_P.S._--Let those who think that, according to my principles, I should have lived a hundred years, "forgive" me my premature end in view of the extenuating circumstances above-mentioned (intense and precocious activity, excitable temperament, nervous disposition, and late beginning of the rational diet). E. M. [29] 28th _June_ 1914.--I have again analysed my urine and I again find indican in fairly large quantities in spite of a diet which is as rational as possible. I am trying to elucidate this strange contradiction. The very next day he felt well enough to return to his work. When urged to settle down in Paris in order to avoid the fatigue of the journey, he replied that the peace and pure air of Sèvres were indispensable to his health, that the journey did not fatigue him in the least, but on the contrary provided him with wholesome exercise and a pleasant walk. Knowing how prudent he was, I did not dare to insist for fear of mistaking what was really best for him. And life gradually resumed its normal course.... For a long time Metchnikoff had been observing himself very attentively; he took regular notes on the influence of the food diet which he followed; by the analysis of his urine, he sought for indications respecting the toxic products of his intestinal flora; he studied upon himself the advance of senility, whitening of hair, etc. Since his crisis he had adopted the habit of writing occasional notes on his psychical state. This is what he wrote on the 23rd December 1913 at Sèvres: Two months and more have passed since I wrote the preceding lines. During that period my health has been satisfactory; nevertheless I have wondered every day whether it would be my last. I am therefore hastening to write my memoir on infantile cholera. The cardiac intermittence has been more or less frequent, yet every day I have had periods of regular pulsations (58-66-72 per minute) as usual. The day before yesterday I contracted a bad cold, accompanied by a little fever. Wondering if it would degenerate into pneumonia, I faced anew the possibility of a near end, and I resumed the analysis of my thoughts, feelings, and sensations. As my 70 years draw near to their close, it seems to me that a feeling of satiety with life, what I call the "natural death instinct," is gently beginning to evolve.