II. 



The polypeptide thoory teaches that the 

 amino acid groups occur in nature in the form of 

 long polypeptide chains. This theory offers at 

 least a partial explanation for the phenomenon 

 of growth, as well as for structural variation, 

 hut in its present form is inadequat3 in th^\t 

 it does not account for that definite morphology 

 which is possessed "by all living organisvns, nor 

 for spontaneous division with the transmission 

 of hereditary charact sristics to the progeny. 



There is, however, another type of struc 



ture, namely the helical spiral, which retains 



the 3ssential characteristics of both the ring 

 and the chain. 



