PART V

PSYCHICAL RUDIMENTS IN MAN

I

RUDIMENTARY ORGANS IN MAN

Reply to critics who deny the simian origin of man—Actual existence of rudimentary organs—Reductions in the structure of the organs of sense in man—Atrophy of Jacobson’s organ and of the Harderian gland in the human race

Several critics of _The Nature of Man_ have protested against my theory of the simian origin of man. Some of these found my arguments unsatisfactory and unconvincing. Others have attacked generally my suggestion that some anthropoid had been suddenly transformed to a primitive human being.

It is true that so long as we have little palæontological evidence as to the actual descent of man, we cannot discuss the subject without the aid of hypotheses. I think, however, that recent additions to knowledge confirm the theory of the descent of man in a way that ought to influence the most resolute opponents. I have in mind chiefly the arguments supplied by the embryology of anthropoid apes, and by the investigation of their blood. None the less, there are still many authors who maintain their opposition. One of my critics, Dr. Jousset,[150] enumerates certain differences in the structure of the skeleton in man and apes, and concludes that these radically separate man from apes.

No one has ever doubted that man was not identical in structure with the anthropoid apes, or that he differs from them in several characters of the skeleton and of many other organs. The differences, however, do not justify any radical separation of the two. The unusual length of arm, upon which my opponents throw so much weight, is in harmony with the mode of life of apes, as these climb on trees and walk on all four limbs. The difference between apes and Europeans in length of arm is certainly considerable, but is much less in the case of some lower races, such as the Veddahs. In the Akkas of Central Africa, the arms are so long that the hands nearly reach the knees. The fœtus of Europeans also shows an unusual length of arm, probably an ancestral feature. It is only after birth that the arms become relatively shorter.

All the other characters different in man and the apes, are equally secondary. On the other hand, just as apes differ amongst themselves, so also, the different races show differences often strongly marked. M. Michaelis,[151] in a comparative study of the muscular systems of monkeys, has made known many details of the musculature in the orang-outan and the chimpanzee, and it appears from his investigations that, although there are some differences between these two apes, they are both closely similar to man.

There are many variations in the muscular structure of man, and these find parallels in the muscles of apes. This is also the case with other abnormalities of structure, some of which resemble the condition in mammals much lower than apes. An example of this is the presence of additional pairs of nipples, arranged symmetrically on the sides of the chest and occasionally found in human beings. A similar abnormality has been found in some monkeys, and the best explanation of such an occurrence is that monkeys, like man, are descended from mammals which possessed several pairs of mammary glands.

The large number of abnormalities and rudimentary organs which may be found in man affords important evidence in favour of the descent of man from lower animals. Some authors, however, have tried to dispute this view and even deny the existence of rudimentary organs. M. Brettes,[152] amongst my opponents, has brought together most facts upon this matter, with the object of proving that such organs fulfil some function indispensable to the body and bear witness to the existence of a general plan of organisation. My opponent, however, confines himself to general propositions, laying much stress on a law of “the subordination of organs” without proving that rudimentary organs have an actual function. In _The Nature of Man_ I remarked on the uselessness of the wisdom teeth, which are not cut until long after childhood and which are useless in mastication. In many human beings these teeth never cut through the gum, and their absence is no disadvantage. This is a typical case of a rudimentary organ. To maintain the contrary it would be necessary to prove that the wisdom teeth fulfil an indispensable function and that their absence was in some way harmful to the organism. No one has been able to show this.

The mammary glands in males are another case of rudimentary organs. The function of these, of course, is well known in females, but it is only in the rarest cases that they are active in males.

The organs of sense supply many cases of rudimentary structures. Animals which live in caves, in the dark, do not discern objects by sight, and in these cases the eyes are rudimentary. It is quite impossible to deny the existence of rudimentary organs. They are extremely important guides to us in our investigation of the past history of the human race. The comparative study of the organs which are rudimentary in man and more or less well developed in lower animals is of fundamental importance in the problem of our origin.

