Plants require food to support them when growing, they 

 find it in the air and in the soil The food of animals consist 

 of any and all substances which can be taken into the system 

 and, which contribute toward supporting life, or causing growth, 

 and is prepared for them by plants. A food may be comp/cte 

 that is capable of furnishing all that an animal requires, as 

 grass, or it may be incomplete or not capable of sustaining life, 

 when fed alone, e. g.. starch, sugar, oil, etc. These are just as 

 much food, however, as grass. 



It has been intimated already that plants are made up of 

 unlike parts, or constituents, and the first step towards and un- 

 derstanding of the use of food is to know what the food is, the 

 chemist must be consulted in determining this. It is true that the 

 eye detects differences in the external appearance of food, but if 

 some one should ask for the exact difference between corn meal 

 and shorts it would be impossible to answer him, without know- 

 ing the chemical composition of the two. In the machine shop 

 the mechanic learns the peculiarities of different machines by 

 taking them apart and noting their construction. In the labora- 

 tory the chemist learns the characteristics of various plants and 

 fodders by taking them apart, so to speak, instead of the vise 

 he uses the crucible, in place of the monkey wrench he uses 

 various acids, alkalies, etc., to tear apart the plant and separate 

 it into the constituents of which it is made up ; instead of the 

 accurate rule measuring to the to^oo P^J't of ^^ i^^ch he uses de- 

 licate balances, which weigh to the ^^^'502 P^^'t of an ounce. 

 The object of both the mechanic and the chemist is to get a 

 knowledge of the internal structure which simple inspection 

 cannot give. If plants were made up of but one kind ot male- 

 rial there would be no need of chemical analysis. Uut such is 

 not the case. If we press out the juice of a stalk of corn and 

 evaporate it we get sugar ; if the dried kernels are ground into 

 a paste, with water, and then washed and manipulated in cer- 

 tain ways a large per cent of starch is obtained. If another 

 sample of this corn meal is boiled with elher and the ether 

 poured off into a clean dish and evaporated there will be found a 

 clear yellowish oil, or fat, which the ether dissolved out of the corn. 

 If wheat dough is washed until the starch is removed, a tough, 

 sticky mass is left, this is known ■A%glutc7i. These four substances 

 represent the most important constituents found in fodders. 



7 



