206 PRINCIPLES OF FEEDING 



and they will not seem so difficult. Have you ever made 

 chewing gum by chewing the grains of wheat? This 

 gum was made almost entirely of protein. It is called 

 gluten in the wheat. In cheese, it is called casein. In 

 the white of an egg, it is called albumen. Protein is found 

 in all the field grains, in hay, .in clover, in peas, and in 

 beans. It goes to form the flesh, the cartilage, the hair, 

 the wool, and the casein and albumen of milk. It forms 

 the material in the body that is used up when work is 

 performed. Carbohydrates are principally the sugars and 

 the starches. Granulated sugar is a pure crystallized car- 

 bohydrate. Potato is composed almost entirely of starch 

 and sugar. The potato is a carbohydrate. Nearly all 

 fruits and vegetables are carbohydrates. The grains have 

 some starch in them, and that part of them is carbohydrate. 

 The same may be said of hay, grass, and fodder. The 

 carbohydrates are chiefly valuable in keeping up the heat 

 of the body and in forming fat. 



Office of Protein and Carbohydrates. Protein and 

 carbohydrates may be likened to the coal that is put into 

 the steam engine to give it power to do work. When the 

 work is done, the substances are consumed or burned up. 

 It is an interesting fact that the carbohydrates are much 

 more easily consumed in the body than the proteins. 

 When the body has work to do, or uses up fuel in keeping 

 warm, it first calls on the carbohydrates for service. The 

 proteins are not used until the carbohydrates are largely 

 consumed; then the proteins are called on. If more car- 

 bohydrates be furnished than is necessary to keep the body 

 warm and to furnish the energy for work, the body stores 

 it up in the shape of fat. The dairy cow secretes it in the 



