THE FEEDING OF ANIMALS 275 



phosphorus, potassium, sodium, calcium, magnesium, iron, 

 manganese, silicon, chlorine, and fluorine. The line on which 

 feeds are divided into the two classes just mentioned is not 

 well established. 



Both of these classes contain all of the elements named 

 above. However, we rarely speak singly of the carbon, hy- 

 drogen, oxygen, and nitrogen which foods contain, but of the 

 compounds which they form. In speaking of the composition 

 of a feeding stuff we usually mention six things; namely, 

 water, ash, protein, crude fibre, nitrogen-free extract, and fat. 



It is well known that all green plants contain much water. 

 Water constitutes about eighty per cent, of the weight of 

 green corn plants. Timothy hay has about fifteen per cent, 

 and dry corn about ten per cent, of moisture. When this water 

 is removed by heating in an oven at a temperature a little above 

 boiling, the dry material left is referred to as dry matter. 



The ash of the plants is what is left after they are burned. 

 If we were to burn a hundred pounds of corn kernels there 

 would be left about one and a half pounds of ashes. The 

 other ninety-eight and one-half pounds would have passed 

 into the air as gases. Of the elements mentioned above, all 

 would be left in the ashes except the carbon, hydrogen, oxy- 

 gen, nitrogen, and chlorine. The elements that are left in the 

 ashes are called mineral matter. Different feeds contain dif- 

 ferent amounts of mineral matter. This mineral matter is 

 very necessary for animals. Lime and phosphorus help to 

 make bone; iron makes the blood red; chlorine and sodium 

 help in digestion; and so the various other elements serve 

 different purposes. 



Protein is the name given to the different forms in which 

 nitrogen is found in feeds. Protein is the substance which 



