COMPOSITION OF PLANTS AND ANIMALS 259 



old ones the most. Common corn fodder contains about 

 3 per cent of ash, alfalfa about 10 per cent, and some of the 

 roots 1 per cent. The ash in plants is of value for food, if not 

 too abundant. Hogs raised on feeds containing but little 

 mineral matter, such as corn, for example, do not have as 

 good bone or do not feed so well as when the corn is supple- 

 mented with other feeds containing more ash. 



Protein in the plant is a combination in which nitrogen, 

 especially, plays a very important part, and is combined with 

 carbon, oxygen, hydrogen, and sulphur. There are dif- 

 ferent forms of protein, but we do not need to concern our- 

 selves about that here. This substance is not usually abun- 

 dant all through the plant. Rough stalks contain but little. 

 Prairie grass hay has about 6 per cent, red clover 12 per cent, 

 and cotton seed 18^ per cent. The growing plant usually 

 has its greatest amount of protein when in bloom. Seeds 

 are richest in this substance, for as the plant matures it 

 shifts the protein to some extent from stalk to seed. In some 

 of our mills where seeds are crushed or otherwise treated 

 and the hulls removed, by-products, very rich in protein, 

 are produced. Cottonseed meal is a good example. Protein, 

 whether used to feed plants or animals, is the highest priced 

 food constituent the farmer can buy, when we consider the 

 price he must pay on the market. This is because it contains 

 BO much of the valuable element, nitrogen. 



The carbohydrates are combinations of carbon, hydrogen, 

 and oxygen, and contain no nitrogen. These are the most 

 abundant of our food substances in plants. There are two 

 kinds of carbohydrates, one known as nitrogen-free extract, 

 consisting mostly of sugar, starch, and gums; the other called 

 fiber or crude fiber, making up the woody part of the plant. 

 Most of the fiber is cellulose, the material composing the 



