32 MANUAL OF CATTLE-FEEDING. 



tained in dried blood and flesh-meal (tlie residue from tlie 

 preparation of '' Extract of meat,") are equivalent in imtri- 

 tive effect to vegetable albuminoids. 



It is possible tliat we onglit to regard gliadin as forming 

 an exception to the equivalence of the albuminoids on ac- 

 count of its great likeness to animal glue, or gelatin, the 

 latter having been shov^n by Yoit^ to be incapable of per- 

 forming all the functions of protein in the food. 



Importance. — This close nnitual relation and easy con- 

 vertibility of the albuminoids has the highest signilicance 

 for animal nutrition. 



As we have seen, the most important solid components 

 of the animal body are the albuminoids and related bodies. 

 It is these which constitute its muscles, tendons, nerves, 

 in fact all its working machinery. 



Now, so far as we know, the animal organism has no 

 power to originate a particle of these substances. 



Its sole source of them is, in the herbivora directly^and 

 in the carnivora indirectly, the albuminoids of the plant. 

 Tliese, by virtue of their great similarity to the animal al- 

 bununoids, are readily altered into them and become part 

 of the body. They arc hence indispensable elementb of 

 any food, and likewise the most important, since, while 

 they can, to a certain extent, take the place of the non- 

 nitrogenous nutrients, none of the latter can pobbibly re- 

 place the albuminoids; and they are of all the greater 

 importance because, while the animal body is, to so large 

 m extent, composed of them, they are found in compara- 

 ti%ly small quantity in most parts of plants. 



Evidently, then, the proportion of albuminoids which a 

 fodder contains is an important element in determining its 



* Zeitschrif 1 1 Biologie, VIIL , 297. 



