1174 THE PEOPLE'S FARM AND STOCK CYCLOPEDIA. 



then for other purposes, they are but little superior to carbohy- 

 drates, and far inferior to fat. 



Different Foods. We are now prepared to consider the 

 composition of different articles of food. It has been shown 

 that the chief constituents of all foods are : Albuminoids, or sub- 

 stances containing nitrogen; carbohydrates, substances such as 

 starch, sugar, etc., containing no nitrogen; fat, resembling car- 

 bohydrates, but richer in carbon; ash. 



The nitrogen in foods is not always in the form of albu- 

 minoids, but is sometimes contained in a class of substances 

 called by chemists amides. So little is yet known about these 

 substances that in this chapter we shall not attempt to make the 

 distinction between amides and true albuminoids, but shall class 

 all nitrogenous matter as albuminoids. Amides, however, have 

 not the feeding value of the true albuminoids, and in estimat- 

 ing the value of foods it should be remembered that in rich foods, 

 such as grains, oil cake, etc., nearly all the nitrogen is in the 

 form of albuminoids, while in poor foods, such as straw and 

 roots, a considerable portion of the nitrogen sometimes as much 

 as half is in the form of amides. In immature plants the 

 amount of amides is usually considerably greater than in those 

 more mature. The difference in value of rich and poor foods is, 

 for this reason, usually considerably greater than the tables of 

 analysis show. 



Carbohydrates are usually divided into "soluble carbohy- 

 drates" and "crude fiber;" they are of the same character and 

 composition, but the soluble carbohydrates are more digestible, 

 and therefore more valuable than crude fiber. 



Many writers in speaking of food constituents designate the 

 albuminoids as "flesh formers," and carbohydrates and fat as 

 "heat producers." From what has been already shown it is 

 evident that this is not strictly correct, as albuminoids are capa- 

 ble of being used for the production of heat, and carbohydrates 

 and fat, while not convertible into muscle, are convertible 

 into fat. 



All foods contain some water ; even those usually called dry, 

 such as hay, straw, and grains, contain from ten to fifteen per cent 



