ORIGIN OF THE FIRST ORGANISMS 389 



molecule, ' multiplied ' so to speak more and more, so that 

 there was a steady increase on the surface of the Earth in 

 the amount of the compounds ^vhich belonged to the series 

 of optical isomers in question. A detailed examination of 

 the subject shows, however, that the matter is considerably 

 more complicated. 



W. Kuhn^^ in his day undertook a detailed analysis of all 

 the evidence then available concerning asymmetric synthesis. 

 He showed, in the first place, that a racemic mixture is 

 thermodynamically more stable than its separate optically 

 active components because the free energy is less in the 

 racemic mixture. Any mixture of optically active substances 

 will, therefore, tend to racemise and lose its optical activity. 

 In any synthesis mediated by an asymmetric catalyst (e.g. 

 an enzyme) at first only one optical antipode will be formed 

 quickly. However, the other antipode is formed too, but 

 in an amount which is as many times smaller than that of 

 the first as the rate of the synthesis in the presence of the 

 catalyst is greater than the rate without the catalyst. This 

 will lead to the appearance of a certain asymmetry, a certain 

 inequality between the amounts of the dextro and laei^o anti- 

 podes. But as a true catalyst increases the rate of a reaction 

 and of the reverse reaction, after equilibrium has been 

 reached some of the product of the synthesis will be converted 

 into the starting substance giving rise, though very slowly, 

 to fresh amounts of the antipode which is synthesised without 

 the catalyst. Thus the whole system will tend towards the 

 racemic state and the optical activity which arose as a result 

 of the action of the asymmetric catalyst will gradually get 

 weaker as may, in fact, be demonstrated by experiment.®* 



Thus the asymmetry which arose in an enclosed system 

 owing to the activity of any isolated reaction must have been 

 a temporary phenomenon and could not have served as a 

 basis for the formation of the very complete and constant 

 asvmmetry of protoplasm. 



The continual formation of only one optical antipode can 

 only occur in open systems on the basis of a definitely 

 organised network of reactions, the rates of which are very 

 accurately related to one another. Under such conditions, 

 when there is a definite sequence of processes, racemisation 



