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 bathhouse 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 manoeuvres 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. Barth1 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.

1 Du Sommeil non naturel, Paris, 1886.

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 psychophysiological 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. 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,2 the author of a study on the 1 Conférence faite à la Société de l'Internat, June 28th, 1906.

2 The Crowd: a Study of the Popular Mind. English translation, London, 1896.

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