fact, but, absorbed in scientific study, he kept himself apart from the indulgences of youth and lived a sober life. In this way he found that his strength and activity were fully preserved at a time of life when his older brother was already a physical wreck. I have quoted this example, not to repeat the banal idea that a sober life is followed by a healthier old age than an intemperate life, but because I wish to insist on the importance of the development of the instinct of life in the course of each individual life. I see that this idea is very little known. I was present at the last moments of my older brother (he was called Ivan Ilyitch, and he was the subject of the famous story of Tolstoi: _The Death of Ivan Ilyitch_). Knowing that he was going to die from pyemia, at the age of forty-five, my brother preserved his great intelligence in all its clearness. As I sat by his bedside he told me his reflections in the most objective fashion possible. The idea of his death was for long very terrible to him, but “as we all die” he came to “resign himself, saying that after all there was only a quantitative difference between death at the age of forty-five and later on.” This reflection, which relieved the moral sufferings of my brother, is none the less untrue. The sense of life is very different at different ages, and a man who lives beyond the age of forty-five experiences many sensations which he did not know before. There is a great evolution of the mind during the advance of age. Even if we do not accept the existence of an instinct of natural death as the crown of normal life, we cannot deny that youth is only a preparatory stage and that the mind does not acquire its final development until later on. This conception should be the fundamental principle of the science of life and the guide for education and practical philosophy. Individual morality consists of conduct permitting the accomplishment of the normal cycle of life and ending in a feeling of satisfaction as complete as possible and which can be reached only in advanced age. And so, when we see a man wasting his health and strength and youth, and thus making himself incapable of feeling the most complete pleasure in life, we call him immoral. A man entirely isolated does not exist in nature. We are born weak and incapable of satisfying our needs and at once come into relations with the human being who feeds us and protects us. The child, although egoistic, becomes attached to his protector, and in this way the feeling of sympathy is born. Guided by this feeling as well as by the sense of his own interest, the child soon begins to employ his will in restraining some of his instincts, which, none the less, are quite natural. Thus, the fear of being deprived of food makes him obedient to his protectors. The child cannot complete his normal cycle without pursuing a certain moral conduct.