Protein — Proffuls 



55 



modified eitlier by various external agencies, or are the 

 result of a union of proteids with compounds of another 

 class. More than all, the classification here used seems 

 to be fairly well adapted to the effort of making clear 

 to the beginner or unscientific reader this most difficult 

 division of our subject. No apology is offered for the 

 hard names that are used. They are the only ones 

 available, and as they have the merit of conciseness, it 

 is hoped that in time they will come into an intelligent 

 popular use. These are: 



f Simple . . 

 Modified, 



Protein. To- 

 tal nitrogen 

 compounds . 



Proteids 



r Albumins 

 < Globulins 

 I and allies 



/ Derived 

 ( Compound 



- Non-proteids 



Collagens or 

 gelatinoids 



Extractives 



Amides, 



a m i d o , 



acids, etc. 



Other nitrogen compounds are included with the 

 protein by the present methods of estimation, such as 

 alkaloids and nitrates, but these are so uncommon in 

 feeding stuffs, or are present in such small quantities, 

 that they may be safely ignored. 



PROTEIN — THE PROTEIDS 



Proteids are the main and important nitrogen com- 

 pounds either in the plant or in the animal. The pro- 

 tein of seeds contains little else than proteids, while 

 that of young fodder plants and especially of roots 