The higher apes, or anthropoids, display reduction in some parts of the organs of sense. The organ of smell, for instance, is much less developed in them than in many other animals. Man has inherited the imperfect condition of this organ, and his sense of smell is much less developed than that of mammals which are lower in the scale of life. Man, however, because of his intelligence, has been able to tame domestic animals, such as dogs, ferrets, and pigs, and to make use of their acute sense of smell for tracking game or obtaining edible plants. The imperfect condition of the sense of smell in man in other cases is well replaced by his mental powers. He no longer recognises the approach of an enemy by the sense of smell, in order that he may take flight, because he has better means of defence than those of animals. It is not surprising, therefore, that the olfactory apparatus of man is much reduced as compared with that of lower mammals. In apes and man the nasal region of the head is much smaller than in their mammalian ancestors, and in the deep-lying parts of the system there are corresponding differences. Most mammals, for instance, and the dog in particular, have four turbinal bones, the purpose of which is to increase the surface of the mucous membrane of the nose, whilst in man there are only three, one of which is rudimentary.

The olfactory apparatus in most mammals contains a well-developed portion known as the organ of Jacobson, the probable function of which is to appreciate the flavour of food in the mouth. In man, this organ is in a rudimentary condition and cannot fulfil its function, as it is devoid of its proper nerve. This remnant, now useless, gives us information as to the evolution of the organ of smell in man. In the human fœtus, Jacobson’s organ is not only better developed than in adult man, but it is also provided with a stout nerve trunk, which disappears towards the end of embryonic life. The organ, however, cannot perform any olfactory function. The human fœtus, moreover, possesses five turbinals which later on become reduced to three, and of these only two develop completely.

The history of the evolution of the organ of smell, as it has been made out by comparative anatomy and embryology, links this apparatus in man with the corresponding organs of other mammals by means of these useless rudiments, which, however, are important evidence in scientific theory.

The auditory apparatus also has become reduced in man. Many animals, in the struggle for existence, require a very acute sense of hearing, more so than man or some of the most intelligent mammals. We have all seen how horses raise their ears to hear better when there is the slightest sound near them. Monkeys and man have lost this power, and man sometimes tries to supply the defect by artificial means. When a lecturer, for instance, is not speaking sufficiently loud some of the audience put their hands to their ears, making a kind of trumpet which serves to catch the sound. The human external ear is supplied with muscles, but in most cases these are too feeble to move it. In very rare cases persons can move their ears, the muscles inserted to the shell in most of us being mere rudiments of those that existed in our ancestors.

In the organ of sight, the little fold in the inner angle of the eye, known as the semilunar fold, is of special interest. This membrane is a useless vestige of a structure much better developed in lower mammals. In the dog it is present as a small third eyelid, supported by a special cartilage provided with a secreting gland, known as the Harderian gland. In birds, reptiles and frogs, the corresponding structures are much better developed. Everyone has seen the delicate membrane which, in the case of a bird, may shoot out from the inner angle of the eye and cover the whole of the exposed part of the eyeball (nictitating membrane). In these animals, the eye is protected by this third lid, which has its own muscles. As in the dog, this third eyelid of birds and lower vertebrates is generally provided with a large Harderian gland, which produces a liquid secretion like tears.

In most monkeys, this apparatus is much reduced. Many of them have still a small Harderian gland and a weak third eyelid. In man, as I have already said, there are only vestiges of these organs, the gland being almost atrophied and the third eyelid represented only by an insignificant crescentic fold. In the lower races the fold sometimes contains a small cartilage. Giacomini found it twelve times in sixteen negroes, whilst in 548 white people it was found only in three cases.

The interpretation of these facts is not doubtful. This little fold is the last vestige in use of an organ which was useful only in our remote ancestors.

The organs of reproduction in the human race also show a number of rudiments. There remain even traces of a hermaphrodite condition, a very low degree of organisation, going back to extremely remote ancestors. The evidence given by the very large number of abnormalities that are found in these organs makes it clear that, in the long period of the evolution of the human race, they have been subjected to a series of modifications. Thus, for instance, there is occasionally present in women a form of uterus resembling that of the lower mammals, or even the double uterus of marsupials.

The evolution of man has been dominated by the great development of the brain and of the intelligence, and man, accordingly, has lost many organs and functions which were of use in his more or less remote ancestors.

II

HUMAN TRAITS OF CHARACTER INHERITED FROM APES

The mental character of anthropoid apes—Their muscular strength—Their expression of fear—The awakening of latent instincts of man under the influence of fear

The facts of which I have given a résumé serve to show that evolution always leaves definite traces indicating its successive stages in the form of rudiments. It is probable, therefore, that the pre-human mental functions or psycho-physiological qualities, which have so long a history behind them, have also left more or less appreciable traces. These, however, must be more difficult to find than rudimentary organs which can be made visible by dissection.

