THE PROTEINS 45 



proportion varies so does the composition and 

 character of the proteins ; and the proportion of 

 amino-acids which can be obtained from proteins 

 affords no clue to the mode of their arrangement in 

 the protein molecule.* Albumoses and peptones are 

 units in the protein molecule of much higher 

 chemical constitution than the amino-acids from 

 which they are derived, indeed their constitution 

 is nearly as obscure and complex as that of protein 

 itself. Recently Fischer has, by chemical action, 

 chained together the amino-acids into substances 

 called peptides and polypeptides which give the 

 biuret reaction like true or natural peptones. A 

 continuance of such synthetic processes will probably 

 throw light on the mode of protein-formation in the 

 living organism. 



* Barker : loc. cit. 



