256 THE PRINCIPLES OF AGRICULTURE 



constituents of the ration is appreciated by 

 all animals. If the ration is composed of 

 several fodders, these may be mixed in a uni- 

 form mass and this mixture fed continuously 

 for long periods of time. This is particularly 

 true of cattle and swine. 



SUGGESTIONS ON CHAPTER XV 



437a. By-products are secondary products which result from 

 the manufacture of a given product. Thus, buttermilk and skim- 

 med milk are by-products of butter-making, whey of cheese- 

 making, pomace of cider-making, bran of flour-making. Many 

 important by-products used in feeding animals result from the 

 manufacture of breakfast cereals, the manufacture of glucose 

 syrups, and the processes of brewing and distilling. 



442rt. The group takes its name from albumin, which is seen 

 in its purest and most common form in the white of egg. 

 The gluten or sticky part of the wheat kernel, the casein or 

 cheesy part of milk, and the muscular fibers of lean meat, are 

 also familiar examples of albuminoids. From the many forms 

 they assume, they are often spoken of as protein compounds, or 

 proteids. They are also often called nitrogenous substances (370). 



443a. The albuminoids are necessary to all the processes of 

 growth and reproduction ; and since most animal products, as 

 wool, flesh, eggs and milk, contain large amounts of nitrog- 

 enous matter, the albuminoids are likewise essential to pro- 

 duction as well as growth. When the members of this group 

 are decomposed or broken down, they give up heat, and, there- 

 fore, may be used to keep the animal warm (372). It is not 

 at all uncertain that they are not concerned in the forma- 

 tion and storing up of fat in the tissues and milk. 



445a. The word carbohydrate (written also carbhydrate) 

 means carbon-hydrate. The word hydrate signifies a substance 

 in which water combines with some other element : in the carbo- 

 hydrates, this other element is carbon. In all the carbohydrates, 



