SELF-RENEWAL OF THE SYSTEMS 355 



network of reactions carried out within it while, conversely, 

 the network was determined by the organisation of the system 

 as a whole. If the system was not co-ordinated but, neverthe- 

 less, interacted with the external medium, it would very 

 quickly disintegrate and disappear as an individual forma- 

 tion. If the interaction between the system and the medium 

 stopped for any reason, then the system would become static 

 and, as such, cease to take part in the general process of 

 evolution. 



For example, if the stability of the drop depended on the 

 formation of strong surface layers and if these disintegrated 

 spontaneously at a definite rate but could be built up again 

 in the course of chemical reactions within the drop, then the 

 stability of the drop would depend on the relative rates of 

 disintegration and reconstruction of the surface layers. If 

 the chemical reactions took place fast enough in the drop, 

 with a corresponding fast rate of formation of the firm surface 

 layers, then the dynamic stability of the drop might also be 

 very great. In this case an increase in the rate of the chemical 

 reactions within the drop wotild have favoured its stability. 

 The increased rate of reaction within a drop would increase 

 its stability, and prolong its survival under such conditions. 

 If the rate of formation of the surface layers became less than 

 the rate of their destruction such a drop would soon dis- 

 integrate. Finally, if the surface layers themselves were very 

 strong and stable but not associated with any cheinical 

 reactions within the drop, then such static colloidal systems 

 would be excluded from the course of the evolutionary 

 process. 



Accordingly, as a result of the directed evolution of the 

 original systems, their stability took on a more and more 

 dynamic character. The coacervate drops were gradually 

 transformed into open systems the very existence of which, 

 under the given conditions of the external medium, depended 

 on the organisation of the processes taking place within them. 

 In other words, there arose systems in which there was a back- 

 ground of continuous processes of self-renewal and which 

 could preserve themselves and exist for a long period on the 

 basis of constant interaction with the external medium. The 

 origin of this capacity for self-preservation may be regarded 