If we turn first to the animals most nearly related to man, we find that the living anthropoid apes show in the clearest way their close relationship with the human race, and suggest that their kinship with our remoter ancestors must be even greater.

The anthropoid apes alive to-day are animals inhabiting chiefly virgin forests, and feeding on fruits and shoots, although they do not despise eggs or even little birds. To satisfy their wants, they climb with the greatest ease. Orang-outans and chimpanzees climb slowly and carefully, whilst gibbons show a greater agility and more perfect acrobatic power. They may be seen throwing themselves from branch to branch across spaces of forty feet with the greatest precision. They play at the top of very tall trees, hardly grasping the branches through which they pass, making leaps of from twelve to eighteen feet for hours together with little apparent exertion.

To give an idea of the dexterity and swiftness of gibbons, Martin took the case of a female which he observed in captivity. One time she hurled herself from a perch across a space at least twelve feet wide, against a window which one would have thought would have been immediately broken. To the great surprise of the spectators it was not broken. The gibbon seized with her hands the narrow board between the panes, and then in an instant twisted herself round and jumped back to the cage she had left, performing this manœuvre with great strength and the most marvellous precision.

The muscular force implied in the above narrative is possessed by all the anthropoid apes. Battel, an English sailor who gave the first description of the gorilla in the beginning of the 17th century, stated that the strength of that animal was so great that ten men could hardly master an adult specimen. The other anthropoids, although not so strong as the gorilla, nevertheless display surprising force.

Edouard, the young male chimpanzee which I used in my experiments on syphilis, struggled so much at the least touch that it took four men to master him. I had to give up allowing him to leave his cage because there was no way of getting him back to it. Even quite young chimpanzees, females not yet two years old, cannot be handled easily. Although they are very friendly, my specimens used to resist with all their strength when it was necessary to put them back in their cages for the night. Two men had much ado to shut them up.

Notwithstanding this great muscular force, the anthropoid apes are cowardly. They have no idea of their strength, but fly from the approach of the slightest imagined danger. My young chimpanzees, although their teeth and muscles were already formidable weapons, showed the greatest fear when I put with them animals even so weak and harmless as guinea-pigs, pigeons and rabbits. Mice frightened them very much at first, and it took them a considerable time before they got over their fear of so insignificant an enemy. When living in a state of nature the anthropoid apes scarcely ever assume the offensive. “Though possessed of immense strength,” wrote Huxley,[153] “it is rare for the Orang to attempt to defend itself, especially when attacked with fire-arms. On such occasions he endeavours to hide himself, or to escape along the topmost branches of the trees, breaking off and throwing down the boughs as he goes.” Savage[154] wrote of chimpanzees that “they do not appear ever to act on the offensive, and seldom, if ever really, on the defensive.” When a female was surprised on a tree with her young ones “her first impulse was to descend with great rapidity and make off into the thicket.”[155]

The gorilla, the strongest and most ferocious of the apes, has sometimes been observed to take the offensive. Savage, quoted by Huxley, said that “they are exceedingly ferocious, and always offensive in their habits, never running from man, as does the chimpanzee. The females and young, at the first cry, quickly disappear. He (the male) then approaches the enemy in great fury, pouring out his horrid cries in quick succession.”[156] Only males take the offensive, nor can this be of frequent occurrence, as one of the most recent observers, Koppenfels,[157] states that “the gorilla never attacks man spontaneously; he tries to avoid him, and, as a rule, takes to flight as soon as he sees a man, uttering peculiar guttural cries.”

Which of these characters are preserved in the human race? Man is naturally feebler and less of a gymnast than the great apes, but his disposition is cowardly. One of the earliest signs of mental activity in an infant is the fear of surrounding circumstances. The smallest change in its balance or its being put in a bath cause it to show signs of real terror. Later on, it is alarmed when it sees any kind of animal, exactly in the fashion of a young chimpanzee. The most harmless spider is enough to frighten it.

Although mental culture subdues fear to a large extent, fear reveals itself more or less strongly from time to time, and it is on such occasions that we may find in the human being psychological relics of his ancestors. An analysis of fear is of special interest.

