86 THE CHEMICAL CONSTITUTION OF THE PROTEINS 



the more complex polypeptides the products of partial hydrolysis by 

 enzymes require examination. We may, however, soon expect that the 

 extension of the study of the higher polypeptides, more especially of 

 the mixed polypeptides, will lead to the separation and isolation of 

 those complexes long known as the proteoses and peptones from the 

 products of partial hydrolysis of the proteins. Our data seem to show 

 that they are more simple than was previously supposed, for polypeptides 

 containing four and six units, of which tyrosine or cystine is one, can 

 be salted out with ammonium sulphate, by which means the proteoses 

 are now characterised. 



