which the cortex is not in a position to overcome the 'inertia' both of the other 

 parts of the central nervous system subordinate to it and of the peripheral 

 systems. It is easy to understand that as a result of this conflict, the preservation 

 of the harmonicity of the whole becomes impracticable. This brings with it the 

 heterochronicity of age-associated evolution in the various parts of the organism, 

 and, as a finale, the picture of a vigorous mind in a helpless body, with the ter- 

 minal victory of the latter over the former" (1954). 



Nagorniy's ideas about the motive factors of ontogenesis represent the first 

 draft of a major theory, the development of which, as he himself understood, 

 required a great amount of subsequent work on the part of many research 

 groups. It is natural that some elements of Nagorniy's teachings will be sub- 

 jected to revision and amplification in this later work. Some weak aspects of 

 Nagorniy's concepts are to be found in a certain overrating of the significance of 

 the role of metaplasia as the underlying factor of age-associated changes in 

 organisms and a certain one-sided evaluation of the significance of thermody- 

 namic mechanisms in the development of the vital processes in ontogenesis. 

 Aside from this, however, contemporary ontophysiology knows how much it 

 owes to Nagorniy for his great contribution to the creation of this rapidly 

 developing branch of biological science. 



The future valid and complete theory of ontogenesis will doubdess take 

 into consideration all the great advances that have been made in the field of 

 age-associated physiology by many of its investigators. In the great outflow of 

 creative thought, in the rapid replacement of the sometimes very contradictory 

 and one-sided concepts of the age-associated development of the organism, it 

 has gradually become possible to select and critically evaluate many important 

 concepts and to enlarge them substantially. The individual elements of a full- 

 valued theory of ontogenesis will doubtless contain the thoughts and discoveries 

 of I. I. Mechnikov, M. S. Mil'man, A. A. Bogomolets, I. P. Pavlov, A. V. 

 Palladin, N. P. Krenke, A. V. Nagorniy, and a whole pleiad of eminent Russian 

 biologists and physicians. 



In the present brief review of the history of Russian age-associated physiol- 

 ogy, an effort has been made to present concisely the course of development of 

 this outgrowth of science. This review has shown how much has already been 

 accomplished in the creation of a fully satisfactory theory of ontogenesis and 

 what have been the premises for the establishment of this Russian science. 

 And it has also been made clear that much still remains to be done before we 

 can accomplish the noble tasks of the remarkable science of the causes of the 

 age-associated development of organisms and of ways of promoting longevity. 



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