HIGH-CLASS SHEEP-BREEDING. 83 



under certain influences (called the vital force) from the 

 carbonic acid of the air. 



The other constituent is water. 



It will be seen also, that in the animal feeding on these 

 vegetable substances, there exists in the blood, bones, 

 flesh, and wool, the same mineral substances ; and these 

 pass into them from the food taken by the animal. The 

 flesh of the animal is formed of albuminous or nitrogenous 

 compounds, which are assimilated from the like com- 

 pounds of the vegetable matters ; hence these compounds 

 are called flesh-forming flesh being merely a more highly 

 azotised form of the same materials. Likewise, the non- 

 nitrogenous portions, or constituents, of the plants which 

 are present in these, in the forms of starch, sugar, gum, 

 &c. which are hydro-carbons enter into the animal 

 organism, and, in the vital laboratory, are converted into 

 fat a more pure and concentrated form of hydro- 

 carbon ; hence they are called fat-forming. They are 

 also styled heat-giving, or respiratory, for the reason that, 

 while a portion of them are retained as fat, and go to 

 form the fatty tissues as well as the fat deposits, another 

 portion is burned in the animal system. The oxygen of 

 the atmosphere being inhaled, and coming in contact with 

 the hydro-carbon, a combustion takes place, from which 

 the heat of the animal is derived ; exactly on the same 

 principle that coal (a hydro-carbon) is burned in a fur- 

 nace, or tallow, grease, or oil, is burned in a lamp. The 

 result of this combustion is carbonic acid gas, which is 

 exhaled. 



From this the very great importance of attention to the 

 food of animals will be self-evident. The structure of the 

 animal, its bones, nerves, flesh, fat, and wool, are depen- 

 dent on it for their development and quality. Not only 

 must animals be furnished with a given quantity of food, 



o 2 



