CHAPTER VII 



THE COMPOSITION OF THE BODIES OF FARM ANIMALS 



THE principal compounds existing in the bodies of 

 our farm animals have been quite fully considered on 

 preceding pages. It now remains for us to learn some- 

 thing of the proportions of these substances that are 

 needed in constructing the carcasses and other tissues 

 of steers, sheep and swine; for it is about these spe- 

 cies that we have the most extensive and accurate 

 knowledge as related to chemical composition. Cer- 

 tainly such knowledge is important. The animal is 

 the direct product of food, and before we can consider 

 intelligently the functions of food nutrients and the 

 ways in which they are made to fulfil their offices, we 

 must understand what is to be done. So far, then, as 

 it is a matter of construction, what must be accom- 

 plished by the use of food in building the body of an 

 animal ? ' It has doubtless become evident from fore- 

 going statements that many compounds are common 

 to the vegetable and the animal kingdoms. The chem- 

 ical constituents in plants and animals are classified in 

 the same way, also; viz., water, ash, or mineral com- 

 pounds, protein, carbohydrates, and fats. Here the 

 similarity stops, for the proportions of these classes 

 as found in the fat steer and in the stalk of maize are 



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