COMPOSITION OF FEEDING STUFFS. 191 



eral matter, while the muscles and other parts of the 

 body contain only small amounts; it must not be con- 

 cluded, however, that the ash materials are of minor im- 

 portance for this reason; both the young and full grown 

 animals require a constant supply of ash materials in 

 their food; if the food should not contain a certain mini- 

 mum amount of ash materials, and of various compounds 

 contained therein which are essential to life, the animal 

 will turn sick very soon, and if the deficiency is not 

 made up will die, no matter how much of other food com- 

 ponents is supplied. As both ash and water are either 

 present in sufficient quantities in feeding stuffs, or can 

 be easily supplied, the feeder does not ordinarily need 

 to give much thought to these components in the selec- 

 tion of foods for his stock. 



Protein is not the name of any single substance, but 

 for a large group of very complex substances that have 

 certain characteristics in common, the more important 

 of which is that they all contain the element nitrogen. 

 Hence these substances are also known as nitrogenous 

 components. The most important protein substances 

 found in the animal body are: lean meat, fibrin, all kinds 

 of tendons, ligaments, nerves, skin, brain, in fact the 

 entire working machinery of the animal body. The casein 

 of milk and the white of the egg are, furthermore, protein 

 substances. It is evident from the enumeration made that 

 protein is to the animal body what the word implies, the 

 most important, the first. 



Fat is a familiar component of the animal body; it 

 is distributed throughout the body in ordinary cases, but 

 is found deposited on certain organs, or under the skin, 

 in thick layers, in the case of very fat animals. 



The animal cannot, as is well known, live on air; 

 it must manufacture its body substances and products 

 from the food it eats, hence the next subject for consider- 

 ation should be: 



Composition of Feeding Stuffs. 



The feeding stuffs used for the nutrition of our farm 

 animals are composed of similar compounds as those 

 which are found in the body of the animal itself, although 

 the components in the two cases are rarely identical, 

 but can be distinguished from each other in most cases 

 by certain chemical reactions. The animal body through 

 its vital functions has the faculty of changing the various 

 food substances which it finds in the food In such a way 



