п. PHYSIOLOGY OF AGING BEFORE 

 THE OCTOBER REVOLUTION [tr.: 1917] 



(Establishment of the first scientific schools and theories in 

 ontophysiology) 



A remarkable Russian biologist, the author (with A. O. Kovalevskiy) of evolu- 

 tionary embryology and the founder of the theory of phagocytosis, I. I. 

 Mechnikov investigated the problem of longevity for more than 40 years and 

 established a valuable theory of aging. He published 39 experimental studies 

 and monographs in this area, among them such fundamental and now classic 

 works as "Studies of the nature of man" (1903-1904), "Studies of optimism" 

 (1907), "Prolongation of life" (1912), "Forty years of searching for a rational 

 Weltanschauung" (1913), and others. 



Mechnikov expressed the remarkable thought that "human life fails half- 

 way along its course, and our old age is a disease, which must be treated, like 

 any other." This idea is basic to many of his investigations, which were the 

 first to introduce the concepts of pathological and physiological aging into 

 science. He sought to give man an opportunity to achieve a normal physio- 

 logical old age, without senility or deep degradation of physical and intellectual 

 powers. He conjectured that attainment of extreme old age would eliminate 

 that disharmony of the nature of man which he so clearly depicted in the 

 following words: "Our strong desire to live finds itself contradicted by the weak- 

 ness of old age and the briefness of life. This is the greatest disharmony of 

 human nature." When the organism is "used up," man accepts death as 

 happily and peacefully as he always accepts rest and sleep after a fruitful and 

 productive day of work. It must be noted, however, that this last vision ex- 

 pressed by Mechnikov is not fully justified. Even very old people do not lose 

 their instinct to live. 



In his theory of aging and death, Mechnikov combined the concept of an 

 intoxication of the organism that continued to increase with age (attributable, 

 to a certain extent, to a decay of the intestinal microflora) with the idea of the 

 non-uniform sensitivity of different tissues to this intoxication. The "noble" 

 (most valuable and delicate, tissues, especially the parenchyma of the brain and 

 heart, kidneys and liver, are very susceptible to poisons; connective tissue, on 

 the other hand, retains its full value and ability to multiply to advance old age. 

 Hence the "struggle," in the aging organism, between the tissues, the growth of 

 the connective tissue and its supplantation of the "noble" tissues, which is ac- 

 companied by a consumption of the dying cells of the ner\^e, muscle, and 

 glandular tissues by macrophages that are activated during old age. 



