust would have been shown at a very early
period by movements round the mouth, like those of vomiting,—that
is, if the view which I have suggested respecting the source of the
expression is correct, namely, that our progenitors had the power, and
used it, of voluntarily and quickly rejecting any food from their stomachs
which they disliked. But the more refined manner of showing contempt or
disdain, by lowering the eyelids, or turning away the eyes and face, as if
the despised person were not worth looking at, would not probably have
been acquired until a much later period.

Of all expressions, blushing seems to be the most strictly human; yet it
is common to all or nearly all the races of man, whether or not any change
of colour is visible in their skin. The relaxation of the small arteries
of the surface, on which blushing depends, seems to have primarily
resulted from earnest attention directed to the appearance of our own
persons, especially of our faces, aided by habit, inheritance, and the
ready flow of nerve-force along accustomed channels; and afterwards to
have been extended by the power of association to self-attention directed
to moral conduct. It can hardly be doubted that many animals are capable
of appreciating beautiful colours and even forms, as is shown by the pains
which the individuals of one sex take in displaying their beauty before
those of the opposite sex. But it does not seem possible that any animal,
until its mental powers had been developed to an equal or nearly equal
degree with those of man, would have closely considered and been sensitive
about its own personal appearance. Therefore we may conclude that blushing
originated at a very late period in the long line of our descent.

From the various facts just alluded to, and given in the course of this
volume, it follows that, if the structure of our organs of respiration and
circulation had differed in only a slight degree from the state in which
they now exist, most of our expressions would have been wonderfully
different. A very slight change in the course of the arteries and veins
which run to the head, would probably have prevented the blood from
accumulating in our eyeballs during violent expiration; for this occurs in
extremely few quadrupeds. In this case we should not have displayed some
of our most characteristic expressions. If man had breathed water by the
aid of external branchiae (though the idea is hardly conceivable), instead
of air through his mouth and nostrils, his features would not have
expressed his feelings much more efficiently than now do his hands or
limbs. Rage and disgust, however, would still have been shown by movements
about the lips and mouth, and the eyes would have become brighter or
duller according to the state of the circulation. If our ears had remained
movable, their movements would have been highly expressive, as is the case
with all the animals which fight with their teeth; and we may infer that
our early progenitors thus fought, as we still uncover the canine tooth on
one side when we sneer at or defy any one, and we uncover all our teeth
when furiously enraged.

The movements of expression in the face and body, whatever their origin
may have been, are in themselves of much importance for our welfare. They
serve as the first means of communication between the mother and her
infant; she smiles approval, and thus encourages her child on the right
path, or frowns disapproval. We readily perceive sympathy in others by
their expression; our sufferings are thus mitigated and our pleasures
increased; and mutual good feeling is thus strengthened. The movements of
expression give vividness and energy to our spoken words. They reveal the
thoughts and intentions of others more truly than do words, which may be
falsified. Whatever amount of truth the so-called science of physiognomy
may contain, appears to depend, as Haller long ago remarked,[1404]
on different persons bringing into frequent use different facial muscles,
according to their dispositions; the development of these muscles being
perhaps thus increased, and the lines or furrows on the face, due to their
habitual contraction, being thus rendered deeper and more conspicuous. The
free expression by outward signs of an emotion intensifies it. On the
other hand, the repression, as far as this is possible, of all outward
signs softens our emotions.[1405] He who gives way to violent gestures will
increase his rage; he who does not control the signs of fear will
experience fear in a greater degree; and he who remains passive when
overwhelmed with grief loses his best chance of recovering elasticity of
mind. These results follow partly from the intimate relation which exists
between almost all the emotions and their outward manifestations; and
partly from the direct influence of exertion on the heart, and
consequently on the brain. Even the simulation of an emotion tends to
arouse it in our minds. Shakespeare, who from his wonderful knowledge of
the human mind ought to be an excellent judge, says:—

Is it not monstrous that this player here,
But in a fiction, in a dream of passion,
Could force his soul so to his own conceit,
That, from her working, all his visage wann’d;
Tears in his eyes, distraction in ’s aspect,
A broken voice, and his whole function suiting
With forms to his conceit? And all for nothing!
Hamlet, act ii. sc. 2.

We have seen that the study of the theory of expression confirms to a
certain limited extent the conclusion that man is derived from some lower
animal form, and supports the belief of the specific or sub-specific unity
of the several races; but as far as my judgment serves, such confirmation
was hardly needed. We have also seen that expression in itself, or the
language of the emotions, as it has sometimes been called, is certainly of
importance for the welfare of mankind. To understand, as far as possible,
the source or origin of the various expressions which may be hourly seen
on the faces of the men around us, not to mention our domesticated
animals, ought to possess much interest for us. From these several causes,
we may conclude that the philosophy of our subject has well deserved the
attention which it has already received from several excellent observers,
and that it deserves still further attention, especially from any able
physiologist.