The first result of the emotion of fear is flight. Consciousness of danger sets our limbs in motion, and our instinctive desire to escape displays itself even when flight is more dangerous than what we wish to avoid. At the first alarm of fire in a public building, people rush towards the exits and in so doing often perish from their wish to escape. Even in the extreme of terror, the desire of flight is one of the earliest impulses. Mosso, a well-known Italian physiologist, in a monograph on fear, relates that when a Calabrian brigand was sentenced to death “he uttered a sharp cry, heart-rending and terrible, looked around him as if he were eagerly seeking for something, and then stepped backwards as if to fly, and threw himself against the wall of the court, writhing, with arms outstretched, scratching at the wall as if he were trying to break through it.”

Although in such a case it was futile and often is harmful, the instinct of flight from danger is inherited from ancestors from a time when it served to save life. Attempts to escape are not the only signs of fear. There is often a trembling fit which would make flight impossible. In Mosso’s case of the Calabrian brigand, “after his struggles, cries and contortions, he fell on the ground in a motionless heap, like a wet rag; he became pale and trembled more than I have seen any other person tremble; his muscles seemed changed into a soft and quivering jelly.” This condition of trembling inertia is another legacy from animals. Quivering of the muscles often manifests itself in terrified animals. Darwin[158] wrote of it, “trembling is of no service, often of much disservice, and cannot at first have been acquired through the will, and then rendered habitual in association with any emotion.” The phenomenon seemed to him obscure and difficult to explain, a view shared by Mosso. The trembling of the musculature of the body is a generalised and exaggerated form of the movements of the cutaneous muscles in the condition known popularly as “goose-skin.” The latter, however, is a relic of an adaptation useful to some animals. The hedgehog rarely takes to flight at the approach of danger, but stands still, and using strongly developed muscles, rolls itself into a ball. In birds and many mammals, the muscles of the skin cause erection of the feathers or hairs. These movements often are performed during fright, and according to Darwin, serve not only to warm the skin, but sometimes to make the animal appear larger and more terrifying to enemies.

Fear and cold alike cause contraction of the superficial blood-vessels, and, in man, excite the contraction of the minute rudimentary muscles inserted to the roots of the hairs. “Goose-skin” is caused by the contraction of these muscles, the condition being a functional rudiment, no longer serving to warm the skin nor to make the body appear larger. In a few exceptional cases, “goose-skin” can be produced voluntarily. In the normal condition, the rudimentary cutaneous muscles of man are immobile, and it requires some special stimulation to set them in action.

Fear, which is occasionally able to excite the contraction of the involuntary muscles, also stimulates other muscles against the will. Under the influence of emotions that powerfully affect the nervous system, and particularly under that of fear, contractions of the bladder and intestines may be so violent that it is impossible to prevent the voiding of their contents. Accidents of this kind are not infrequent in the case of youthful candidates at examinations. Mosso relates of a friend, a volunteer in the war of 1866, that he was seized with terror during a battle and that the utmost efforts of his will failed to make his body endure the terrible spectacle.

The involuntary action of the bladder and intestines during fear is a legacy from animals. The phenomenon is common in dogs and monkeys. Chimpanzees, when laid hold of, discharge their urine and fæces. At Madeira I had an unusually cowardly _Cercopithecus_ monkey which when at all alarmed discharged the contents of the rectum. Quite possibly such a mechanism was useful for the preservation of the individual. The emission of various kinds of excretions is of use in the struggle for existence. In that way the fox drives the badger from its earth and takes possession of it, whilst polecats and skunks defend themselves against more powerful carnivorous animals by discharging on them fœtid secretions.

Instinctive fear is therefore a very powerful stimulant, awakening functions which are rudimentary and almost completely extinct. Sometimes it sets in operation mechanisms which have long been paralysed. Pausanias gives an example of a dumb young man who recovered his speech when he was terrified by seeing a lion. Herodotus relates that the son of Crœsus, who was dumb, on seeing a Persian about to kill his father, cried out: “You must not kill Crœsus,” and from that time onwards was able to talk. These ancient narratives have been confirmed by many modern observations. A woman, for instance, who had been dumb for several years, on seeing a fire, was terrified and cried out suddenly “Fire!” after which her speech was restored. Such are cases of the awakening of a function which has been arrested only for several years. But fear can bring into activity other mechanisms which have been inactive from time immemorial.

