580 SESSION VI. DISCUSSION 



theory gives a complete answer to the question of what life is and how it arose in nature. 

 I must therefore point out that, in 1949, we published {Dokl. Akad. Nauk S.S.S.R., 

 Vol. 68), work in which it was shown that any organism develops in accordance with the 

 law of chain kinetics and the fundamental assumptions of the theory of the evolution of 

 chain processes in nature. 



This theory supplements and makes more precise the theory of coacervates. The syn- 

 thesis of these two theories, it seems to us, gives a deeper and better developed answer to 

 the question of what life is and how it arose. In the testimony of the professors of the 

 Moscow State University very favourable mention is made of our theory of the evolution 

 of chain processes in nature and their connection with biological processes. Oparin also 

 gave a favourable account of my work and I value this most particularly. For example, 

 he emphasizes the novelty of the conception of the alteration of chain chemical processes 

 in the period preceding the origm of hfe. 



Oparin agrees with us that, at this period, a very important part was played by reactions 

 which proceeded via intermediate compounds (active products). By reacting with the 

 starting products, these active products can give rise to final products and partially regain 

 their own form (i.e. be regenerated). In this case the reactions which proceed via an inter- 

 mediate compound assume the character of a cyclical chain reaction, at first of the radical, 

 and then of a more complicated, prebiological type, but already with the participation of 

 proteins. This seems to be the prototype of metabolism. 



An extremely important peculiarity of such reactions is that, depending on the nature 

 of the intermediate products, the reactions may be of a different nature, even though the 

 starting products may be the same. As a result, such reactions may compete with one 

 another in such a way that one or several reactions 'predominate' over the others, directing 

 the process of chemical transformation along a path which is determined by the particular 

 collection of intermediate products present. Owing to the cyclical nature which chain 

 processes acquire in the course of time, there also occurs a transmission of the peculiarities 

 and character of the process from cycle to cycle, so that this cyclical nature is the proto- 

 type of inheritance. Finally, under the influence of various conditions in the environment, 

 in particular in the nature of the original nutrients, the character of the cycle can change. 

 This corresponds to mutation. 



Thus we have the fundamental elements required for the Darwinian evolution of 

 chemical transformation in the pre-biological period. 



We have given a detailed analysis of the consequences which flow from this concept 

 and demonstrated the possibihty of the origin of life, i.e. chain reactions accompanied by 

 the growth and self-dispersal of colloidal protein systems with a monophasic or diphasic 

 structure (nucleus and envelope). 



In doing so we have given great attention to elucidating the effect of the environment 

 on the nature of the processes which occur within these colloidal systems and have, with 

 a fair degree of certainty, demonstrated the possibility of changes occurring within the 

 nucleus when the conditions of the external environment change. Oparin emphasizes all 

 this in his reviews. In his new and extremely interesting book he only gives a general 

 favourable reference to our kinetic conception and makes some critical remarks in con- 

 nection with the theory, but does not give even the shortest explanation of the essential 

 nature of this theory, such as is necessary even for readers who know Russian. This gives 

 rise to even greater difficulties for those who read Oparin's book in English, since work is 

 criticized which is unknown to them and which is hard to find in hterature outside this 

 country. In his critical remarks Oparin wrongly states that we limit ourselves to the 

 consideration of radical chain processes. This is in contradiction to what he has written 

 in his own reviews. Other comments of a critical nature can also easily be refuted. Un- 

 fortunately we cannot deal in greater detail with the essential features of our theory. 

 Under these circumstance it would be very important if we could find, before the end of 

 this Symposium, some organizational possibility for assessing both of the two theories 

 discussed and the connection between them. 



G. A. Kritskiï (U.S.S.R.): 



I should like to make two comments on the problems under consideration. 



I. The available evidence allows us to note that in processes of selection, except the 



