591 FARM STOCK, BREEDING, AND FEEDING. 
into two grand divisions, viz., the nitrogenous, or blood and 
flesh forming matters, and the non-nitrogenous or the fat- 
forming, being the material which keeps up the heat of the 
body, gives power of motion and respiration. These several 
foods are exemplified in the milk of the female, which em- 
braces them all. It is also contained in the eggs of birds, 
but in this latter, the nitrogenous is in the greatest abun- 
dance. Some vegetables tend to form fat, whilst others 
form flesh and blood. Vegetables are good or indifferent as 
food for man and animals, in proportion as they contain 
nitrogen or carbon, flesh or fat, cheese or butter forming 
substances. 
Of all the vegetables grown by man, the wheat grain 
contains the greatest assimilation to the mother’s milk, as it 
contains gluten and starch, the principal matters, or as they 
may be termed, cheese and butter. Dr. Playfair has said in 
his lectures , — “ Casein is precisely the same in composition 
as animal flesh, and hence supplies matter adapted for the 
growth of the body. Butter and sugar are destined for the 
support of respiration and consequent maintenance of animal 
heat. Butter is a substance admirably suited for the pur- 
pose ; for, being of a combustible nature, it yields much 
heat by its union with oxygen. Sugar also is well adapted 
for the support of respiration, from causes which have been 
explained.” “The milk of the cow contains much casein 
and butter, and less sugar than other animals. The ashes of 
milk consist principally of common salt and the earth of 
bones. The soda of the common salt is necesary for the 
formation of bile, whilst its muriatic acid aids in the process 
of digestion. 
Feeding on milk, or on cheese and butter with breads is 
taking the most nourishing food that can be had for man ; 
but the kind of food for man, or the lower animals, must be 
varied in accordance to the age of the animal, and in agree- 
ment with what is desired to be accomplished. A growing 
animal requires much nitrogenous food, and less of the 
carbonaceous ; the one will build up the frame, and the 
other add the fat, warmth, respiration, and motion. 
An animal having been built up to its full size, requires 
only its parts to be kept up, and the exhaustion of fat 
supplied daily ; also, as fuel for the supply of warmth, loco- 
motion, and respiration ; these latter functions are of vital 
consequence, and first call on the food for support. If any 
carbonaceous matter is left from these supplies, then will 
fat accumulate on the body, and not until then ; should 
there not be sufficient food supplied of the proper kind wanted. 
