THE PRINCIPLE OF SELECTION 353 



the collection of these substances from the external medium. 

 Even so the molecules of the external medium must ha\e 

 passed selectively through the surface membrane of the drop 

 or been adsorbed selectively by the compounds contained in 

 it and reacted with them in one way or another, the products 

 of the reaction either being retained within the drop or 

 passing out of it back into the external medium. Although 

 these reactions took place very slowly and did not form an 

 interacting network of processes, and although the conditions 

 necessary for the prolonged existence and stability of the 

 coacervate drop were still not present, nevertheless, even at 

 this primitive stage of evolution of our original systems two 

 circumstances were manifest which ^vere of great importance 

 for the further development of matter. 



On the one hand the individual peculiarities of the 

 physico-chemical organisation of each separate coacervate 

 drop imposed a definite pattern on the chemical reactions 

 which took place within that drop. The presence in a given 

 drop of this or that compound or radical, the presence or ab- 

 sence of simple inorganic catalysts such as salts of iron, copper, 

 calcium, etc., the degree of concentration of protein-like 

 substances and other substances of high molecular weight 

 forming the coacervate, its particular structure, all these 

 affected the rate and direction of the various chemical 

 reactions which occurred within the given drop, all these 

 imparted a specific character to the chemical processes which 

 took place within it. Thus there appeared a certain con- 

 nection between the individual structure and organisation 

 of a given drop and the character of the chemical trans- 

 formation carried out within it. In other drops these trans- 

 formations occurred and were co-ordinated in different ways, 

 depending on the peculiarities of each particular drop. 



On the other hand, any chemical processes, even unco- 

 ordinated ones, occurring within a drop, and, even more, 

 any connected group of processes, could not be without effect 

 on its future. Some of them led to greater stability, to a 

 more prolonged existence of the coacervate system under the 

 conditions prevailing in the external medium. 



From this point of view they were advantageous, they were 

 of positive significance. On the other hand, other processes 



23 