Many different kinds of animals can swim instinctively. This is true in the case of most birds and mammals. There are some species which show a repugnance to water, but none the less swim well enough if they are thrown into it. Cats shun water as much as possible, but, none the less, can swim quite easily. Historians relate that Hannibal had great difficulty in getting his elephants to cross the Rhone. Some females were ferried across first, upon which the other elephants threw themselves into the water to pursue them and swam across the river without any difficulty (Lenthéric, _Le Rhône_, 1892, p. 81).

The lower monkeys can swim without being taught, but the anthropoid apes have lost this power, and man also is without it. M. Volz[159] states that the different species of gibbons which live in Sumatra are separated by rivers. Their inability to swim makes these a complete barrier. It is probable that the lower races, in this respect, are better endowed than we are. It is said that in the case of negroes, children run to the sea or to rivers almost as soon as they leave the cradle, and learn to swim almost as quickly as to walk.[160] In the case of white people, many find it very difficult to learn to swim, and it is at least certain that swimming is not instinctive as in the case of our animal ancestors. Christmann,[161] the author of a treatise on swimming, states that the reason of man is a worse guide than the infallible instinct of the animal. Fear is able to stifle reason and to allow the instinct to come into play. It is known that children or adults may be taught to swim by throwing them into the water. Under the influence of fear, the instinctive mechanism inherited from animals awakens, and man soon becomes a swimmer. There are some teachers of swimming who use this method successfully. I have myself known an individual who learnt the art in that way, and M. Troubat, librarian at the International Library, has informed me that one of his friends, a journalist who died at Noyon several years ago, bathed in the Seine one evening at Neuilly when he could not swim. Unexpectedly finding himself beyond his depth, a sudden movement of fear saved him. Since then, he said, he knew how to swim.

Just as there are cases in which terror provokes flight, and others in which it causes an arrest of motion, so also fear may do a disservice to a swimmer. Those who employ fear as a means of teaching to swim, know that they must intervene if there is real danger. It is true, none the less, that up to a certain point fear can awaken functions which have been atrophied for numberless generations, and that we can learn from it something as to the evolution of the human race.

III

SOMNAMBULISM AND HYSTERIA AS MENTAL RELICS

Fear as the primary cause of hysteria—Natural somnambulism—Doubling of personality—Some examples of somnambulists—Analogy between somnambulism and the life of anthropoid apes—The psychology of crowds—Importance of the investigation of hysteria for the problem of the origin of man

The study of fear is interesting in other respects than those with which I have been dealing. It is also a primary cause of the obscure and complicated phenomena of hysteria.

Thus, for instance, amongst twenty-two hysterical women observed by Georget[162] the primary causes were: terror, 13 cases; extreme grief, 7 cases; extreme annoyance, one case. A patient of M. Pitres, of Bordeaux, first exhibited hysteria after being extremely terrified. A man with a tame bear had come to the village. The patient went to see the performance and elbowed her way through the crowd until she got to the front row. The bear, whilst dancing, passed so close that its cold muzzle touched the cheek of the young girl. Marie—for that was the patient’s name—was terrified. She ran quickly home, and almost on her arrival fell on her bed in an attack of convulsion and extreme delirium. Since then the attacks have been repeated many times, and the delirium associated with them always turns upon the terror caused by the bear touching her.

A hysterical woman at the Salpétrière is haunted by terrifying dreams. She thinks someone is trying to murder her, or to cut her throat, or that she is falling into water, and she keeps crying for help.[163]

Some of the most curious phases of hysteria are the paradoxical and extraordinary cases of so-called natural somnambulism, in which the patients, whilst asleep, perform all sorts of acts of which they remember nothing in their waking hours. Cases of duplication of personality are also known, in which the patients live in two different states without, in one of these, having the slightest remembrance of what takes place in the other. One of the most curious observations was that of the somnambulist who became _enceinte_ whilst in her second state. In her first, or normal condition, she was ignorant of the reason of her physical changes, although in the second state she knew about it quite well and spoke freely of it (Pitres, _op. cit._ II, 215).

In the state of natural somnambulism the patients generally reproduce the normal acts of their daily life which they have acquired the habit of performing unconsciously. Artisans devote themselves to their manual work, sempstresses begin to sew, maid servants brush shoes or clothes, lay the table and so forth. Educated persons devote themselves to intellectual work to which they are accustomed. Clergymen have been known to compose their sermons in the somnambulistic condition, and to read them over to correct mistakes in style or in spelling.

