AKID AGEICULTUEE. 



317 



KOW THE 

 FOODS ARE 

 USED 



treated as a separate class in compounding a food 

 ration. The fats are dissolved by the chemist 

 Avith ether, which also dissolves some other sub- 

 stances, so they are put together in our tables 

 under the name of ether extract. 



In general the nitrogen substances are used 

 in processes of growth, to lay on muscle or in- 

 crease in size, so larger amounts of them are 

 used in rations for young, growing animals, or 

 for' breeding animals, or cows giving large 

 amounts of milk which is rich in nitrogen. The 

 carbo-hydrates produce energy, as work and heat, 

 and the fats both help to lay on fat and produce 

 heat. But the complete function of the classes 

 of food can by no means be so simply stated. 



Many have the idea that a fattening ration 

 should be especially rich in fat, but that does not 

 follow. It is known that the animal body may 

 break down and change the compounds, even con- 

 verting one into the other. Protein may yield 

 fat and heat, or the carbo-hydrates may be, and 

 are largely, used to store up fat in the body. The 

 feeder needs to supply his animals with each 

 kind of food in the proportion best adapted to 

 the kind of animal for the kind of results sought 



DETERMINED The amouut of different foods given to ani- 



mals which may be digested and used is deter- 

 mined by experiment, and we have only these 

 actual feeding trials, along with the analyses of 



BT EXFERI- 



