result of medical knowledge of this disease is that it is impossible to doubt that the sleepiness is due to intoxication produced by the poison of the trypanosome.

: Claparède has opposed what he calls an "instinctive" theory to the toxic theory of sleep. According to this theory, sleep is the manifestation of an instinct "the object of which is to arrest activity; we do not sleep because we are intoxicated or exhausted, but to prevent ourselves from falling into such a condition." However, in order to bring this narcotic instinct into play, certain conditions are necessary, one of which certainly would be the intoxication of the nerve centres. M. Claparède supposes that sleep is an active phenomenon, induced when waste matter begins to accumulate in the organism. "To bring about sleep, the nerve centres must be influenced by waste matter, and this influence can readily be regarded as a kind of intoxication."

Hunger is an instinctive sensation as much as sleepiness, but it does not appear until our tissues are in a condition of exhaustion, the exact nature of which cannot as yet be indicated. There is no real contradiction between the toxic and instinctive theories of sleep. The two theories represent different sides of a special condition of the organism.

The analogy between sleep and natural death is in favour of the supposition that the latter, also, is due to an intoxication much more profound and serious than that which results in sleep. Therefore, as natural death in human beings has been studied only very superficially, it is impossible to do more than frame theories regarding it.

It would be natural if, just as in sleep there is an instinctive desire for rest, so also the natural death of man were preceded by an instinctive wish for it. As I have already discussed this subject in the "Nature of Man" (chap. xi)

I need not deal with it at length here. I should like, however, to add some information which I have recently obtained.

The most striking fact in favour of the existence of the instinct for natural death in man appears to me to have been related by Tokarsky in regard to an old woman. While Tokarsky was alive I asked one of his friends to obtain for me further details of this very interesting case. Unfortunately Tokarsky could add nothing to what he had already published in his article. I think that I have discovered the source of his information. In his famous book on the Physiology of Taste1 Brillat-Savarin relates as follows:-"A great-aunt of mine died at the age of 93. Although she had been confined to bed for some time her faculties were still well preserved, and the only evidence of her condition was the decrease in appetite and weakening of her voice. She had always been very friendly to me, and once when I was at her bedside, ready to tend her affectionately, although that did not hinder me from seeing her with the philosophical eye that I always turned on everything about me, 'Is it you, my nephew?' she said in her feeble voice. Yes, Aunt, I am here at your service, and I think you will do very well to take a drop of this good old wine.' 'Give it me, my dear; I can always take a little wine.' I made ready at once, and gently supporting her, gave her half a glass of my best wine. She brightened up at once, and turning on me her eyes which used to be so beautiful, said: 'Thank you very much for this last kindness; if you ever reach my age you will find that one wants to die just as one wants to sleep.' These were her last words, and in half an hour she fell into her last sleep." The details make it certain that this was 1 Paris, 1834, 4th edition, vol. ii, p. 118.

a case of the instinct of natural death. The instinct showed itself at an age not very great in the case of a woman who had preserved her mental faculties. Generally, however, it seems not to appear till much later, for old men usually exhibit a keen wish to live.

It is a well-known saying that the longer a man has lived the more he wishes to live. Charles Renouvier,1 a French philosopher who died a few years ago, has left a definite proof of the truth of the saying. When he was eightyeight years old, and knew that he was dying, he recorded his impressions in his last days. Let me quote from what he wrote four days before his death. "I have no illusions about my condition; I know quite well that I am going to die, perhaps in a week, perhaps in a fortnight. And I have still so much to say on my subject." "At my age I have no longer the right to hope: my days are numbered, and perhaps my hours. I must resign myself." "I do not die without regrets. I regret that I cannot foresee in any way the fate of my views." "And I am leaving the world before I have said my last word. A man always dies before he has finished his work, and that is the saddest of the sorrows of life." "But that is not the whole trouble, when a man is old, very old, and accustomed to life, it is very difficult to die. I think that young men accept the idea of dying more easily, perhaps more willingly than old men. When one is more than eighty years old, one is cowardly and shrinks from death. And when one knows and can no longer doubt that death is coming near, deep bitterness falls on the soul." "I have faced the question from all sides in the last few days; I turn the one idea over in my mind; I know that I am going to die, but I cannot persuade myself that I am going to die. It is not the

1 Revue de métaphysique et de morale, March, 1904.

The philosopher does not The old man has not the

philosopher in me that protests. fear death; it is the old man. courage to submit, and yet I have to submit to the inevitable."

I know a lady, a hundred and two years old, who is so oppressed by the idea of death, that those about her have to conceal from her the death of any of her acquaintances. Mde. Robineau, however, when between one hundred and four and one hundred and five years old, became quite indifferent to the close approach of her own death. She often expressed a wish for it, thinking herself useless in the world.

M. Yves Delage1 in an analysis of my "Nature of Man" doubted the existence of an instinct for death. "Animals," said he, "cannot have the instinct for death, because they do not know of death. In their case, we must consider that what happens is an apathy tending to the abolition of the sense of self-preservation. In man, the knowledge of death implies that the indifference to its approach cannot be an instinct." "There may be developed, at the end of life, a special state of mind which accepts death with indifference or with pleasure, but such a state cannot be designated as an instinct." M. Delage, however, does not suggest what the state of mind in question is to be called. As the aunt of Brillat-Savarin compared her sensations just before death with the desire to sleep, and as this desire is an instinctive manifestation, I think that the cheerful acquiescence in death, exhibited by extremely old people, is also a kind of instinct. However, the important matter is that the sentiment exists, and not what we are to call it. M. Delage is far from denying its existence.

1 Année biologique, vol. vii, p. 595.

Dr. Cancalon,1 another of my critics, cannot admit the existence of an instinct of death, "because of the theory of evolution. Of what good would it have been, as M. Metchnikoff tells us that natural death is very rare; how could it have been transmitted, as it comes into existence long after the age of reproduction, and how could it have aided the survival of the species? If its existence were proved as the result of biological evolution, it would be a contradiction of adaptation and an argument in favour of final causes." I cannot agree in any way with these opinions. In the first place, it is well known that men and animals have many harmful instincts that do not tend to the survival of the species. I need recall only the disharmonic instincts which I described in the "Nature of Man," such as the anomalies of the sexual instinct, the instinct which drives parents to devour their young or which attracts insects to flames. The instinct of natural death is far from being harmful, and may even have many advantages. If men were convinced that the end of life were natural death accompanied by a special instinct like that of the need for sleep, one of the greatest sources of pessimism would disappear. Now pessimism is the cause of the voluntary death of a certain number of people and of many others refraining from reproduction. The instinct of natural death would contribute to the maintenance of the life of the individual and of the species. On the other hand, there is no difficulty in admitting the existence of instincts hostile to the preservation of the species, especially in the case of man, in whom individualism has reached its highest development. As man is the only animal with a definite notion of death, there is nothing. extraordinary if it is in man that the instinctive wish for

1 Revue occidentale, July 1st, 1904, vol. xxx, p. 87.

K