However, besides somnambulists who during slumber simply repeat the usual acts of their life, there are others who do special things to which they are unaccustomed.

It is these cases which are most interesting from my point of view. I shall take one case which has been specially well reported. A hysterical patient, a girl of 24 years of age, was admitted as an in-patient to the hospital Laënnec. One Sunday, she got up about one o’clock in the morning. The night watchman, who was alarmed, went for the night doctor, who witnessed the following scene. “The patient went to the staircase leading to the nurses’ quarters, then suddenly turned round and walked towards the wash-house. The door of that being closed, she then groped for a time and turned towards the women’s dormitory in which she had formerly slept. She went up to the top of the house where this dormitory was, and when she got on the landing, opened a window leading to the roof, went out of the window, walked along the gutter, under the horrified eyes of the nurse who followed her and who did not dare to speak to her, went in again by another window and went down the stairs.” “It was at this moment that I saw her,” said the night doctor; “she was walking noiselessly, her gait was automatic, her arms hanging by her sides, a little bent, the head erect and fixed, her hair disordered, her eyes wide open; she seemed like some strange apparition.”[164] This is obviously the case of a hysterical subject, who in a normal condition was not accustomed to climb upon roofs and walk along the gutters.

Another observation, reported by Charcot, related to a young man, seventeen years old, the son of a large manufacturer, and of good address. Tired out by working for his final examination, he had gone to bed early. Some time later he rose from the bed in his college dormitory, went out by a window, and without accident climbed on the roof and took a long and dangerous walk along the gutters. He was awakened before any accident occurred (Feinkind, p. 70).

A case observed by Dr. Mesnet and M. Mottet was still more interesting. A lady thirty years old and extremely hysterical got out of bed in the night, “dressed herself, completed her toilet without help, removed the furniture in her way without stumbling against it. She was indifferent and idle by day, but strenuous at night in performing the most varied acts. I have seen her walking about in her rooms, opening doors, going down to the garden, leaping on seats with the utmost agility, running about, in fact doing all these things much better than in her waking hours, in which she got about only slowly and with aid” (Feinkind, p. 84).

Horst has related an extraordinary incident which took place in the sixteenth century. “A soldier walked in his sleep to a window, and with the help of a rope climbed a high tower, secured a jackdaw’s nest with its young birds, and regained his bed, where he remained asleep until the morning.”[165] Unfortunately there are not sufficiently detailed facts regarding this incident, and for fully described cases we must return to modern times. Dr. Guinon has related one case in ample detail. A man thirty-four years of age, by occupation an interpreter, was taken into hospital for hysterical attacks. “One night soon after he came under the care of the physicians, this patient, towards one o’clock in the morning, suddenly arose from bed, threw open a window and jumped across the sill into the courtyard of the hospital. The attendants on duty ran after him, and saw him hurrying away, undressed and carrying a pillow in his arms. He traversed a series of gardens and walks, with the topography of which he was unacquainted, climbed a ladder and got on the roof of the hydrotherapeutic establishment, up and down which he proceeded to run with the greatest agility. Sometimes he stopped in his flight and rocked the pillow he was carrying, kissing and soothing it as if it were a child. Then he retraced the route he had taken.” On being questioned next morning, he had not the faintest remembrance of his nocturnal exploit. “A similar fit came on him five or six times” (Feinkind, p. 108).

The same patient, “after having turned over in bed several times, seized a pillow and held it to his breast. He then got out of bed, and, in his nightgown, ran through the dormitory to a door leading to the lavatories. He opened the door, readily but with violence, and entered one of the closets. Then, still holding the pillow against his chest with one arm, by a gymnastic feat both difficult and dangerous, yet which he performed with the utmost precision, using his feet and the free arm, he got hold of the edge of the frame of an open window, through which he swung himself to the sill, alighting on both feet, after which, preserving the pillow carefully from contact or shocks, he jumped to the ground (the infirmary ward was on the ground floor). He then ran quickly to the opposite corner of the courtyard, passing the whole length of the great building at full speed, holding the pillow carefully. By a path which led round the building, he reached a corner where there was a tower supporting a great water-tank. A kind of metallic ladder, placed almost vertically and with rounded steps, led up the side of the tower to a sort of observation-landing which at one point was adjacent to the edge of the roof of the bath-house.

