LE EL AT Ne Oe LEER OS Me A ee ne fee ee Mle PRO ae Eee ena n 
EE E AARE E ne RES RR RR Te Sg TS S eet em PPIE ERE MER E ENIE LE MINE I ee EH AT ERE RITE UTR RR RR ERE U RSE erm 
1894.] Animal Mechanics. 563 
all of the factors concerned. We have seen that energy must 
be expended in work to convert vegetable substances into ani- 
mal substances, and this energy can only be obtained by tear- 
ing apart the vegetable compounds through the processes of 
digestion, and liberating theirstored energy. In this process 
the vegetable compounds of the food are resolved almost into 
their elements, and from these 
by means of the energy liberated, the proteids and fats of the 
ox are manufactured. 
The complex animal substances thus formed are continually 
undergoing change. The wear and tear of the animal ma- 
chine involves a disintegration of its organic substance, and 
its stored energy is liberated as heat. This may in part be 
used again in the processes of repair, but a large proportion 
leaves the body as animal heat. 
As in the case of the corn, the stored energy (division C of 
the table), of the fat ox does not represent all of the energy 
expended in building up its organic substance. A constant 
process of repair has been going on to replace the waste 
resulting from the wear and tear of thesystem, which involves 
a continuous expenditure of energy—and the loss arising from 
the energy thrown off from the body as animal heat, (radia- 
tion), and expended in vaporizing the water exhaled from the 
skin, (perspiration), must be replaced at the expense of the 
stored energy of the food to keep the machinery of nutrition, 
in efficient activity. 
The facts presented are sufficient to show that the transfor- 
mations of energy are important factors in the economy of 
plants and animals, and that the materials of which they are 
composed cannot be looked upon as the sole subjects of interest 
in farm economy. The tendency to make the compounding 
of food rations the prominent subject for consideration, con- 
flicts with the interests of the breeders of improved stock, and 
misleads the farmers who are induced to look upon it as the 
real source of profit. This reference to the subject of feeding 
is made with the two-fold purpose of ealling attention to the 
fallacy of feeding experiments in which the chemical compo- 
sition of foods is made the prominent or sole object of interest, 
