CHAPTER V 



THE COMPOUNDS OF ANIMAL NUTRITION, 

 CONTINUED THE NITROGEN COMPOUNDS 



THE nitrogen compounds of the vegetable and animal 

 kingdoms have received much attention from scientific 

 investigators and writers during the past fifty years. It 

 has been generally taught that certain members of this 

 class of substances are the ones most important in the 

 domain of animal nutrition, and many writers have given 

 to these a prominent place in discussing the relative 

 value of feeding-stuffs and have almost ignored the other 

 nutrients. It is now conceded that relatively the func- 

 tion and value of protein have been unduly magnified. 

 The present tendency is toward a fuller discussion of the 

 office and value of the non-nitrogenous bodies. 



59. The importance of protein. There can scarcely 

 be any disagreement, however, concerning the general 

 proposition that the proteins play a leading part in the 

 processes and economy of animal nutrition. This is true 

 for several reasons: 



(1) The nitrogen compounds are those fundamental 

 to the energies of the living cells which make up the tis- 

 sues of plants and animals. The basic substance of the 

 active cell is protoplasm, a complex nitrogenous body, 

 which Huxley called "the physical basis of life." Around 

 this primal substance seem to center all vital activities, 

 especially the transformation of the raw materials of the 

 inorganic world into the organized structures of life. 



(47) 