“The patient set himself to climb this ladder without any hesitation, holding on by his free hand and placing his naked feet on the rounded steps with extreme precision. When he reached the nearest point to the roof of the bath-house he leapt upon that, and at a running pace climbed the zinc roof to the crest, looking round him from time to time to see if his imaginary pursuers were near. He ran along the crest which was so narrow that his feet had to be placed alternately on either side on the slopes of the steep-pitched roof, a performance so dangerous that none of the officials would follow him, and which none the less he performed with complete assurance and without a single slip.

“When he reached the middle of the building he sat down on the crest of the roof, leaning against a ventilating chimney. He then took the pillow which he had been carrying carefully, placed it on his knees with a corner against his shoulder, and began to rock it as if it were a child, crooning to it, stroking it with his hand or with his cheek that he pressed gently against the corner. From time to time his eyebrows contracted and his looks hardened, and he gazed around him as if he were being pursued or watched, then gave a growl of rage, and took to flight again, carrying the pillow on his dangerous path. All the time he kept speaking, but we could not hear what he said. He saw nothing that was not in his dream; he did not understand when his name was called aloud; but he could hear, for at the slightest sound near him he rushed off again as if his pursuers were upon him. This episode lasted about two hours, during which he had climbed over all the roofs in the vicinity, defying our pursuit of him” (Feinkind, pp. 106-112).

I could give other similar cases, but I think that I have shown sufficiently that man, when in the condition of natural somnambulism, exhibits qualities that he does not possess in the normal state, becoming strong, adroit, and a good gymnast, like his anthropoid ancestors. The close resemblance between the manœuvres of Martin’s gibbon, which I described earlier in this chapter, and the dangerous exploits of some sleep walkers is most striking.

The impulses to climb on roofs and poles, to run along in rain gutters, to climb a tower to take a bird’s nest, are characteristic examples of the instinctive actions of climbing animals, like the anthropoid apes. Dr. Barth[166] defines somnambulism as “a dream with exaltation of the memory and automatic action of the nervous centres, without voluntary and conscious control.” “The striking exaltation of the memory is the dominating condition. The extreme exactness of the memory of places displayed by the somnambulist makes us understand how he performs his nocturnal wanderings, doing almost without the aid of his senses numberless deeds of which he would be practically incapable in a waking condition.” However, as such a patient performs new acts which he has never accomplished before in his own individual life, we must suppose that the exaltation of memory includes extremely ancient facts, dating perhaps from the pre-human period. Man has inherited from his ancestors a number of mechanisms of the brain, the activity of which is inhibited by restraints which have been developed later. Just as man possesses mammary glands which under ordinary conditions cannot secrete milk, so also, in his brain, there are contained groups of cells which are inactive in the normal condition, but, also, just as in some exceptional cases man and the males of several species of mammals are able to give milk, so also in abnormal conditions the atrophied mechanisms of other nervous centres begin to act.

The secretion of milk by males is a return to an extremely ancient condition in which both sexes were able to nourish the young; so, also, the gymnastic feats and the extraordinary strength of somnambulists are a return to a normal condition much less remote from us than lactation in males.

It is curious to find that, in some cases, natural somnambulism is associated with power to move the shell of the ear. I know two brothers, who, when they were young, used to walk in their sleep in the most typical way. One of them, a chemist, used to climb on a high cupboard, or simply walk about in the room. The other brother, a sailor, in a fit of somnambulism, climbed to the top mast of a sailing ship. These brothers, who were somnambulists, had the cutaneous muscles extremely well developed and were able to move their ears voluntarily.

In this case the abnormality was hereditary in the family, and the two daughters of one of the brothers were also somnambulistic and had control over the muscles of the ears. Here, then, is a case of the simultaneous recurrence of two characters of our ancestors: mobility of the ear and agility in gymnastic feats. M. Barth characterises the somnambulist as “a living automaton in whom conscious will is for the time being destroyed.” According to him, the somnambulist “acts at the suggestion of circumstances, and what seem most extraordinary in what he does are in reality instinctive reactions.” This description agrees well with my view that in natural somnambulism the instincts of our pre-human ancestors are awakened, instincts which under normal conditions are latent and rudimentary.

Sometimes, under the stimulus of fear, the instinctive mechanism of swimming is awakened in man. It would be extremely interesting to know if a similar occurrence took place in somnambulists. I have been unable to find in literature any sufficient facts upon this subject. I can quote only one case, and that with all reserve, which was published in the article “Somnambulism” in the _Dictionnaire des Sciences Médicales_. “It is related that a somnambulist who took to swimming during one of his fits was called by his name several times, and became so frightened when he awoke that he was drowned.” It would be extremely interesting to collect more numerous facts on the instincts shown by somnambulists.

