“THE Expression of the Emotions in Man and Animals” followed “The Descent of Man” in 1872. The motive which suggested it was the desire to explain the complexities of expression on evolution principles. But the study of emotional expression had evidently engaged Darwin’s attention at least from the time when the Fuegians and the Gauchos had vividly roused his imaginative faculties; and his direct observations commenced as early as 1838; when he was already inclined to believe in evolution, and were continued at intervals ever after. The third edition of Sir Charles Bell’s “Anatomy of Expression,” published in 1844, while greatly admired by him, was unsatisfactory in being throughout based on the conviction that species came into existence in their present condition; and notwithstanding that Bain and Herbert Spencer had made considerable advances in a treatment of the subject based on physiology, an exhaustive book was wanted, which should throw on Expression the new and interesting light of Darwinism.

What was Darwin’s method? Observation, cleverly devised appeal to nature; observation over a wide field as to the varied races of man still existing, utilising the aid of travellers and residents in many lands; observation of domestic animals in familiar and in untried circumstances; observation of infants, especially his own, from a very early age; observation of the insane, who are liable to the strongest passions, and give them uncontrolled vent. It was in 1867 that Darwin circulated his group of questions designed to ascertain the mode of expressing every emotion, and their physical concomitants in every possible race. Sculpture, paintings, and engravings, afforded little evidence, because beauty is their main object, and “strongly contracted facial muscles destroy beauty.” Information was specially sought as to natives who had had little communication with Europeans, and in whom imitation might not have destroyed ancestral and original expression.

The result was to develop three principles which appeared, in combination, to account for most of the expressions and gestures involuntarily used by man and animals. The first was that of serviceable associated habits: certain complex actions being somehow serviceable in particular states of mind, to gratify and relieve certain sensations, desires, &c., whenever the same state of feeling is repeated, there is a tendency to the same movements or actions, though they may not then be of the least use. The second principle, that of antithesis, is the converse of the last; when an opposite state of mind is induced, there is an involuntary tendency to directly opposite movements, though of no use. The third principle, that of the direct action of the nervous system, is independent of the will and of habit; nerve force being generated in excess by strong emotions.

In discussing all these principles we discover how every thought and every circumstance of the great naturalist seem to have been utilised in his life work. “I have noticed that persons in describing a horrid sight, often shut their eyes momentarily and firmly, or shake their heads as if not to see, or to drive away, something disagreeable; and I have caught myself, when thinking in the dark of a horrid spectacle, closing my eyes firmly.” “I noticed a young lady earnestly trying to recollect a painter’s name, and she first looked to one corner of the ceiling, and then to the opposite corner, arching the one eyebrow on that side, although of course there was nothing to be seen there.” “Many years ago I laid a small wager with a dozen young men that they would not sneeze if they took snuff, although they all declared that they invariably did so; accordingly they all took a pinch, but from wishing much to succeed, not one sneezed, though their eyes watered, and all, without exception, had to pay me the wager.” “I put my face close to the thick glass-plate in front of a puff-adder in the Zoological Gardens, with the firm determination of not starting back if the snake struck at me; but as soon as the blow was struck, my resolution went for nothing, and I jumped a yard or two backwards with astonishing rapidity. My will and reason were powerless against the imagination of a danger which had never been experienced.” “I observed that though my infants started at sudden sounds, when under a fortnight old, they certainly did not always wink their eyes, and I believe never did so. The start of an older infant apparently represents a vague catching hold of something to prevent falling. I shook a pasteboard box close before the eyes of one of my infants, when 114 days old, and it did not in the least wink; but when I put a few comfits into the box, holding it in the same position as before, and rattled them, the child blinked its eyes violently every time, and started a little.” The behaviour of dogs and horses under many circumstances was watched. Cats and monkeys were most carefully scrutinised. At all moments Darwin seized upon and recorded the passing emotion and its associated movements. “I remember once seeing a boy who had just shot his first snipe on the wing, and his hands trembled to such a degree from delight, that he could not for some time reload his gun;” an instance of an emotional movement being disadvantageous.

