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ment of the cell). This conviction led him to consider whether the 

 "genes of the science of heredity" - genes in the original sense - - and 

 enzymes could not be regarded as identical. His argument, in short, is 

 that this is really the case, and that by the introduction of this sup- 

 position, new light is thrown on the nature and on the action of genes 

 during ontogenesis, and also on the occurrence of fluctuating variabil- 

 ity and of mutations. 