I have given a good deal of attention to natural somnambulism with the idea that I should find in it traits recalling those of the life of anthropoid apes. I think that the extremely varied phenomena of hysteria could supply us with other facts, useful in investigating the psycho-physiological history of man. Perhaps some of the facts of so-called “lucidity” which are well established could be explained as the awakening of special sensations atrophied in the human race, but present in animals. It is known that in vertebrate anatomy organs are found which have the structures of organs of sense, but which are absent or quite rudimentary in the human body. On the other hand, it is known that animals perceive some phenomena of the surrounding world, for the perception of which man has no organs of sense. Fish, for instance, appreciate gradations in the depth of water, birds and mammals have a sense of orientation and can anticipate changes in the weather more exactly than our meteorological science. When under the influence of hysteria, man may possibly be able to recover these senses of our remote ancestors, and to know things of which he is ignorant in the normal condition.

Hysteria is common to man and animals. Amongst the numerous chimpanzees which I have owned, several have shown signs of hysteria. Some, when they were in the slightest degree annoyed, lay on the ground, screaming terribly, and rolling about like children in a fit of passion. One young chimpanzee used to pull out its hair when it was in a fit of temper. The view that hysteria is a relapse to the condition of our animal ancestors is supported by the conception of hysterical phenomena, suggested by Dr. Babinsky.[167] This well-known neurologist thinks that “the phenomena of hysteria have two special characters, the one being that they can be reproduced by suggestion in some cases with the most complete fidelity, and the other that they can disappear under the sole influence of persuasion.” M. Babinsky thinks that “the hysteric patient is neither unconscious nor completely conscious, but is in a state of special consciousness.” In my opinion the latter condition corresponds to the state of mind of our more or less remote ancestors.

Occasionally a man, under some sudden impulse, falls into a condition of extreme violence, and, being unable to control himself, commits acts of which he repents immediately afterwards. It is the custom to say that at such times the brute has awakened in the man. This is more than a metaphor. (Probably some nervous mechanism from a remote ancestor has come into action, at the call of some stimulation.) As our anthropoid ancestors and primitive man lived in tribes, it is natural that when men are grouped together, certain savage instincts should awaken. In this connection it is interesting to study the psychology of crowds. When man is surrounded by a great many of his fellows, he becomes particularly responsive to suggestion. This condition is characterised as follows by M. G. Le Bon,[168] the author of a study on the psychology of crowds: “The most careful observations seem to prove that an individual immerged for some length of time in a crowd in action soon finds himself—either in consequence of the magnetic influence given out by the crowd, or from some other cause of which we are ignorant—in a special state, which much resembles the state of fascination in which the hypnotised individual finds himself in the hands of the hypnotiser. The activity of the brain being paralysed in the case of the hypnotised subject, the latter becomes the slave of all the unconscious activities of his spinal cord, which the hypnotiser directs at will. The conscious personality has entirely vanished; will and discernment are lost. All feelings and thoughts are bent in the direction determined by the hypnotiser” (p. 11). Man, under the influence of the crowd, gets into a condition like that of a hysterical patient and displays a state of mind identical with that of our ancestors. “Moreover, by the mere fact that he forms part of an organised crowd, a man descends several rungs in the ladder of civilisation. Isolated, he may be a cultivated individual; in a crowd, he is a barbarian—that is, a creature acting by instinct” (p. 13).

It is quite natural to find relics of our prehistoric past in all kinds of hysterical phenomena. We could reach extremely interesting facts regarding the tribal and sexual life of apes, if we tried to compare with them the phenomena of human hysteria. The passionate gestures which are characteristic of some hysterical cases could probably be explained in this way quite simply, and the wild cries uttered by patients in acute hysteria would be similarly explicable.

I think that just as anatomists seek for points of comparison between man and animals, as palæontologists make excavations to discover the buried remains of creatures intermediate between man and apes, so also, psychologists and doctors should investigate the rudimentary psycho-physical functions with the object of building up the history of the evolution of our psychical life. It cannot be doubted that in this branch of science new arguments would be found to support the already well founded theory of the simian origin of the human race.