CHAPTER II, 
FEEDING, AND THE COMPAEATIVE VALUE OF THE DIFFEEENT FOODS. 
T N rearing fowls with any prospect of profit, a correct system of feeding is of the 
first importance, and it is most desirable to enter thus early on the subject, 
especially as the scientific principles of feeding are so frequently ignored. 
The purposes served by food when taken into the body are of several distinct 
kinds : there is the production of animal warmth ; the provision for the growth and 
waste of the body ; the supply of mineral materials for the bones, and saline sub- 
stances for the blood ; and, lastly, the supply of fat. 
The warmth natural to living animals depends upon the consumption of a certain 
portion of the food in the process of breathing. The substances consumed in this 
manner are chiefly those which contain a large quantity of carbon, which passes off 
in the breath, in the form of carbonic acid. 
The most important warmth-giving foods are starch, sugar, gum, the softer 
fibres of plants, and oily or fatty substances. As the natural warmth of an animal 
in health remains the same at all times, it necessarily follows that a larger supply 
of warmth-giving food is required in cold situations than in those which are warm. 
To supply the materials required for the growth of young animals and for the 
formation of eggs, as well as those required to repair the waste arising from the 
movements of the living body, a second variety of food is required ; for the starch 
and other substances before enumerated have been proved, by direct experiment, 
to have not the slightest action in supplying these wants. Substances possessing 
this power are termed flesh-forming foods. The most important are the gluten, 
and similar substances, existing in variable quantities in different grains ; in large 
proportion in the varieties of pulse, as beans, peas, &c. ; and in the materials 
which form the solid parts of the flesh of animals, of eggs, of milk, &c. In con- 
sequence of these substances containing the element nitrogen, which is wanting in 
the other varieties of food, they are frequently termed nitrogenous foods ; whilst 
the fat-forming and warmth-giving are called carbonaceous foods. 
The mineral and the saline substances contained in the hones, and in other parts 
of the bodies of animals, occur in larger proportion in the bran than in the inner 
part of the grain. A due supply of bone-making and saline materials is absolutely 
requisite to the growth of a healthy animal ; as, if wanting in the food, the bones 
become soft, and the general health speedily fails. 
With regard to those substances which supply the materials for replacing the 
