338 ORGANISATION IN SPACE AND TIME 



plasm in time on the basis of its derivation from the ordinary 

 chain mechanism. 



As an example of this we may cite N. Akulov's book The 

 theory of chain processes/^ a quarter of which is devoted to 

 our problem. The theoretical merit of this part of the book 

 lies in the adoption of a kinetic approach to the problems of 

 the evolution of chemical forms of the movement of matter 

 rather than a simplified explanation of this evolution in 

 terms of increasing complexity of structure. Akulov's factual 

 working out of the problem cannot, however, be held to be 

 successful for, instead of the chains of chemical transforma- 

 tions of different molecules, each of which is thermodynami- 

 cally stable, such as are characteristic of metabolism, he refers 

 to the chain reactions of radicals which are different in prin- 

 ciple, in which there is a ' multiplication ' of identical cycles 

 such as is found in chain reactions in gases. Also, in Akulov's 

 scheme, the co-ordination of reactions in time and space is 

 supposed to be able to exist, in principle, even in a homo- 

 geneous solution, whereas the organisation of protoplasm 

 corresponds more nearly to the sequence of chemical reactions 

 which takes place in an open stationary system. This requires 

 heterogeneity and the presence of a structure which secures 

 a definite distribution of the components of the system and 

 demarcation of the system from the external medium. 



A more reasonable outlook on the course of development 

 of * prebiological ' organic chemical processes has been sug- 

 gested by J. W. S. Pringle.^* Like Akulov, Pringle starts from 

 chain reactions of radicals. But as it is quite evident to him 

 that such chain reactions do not occur in contemporary 

 organisms, he assigns a part to them only in the early stages 

 of the evolutionary process. He considers that what character- 

 ises living things is a series of reactions in which the entropy 

 of the system is decreased at the expense of an increase of 

 entropy in the external medium. 



According to Pringle such a localised decrease in entropy 

 depends on the carrying out of autocatalytic reactions in 

 living systems. However, he uses the term ' autocatalysis ' 

 (only for lack of a better one) not in the usual sense (meaning 

 that each molecule of protein or nucleic acid gives rise 

 directly to another just like itself) but to refer to a dynamic 