Some of Darwin’s descriptions of emotional outbursts are among the best portions of his writing; as when he speaks of a mother whose infant has been intentionally injured, “how she starts up with threatening aspect, how her eyes sparkle and her face reddens, how her bosom heaves, nostrils dilate, and heart beats.” In describing a mourner when quiescent, he says: “The sufferer sits motionless, or gently rocks to and fro; the circulation becomes languid; respiration is almost forgotten, and deep sighs are drawn. All this reacts on the brain, and prostration soon follows with collapsed muscles and dulled eyes.”

One of the most striking features of this book is the evidence it affords of Darwin’s acuteness and persistence in observation during his travels, and of the excellence of his memory. “I remember that my mules and dogs, brought from a lower and warmer country, after spending a night on the bleak Cordillera, had the hair all over their bodies as erect as under the greatest terror.” He noted that Jemmy Button, the Fuegian, blushed when he was quizzed about the care which he took in polishing his shoes, and in otherwise adorning himself; and this fact long after is fitted into the theory of blushing. Guanacoes in South America, when not intending to bite, but merely to spit their offensive saliva from a distance at an intruder, yet retract their ears as a sign of their anger; and Darwin found the hides of several which he shot in Patagonia, deeply scored by teeth marks, in consequence of their battles with each other. A party of natives in Tierra del Fuego endeavoured to explain that their friend, the captain of a sealing vessel, was out of spirits, by pulling down their cheeks with both hands, so as to make their faces as long as possible; and the fact is treasured till it comes in to illustrate the lengthening of features under depression. As if he foreknew that he should want the fact forty years later, he inquired of Jemmy Button whether kissing was practised by his people, and learnt that it was unknown to them. “I remember,” he says, “being struck whilst travelling in parts of South America, which were dangerous from the presence of Indians, how incessantly—yet as it appeared, unconsciously—the half-wild Gauchos closely scanned the whole horizon.” “In Tierra del Fuego, a native touched with his finger some cold preserved meat which I was eating at our bivouac, and plainly showed utter disgust at its softness; whilst I felt utter disgust at my food being touched by a naked savage, though his hands did not appear dirty.” And this illustrates the primary meaning of disgust—anything offensive to the taste.

In later years his own children, and his domestic pets, were incessantly watched, and suitable experiments were devised to bring out the real nature of their expressions. The period at which tears are formed and crying begins, the shape of the mouth in crying, the contraction of the muscles in shouting, the effects of steady gazing at objects, the various stages of smiling, the effects of shyness, shame, and fear, are all set before us, as thus observed. For instance, “I asked one of my boys to shout as loudly as he possibly could, and as soon as he began he firmly contracted his orbicular muscles (surrounding the eyes). I observed this repeatedly, and on asking him why he had every time so firmly closed his eyes, I found that he was quite unaware of the fact: he had acted instinctively or unconsciously.” Some of his early observations were afterwards published by Darwin in Mind, vol. ii., under the title of “A Biographical Sketch of an Infant.”

Here is a carefully-worded and very suggestive experiment on animals: “Many years ago, in the Zoological Gardens, I placed a looking-glass on the floor before two young orangs, who, as far as it was known, had never before seen one. At first they gazed at their own images with the most steady surprise, and often changed their point of view. They then approached close, and protruded their lips towards the image, as if to kiss it, in exactly the same manner as they had previously done towards each other when first placed, a few days before, in the same room. They next made all sorts of grimaces, and put themselves in various attitudes before the mirror; they pressed and rubbed the surface; they placed their hands at different distances behind it; looked behind it; and finally seemed almost frightened, started a little, became cross, and refused to look any longer.” So monkeys were tested with a dressed doll, a live turtle, and stuffed snakes, &c.

