THE CHEMICAL BASIS OF LIFE 



There being no evidence to justify us in assum- 

 ing that life is due, primarily, either to specific 

 details of physical structure or to extreme com- 

 plications of molecular structure, we find our- 

 selves driven to the conclusion that life must be 

 due to some comparatively simple principle of 

 chemistry which has not yet been discovered. To 

 find a clue to this we must investigate the molecu- 

 lar structure of proteins, because these appear to 

 constitute the basis of all life processes. Fats 

 and carbohydrates, although formed during pro- 

 tein metabolism, are evidently nothing more than 

 by-products which may be useful at times for 

 fuel or skeletal support but do not enter into the 

 molecular structure of living matter in such a 

 manner as to exert any directing influence there- 

 upon. 



Protein substances, upon hydrolytic decomposi- 

 tion, always yield as their principal cleavage 

 product a mixture of amino acids or their diketo- 

 piperazine derivatives, which may be represented 

 generally as follows : 



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