420 CHEMISTRY IN AGRICULTURE AND PHYSIOLOGY. 
equivalent to a waste of food.” The capacity of the chest 
in an animal is a constant quantity, but the quantity of oxygen 
inspired is affected by the temperature of the atmosphere ; 
air is expanded by heat, and contracted by cold, and there¬ 
fore, equal volumes of hot and cold air contain unequal 
weights of oxygen : hence, the instant we leave a warm room 
for the cold open air, an infinite wisdom has so arranged, 
that the amount of oxygen in the atmosphere is always 
exactly that required to support the body at its natural tem¬ 
perature. 
The rapidity with which the structures of the body are 
reproduced, will depend on the amount of exertion to which 
they are subjected, and the quality of matter with which 
they are supplied. Place an animal in a position where the 
least possible amount of motion is given, and supply him 
liberally with food, the process of nutrition is then carried on 
with extreme rapidity, and a call is made upon the various 
excreting organs to remove this large amount of matter from 
the system. 
From inordinate exertion, these become deranged and 
unable to perform their office; the animal organism has then 
another source by which to relieve itself; namely, by deposit¬ 
ing large quantities of those matters which in the normal 
condition of the animal would be appropriated to the build¬ 
ing up of his tissues, in various parts of his body, in the 
form of fat. 
This action, when once set up, has a tendency to progress 
with great rapidity, and in proportion as this increases, the 
other tissues, muscle, &c., decrease. The muscles waste, and 
an animal in this condition (fat, although he may appear to 
be in the highest possible state of health), is in reality in a 
state of extreme debility. 
Remove an animal from this position, and subject him to 
exertion, gradually increasing it, as you find it can be borne, 
and what do you observe ? This fat is rapidly removed, and 
excreted from the system by the process of respiration. By 
keeping him in this position, nicely apportioning the quan¬ 
tity of food to the amount and severity of the exertion he 
undergoes, we may bring him into a state of the highest 
physical power. 
(To he continued .) 