The mode and purpose of erection of the hair, feathers, and dermal appendages of animals were the subject of much careful inquiry. Chimpanzees, monkeys, baboons, and many other creatures, were tested in the Zoological Gardens. A stuffed snake taken into the monkey-house caused several species to bristle. When Darwin showed the same to a peccary, the hair rose in a wonderful manner along its back. A cassowary erected its feathers at sight of an ant-eater.

Every unexpected occurrence was pressed into service. Witness the following anecdote: “One day my horse was much frightened at a drilling machine, covered by a tarpaulin and lying on an open field. He raised his head so high that his neck became almost perpendicular; and this he did from habit, for the machine lay on a slope below, and could not have been seen with more distinctness through the raising of the head; nor if any sound had proceeded from it could the sound have been more distinctly heard. His eyes and ears were directed intently forwards; and I could feel through the saddle the palpitations of his heart. With red, dilated nostrils, he snorted violently, and whirling round, would have dashed off at full speed had I not prevented him.”

We see, too, in this book the results of Darwin’s extensive reading. The novelists are laid considerably under contribution, their power of describing expressive signs of emotion being particularly appreciated. Dickens, Walter Scott, Mrs. Oliphant, and Mrs. Gaskell are among the novelists quoted; while the author of Job, Homer, Virgil, Seneca, Shakespeare, Lessing, Sir Joshua Reynolds, and many other deceased writers, illustrate the subject. The living authorities—scientific men, travellers, doctors—referred to for facts are exceedingly numerous, including Sir James Paget, Professor Huxley, Mr. Herbert Spencer, Sir J. Crichton Browne, Sir Samuel Baker, Sir Joseph Lister, Professors Cope and Asa Gray, and many others.

One of the most interesting chapters in the book is that dealing with blushing. It is shown to depend on self-attention, excited almost exclusively by the opinion of others. “Every one feels blame more acutely than praise. Now, whenever we know, or suppose, that others are depreciating our personal appearance, our attention is strongly drawn towards ourselves, more especially to our faces.” This excites the nerve centres receiving sensory nerve for the face, and in turn relaxes the blood capillaries, and fills them with blood. “We can understand why the young are much more affected than the old, and women more than men, and why the opposite sexes especially excite each others’ blushes. It becomes obvious why personal remarks should be particularly liable to cause blushing, and why the most powerful of all the causes is shyness; for shyness relates to the presence and opinion of others, and the shy are always more or less self-conscious.”

One great result made clear by Darwin is that the muscles of expression have not been created or developed for the sake of expression only, and that every true or inherited movement of expression had some natural or independent origin. All the chief expressions are proved to be essentially the same throughout the world, which is an additional argument for man being descended from one stock. We cannot refrain from admiring the tone of the pages which close the book, describing as they do the probable expressions of our early ancestors, their utility, the value of differences of physiognomy, and the desirability or otherwise of repressing signs of emotion. The subject, says the author, “deserves still further attention, especially from any able physiologist;” and so simply ends a volume of surpassing human interest, a text-book for novelists and students of human nature, a landmark in man’s progress in obedience to the behest “Know thyself.”

To fully measure the merit of one so far elevated above ordinary men is almost impossible; rather is it desirable to recognise the undeniable greatness of a great man, and learn all that is possible from him. An undoubted authority in mental science, however, has given a judgment on Darwin’s services to that science, which it is right to quote: “To ourselves it almost seems one of the most wonderful of the many wonderful aspects of Mr. Darwin’s varied work that by the sheer force of some exalted kind of common-sense, unassisted by any special acquaintance with psychological method, he should have been able to strike, as it were, straight down upon some of the most important truths which have ever been brought to light in the region of mental science.”12 These truths are specified as the influence of natural selection in the formation of instinct, in the “Origin of Species;” the evolution of mind and of morals, in the “Descent of Man,” considered by the late Professor Clifford as containing the simplest and clearest and most profound philosophy that was ever written on the subject; and the evolution of expression in the book described in this chapter. Thus, says Mr. Romanes, in respect both of instincts and intelligence, the science of comparative psychology may be said to owe its foundation to Darwin.