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 : 



Starch, oil, and 1 } partly ( Fatty and \ but chiefly f Carbonic acid and water, 

 other non-azo- > converted < other animal [thrown off< disengaged hy the respi- 

 tized compounds J 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 

 created 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 hydrogea 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 



