192 BACTERIOLOGICAL AND ENZYME CHEMISTRY 



The further decomposition of peptones results in the 

 formation first of substances which have still a complicated 

 composition, and which are known as polypeptides, and 

 finally into substances of a simpler character, viz., ammo 

 acids, of which amino-acetic acid or glycocoll, CH 2 NH 2 COOH, 

 is a prototype. The separation and investigation of these 

 is a task for the experienced organic chemist, and its details 

 cannot profitably be fully discussed here. 



The whole subject has been brilliantly investigated by 

 Emil Fischer and his colleagues, who have not only devised 

 methods for separating and identifying amino-acids, but 

 have also been enabled to synthesise a number of polypeptides, 

 whose complexity approaches in certain cases the complexity 

 of the peptone molecule, and which are even capable of being 

 broken down again into simpler substances by the action of 

 trypsin. 



Certain American investigators have announced that they 

 were able to synthesise peptone-like bodies by the action of 

 trypsin on polypeptides. However this may be, it is clear 

 that in this direction we must look for any definite know- 

 ledge as to the ultimate structure of the albumin molecule 

 or its derivatives, and a brief account of the chief products 

 separated or prepared by Emil Fischer and others, and of the 

 methods used in their researches, will be of interest and value 

 as affording a basis for the classification of the very numerous 

 bodies related to albumin. 



PRIMARY DISINTEGRATION PRODUCTS OP ALBUMIN 



Fischer made use of three chief methods for separating 

 amino-acids : 



1. The acids are converted into ethyl esters which are 

 separated by fractional distillation under the lowest possible 

 pressure. The following description will indicate in outline 

 the practical carrying out of the method. 



