156 NUTRITION OF HERBIVORA AND OF MAN. 
destination of this part of their food ; that of the albuminous — 
matters, here much smaller in amount, being the same as in 
the preceding case :— 
other non-azo-}converted ; other animal 
Starch, oil, and) partly Fatty and _) but chiefly ( Carbonic acid and water, 
{ thrown off 
tized compounds into tissues, 
directly as \ ratory process. 
The proportion of the food deposited as fat, will depend in 
part upon the surplus which remains, after the necessary sup- 
ply of materials has been afforded to the respiratory process. 
Hence, the same quantity of food being taken, the quantity 
of fat will be increased by causes that check the perspiration, 
and otherwise prevent the temperature of the body from being 
lowered, so that there is need of less combustion within the 
body to keep up its heat. This is consistent with the teach- 
ings of experience respecting the fattening of cattle ; for it is 
well known that this may be accomplished much sooner, if 
the animals are shut up in a warm dwelling and are covered 
with cloths, than if they are freely exposed in the open air. 
163. Now the condition of Man may be regarded as inter- 
mediate between these two extremes. The construction of 
his digestive apparatus, as well as his own instinctive pro- 
pensities, point to a mixed diet as that which is best suited 
to his wants. It does not appear that a diet composed of 
ordinary vegetables only, is favourable to the full develop- 
ment of either his bodily or his mental powers ; but this 
cannot be said in regard to a diet of which the corn-grains 
furnish the chief ingredient, since the gluten they contain 
appears to be as well adapted for the nutrition of the animal 
tissues, as is the flesh of animals. On the other hand, a diet 
composed of animal flesh alone is the least economical that 
can be conceived ; for, since the greatest demand for food is 
ereated in him (taking a man of average habits in regard to 
activity and to the climate under which he lives) by the ne- 
cessity for a supply of carbon and hydrogen to support his 
respiration, this want may. be most advantageously fulfilled 
by the employment of a certain quantity of non-azotized food, 
in which these ingredients predominate. Thus it has been 
calculated that, since fifteen pounds of flesh contain no more 
carbon than four pounds of starch, a savage with one animal 
and an equal weight of starch, could support life for the same 
length of time during which another restricted to animal 
disengaged by the respi- — 
