258 BEGINNINGS IN ANIMAL HUSBANDRY 



of these unite to form carbon dioxide, or carbonic acid gas, 

 which the plant breathes in through the pores of the leaves. 

 This gas in the plant goes through a change, and the oxygen 

 is breathed out, and the carbon is left to be made up into the 

 solid part of the plant. 



Nitrogen in the form of a compound is taken up by the 

 plant through its roots; but plants of the legume group, such 

 as the clovers aided by certain bacteria, have the power of 

 using the nitrogen in the soil atmosphere. Nitrogen is a 

 highly valued plant food, and the farmer often purchases it 

 in fertilizer at a good price. These different elements unite 

 with one or more others in the plant, and form combinations 

 which are familiar to us under various names. Of these, the 

 following are important when we come to consider the plant 

 as food. 



Water is a combination of hydrogen and oxygen. It is 

 found in all plants, and even in very dry hay. To get the 

 water entirely out of the plant, it must be driven out with 

 artificial heat. The amount of water in plants differs greatly. 

 Common timothy hay and red clover contain about 15 per 

 cent, and ordinary corn meal has a similar amount. About 

 80 per cent of green pasture grass is water, and some of our 

 roots, like the turnip, have 90 per cent. After the water is 

 driven from the plant by heat, what is -left is dry matter. 

 The water in the plant is worth no more than any other water, 

 its chief value being to carry food in solution through the 

 plant. 



Ash, or mineral matter of plants, we see in the ashes left 

 from burned wood. When we burn a plant, we destroy its 

 form, and all that which burns and disappears we call 

 organic matter. That which is left is ash, or inorganic 

 matter. There is much difference in the amount of ash in 

 plants. Green or very young plants contain the least, and 



