"It is evident, therefore, that substances that exhibit tlie phenomena of 

 cyclization and hysteresis in tlie living organism can do so only under condi- 

 tions of total or partial preliminary loss of the ability to be metabolized. 



"Thus, the theory of cyclization, which ignores metabolism, that funda- 

 mental quality of life, is entirely unacceptable from the mcthodologic viewpoint, 

 as are in general all theories that attempt to understand individual evolution 

 and its mechanisms from the viewpoint of the law of entropy" (A. V. Nagorniy, 

 1940). 



The valuable experimental material obtained by A. V. Balgoveshenskiy 

 retains its significance for the age-associated and evolutionary biochemistry of 

 plants. Its interpretation must bear in mind the fact that the increase in cyclic 

 compounds in the ontogenesis of plants is the result and not the cause of age- 

 linked changes in metabolism. In addition to this, even in plants the relation- 

 ships are far from being as simple as the cyclization theory would make them. 

 As far as the animal organism is concerned, we find that the changes in the com- 

 position of the protoplasm that are actually observed are extremely complex 

 and do not fit into the simplified schema of cyclization. 



The problem of the age-associated development of plants was studied by 

 N. P. Krenke (1933-1939) and his pupils (1933-1950). He advanced his theory 

 of "cyclic aging and rejuvenescence" of plant organisms. In his fundamental 

 monograph, which appeared posthumously (in 1940), he formulated the basic 

 elements of his theory in the following manner: 



" 1 . The individual inevitably grows old and dies. 



"2. Aging, i.e., changes in the age-associated condition, does not usually 

 agree with the calendar age of the individual. 



"3. Aging, and hence the duration of life, are dependent on evolutionary 

 factors but are greatly affected by the external conditions of development. 



"4. All phenomena in the organism are connected to some extent with its 

 age-associated state. 



"5. Aging proceeds without interruption but not uniformly both for the 

 individual as a whole in its various age-associated and phasic states and for the 

 individual parts and signs of the individual. 



"6. In the process of total individual aging, there is inevitably an uneven 

 cyclic rejuvenscence in the neoformation of the living elements of the individual. 

 But the absolute degree of this rejuvenescence progressively drops, i.e., aging is 

 reflected in a progressive decrease of rejuvenescence. 



"7. Rejuvenescence is the neoformation and development of young struc- 

 tures and substances and also the retardation of the aging of existing elements, 

 but not a restoration of the past. 



"8. The development of the organism is a struggle and unity of opposing 

 processes in it: aging and rejuvenation. 



"9. The age-associated condition of the parts of the individual is deter- 

 mined by the inherent and general age-associated state. The specific age- 

 associated condition is the result of the processes that have gone on from the 

 time of formation of the part in question, but these processes depend on the 



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