CHAPTER II 
THE COMPOSITION OF ANIMALS 
WE find, in general, similar substances in the animal body as in 
plants, but the relation between the different groups of components 
differs, and some substances found in animals do not exist in plants, 
or differ in their properties from the corresponding plant constit- 
uents. Animals are composed of water, protein bodies, fat and 
mineral matter; the protein, or protein and fat, make up the largest 
proportions of the dry matter of animals, while carbohydrates are 
present in only small amounts. We have seen that the dry matter of 
plants, on the other hand, is largely composed of carbohydrates, 
and that protein is, as a rule, present in relatively small amounts. 
The composition of different farm animals varies according 
to their body condition, especially the amount of fat which they 
carry. The classic experiments of Lawes and Gilbert which were 
conducted about 1850 at the Rothamsted Experiment Station, Eng- 
land, furnished the first accurate information on this point; their 
findings have been corroborated during later years by investigations 
at the Maine and Missouri Experiment Stations and elsewhere. 
The following summary table shows the percentage composition of 
live animals, less contents of stomach and intestines: 
Composition of Live Animals, in Per Cent. (Lawes and Gilbert.) 
Water Fat Protein Ash 
Fat calf.......... 002. e eee ee . 646 14.1 16.5 4.8 
Steer, well fed.............. 66.2 8.7. 19.2 5.9 
half fates is csias cnr es we 59.0 17.5 18.3 5.2 
fAbiecccccuniey Ae ead 49.5 30.5 15.6 44 
Sheep, lean................. 67.5 10.2 + 18.3 4.0 
well fed................ 63.2 15.5 17.4 3.9 
half fed vivicccc see ay euky 58.9 21.3 16.0 3.8 
LBC s.iiscoa agli eaaecnaisiawtt es 50.9 31.9 13.9 3.3 
very fat..........0000ee 43.3 41.4 12.2 3.1 
Swine, well fed.............. 57.9 24.2 15.0 2.9 
fatioc.ct santana ts ke tes 43.9 42.3 11.9 1.9 
‘The figures given in the table show that the fatter an animal is, 
_ the less water, protein, and ash will it contain; also, that the per- 
centage of fat in the body of a steer ‘may range from at least 8 to 30 
per cent, that in a sheep from 10 to 41 per cent, and that in a hog 
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