STOCK FOOD L99 



part of the animal's body. The undigested portion is 

 passed off as manure. 



195. Protein, Non-Nitrogenous Matter, and Mineral 

 Matter All Necessary Foods. — The nitrogen com- 

 pounds of animal bodies are built up only from the 

 nitrogen compounds of plants. The non-nitrogenous 

 matters of animal bodies are built up principally from 

 the non-nitrogenous matters of plants, though they 

 iii;i\ also be formed from the nitrogen compound-. 

 The mineral matter of animal bodies comes largely 

 from the mineral matter of plants. Animals, then, in 

 order to keep their bodies built up, must be supplied 

 with food containing protein, non-nitrogenous matter, 

 and mineral matter. The amount of mineral matter 

 required in animal bodies is SO small that there is 

 always enough in the ordinary supply of food. It if 

 not necessary to consider mineral matter as a food. 

 Salt is not considered i food, but merely ■ relish. 

 Protein and non-nitrogenous matter ire then the only 

 solid substances re need consider in selecting food for 

 animals. Protein builds up the muscles, nerves, blood, 

 bones, and all the nitrogen-containing parts of the 

 body. It may also help to form fat and keep the body 

 warm. Protein compounds may serve to build op ever] 

 part <>f the animal body, and animals may live on a 

 food made up exclusively of protein. Bui inch a diet is 

 hot good for the health of most domestic animals* 

 nitrogenous matters cannot build Dp the nitrogen com- 

 pounds of animal bodies and animals starve to death on 

 a diet of non-nitrogenous matter alone. But certain 

 amounts of non-nitrogenous matt, r- are necessary for 



