G03 
AN ESSAY ON FAT AND MUSCLE. 
separate stalls to prevent them from playing with one another ; 
but others deem the exclusion of light and the absence of motion 
and noise the best for this purpose. By these means they 
speedily fatten, and their flesh becomes exceedingly white and 
delicate. 
This brings us to that very important part of our Essay, the 
Production of Fat. We have seen, from the examples just 
adduced, that, under certain circumstances, viz., the absence of 
exercise and cold, and the presence of a proper supply of food, 
herbivorous animals speedily become fat. By reference to the 
table containing the relative proportions of nutritious matter in the 
ordinary cultivated crops of the farmer, it will be seen that the 
proportion of beef-suet which exists in wheat or barley or straw and 
turnips, is exceedingly small; indeed, the turnip does not contain 
any, and yet animals under such a diet will speedily fatten. The 
fat, then, is the product of a peculiar digestive process on the un- 
azotised constituents of the food, and is formed in consequence of 
a want of due proportion between the food taken into the stomach 
and the oxygen absorbed by the skin and lungs. The chief 
source of fat is starch and sugar, and its composition is such, that 
if deprived of oxygen, fat remains. “Thus, if from starch C 12, 
H 10, O 10, we take 9 at oxygen, there remains C 12, H 10, O 1, 
which is one of the empirical formulae for fat.” It is obvious from 
this that Liebig’s theory is the right one, and that fat can only be 
formed by a process of deoxidation. He regards fat as an ab- 
normal condition, since wild animals, such as the hare, the roe, 
and the deer, never produce any — the exercise which they con- 
tinually undergo preventing its formation. Besides this, they never 
eat except when hunger requires it, while the sheep and the ox 
eat almost without intermission, and, when young, they convert 
into fat and organized tissue all the nutritious parts of their food 
beyond the quantity required for supplying the respiratory process 
and the waste of the system; so that they soon become plump 
and fleshy. 
Want of exercise, then, and diminished cooling are equivalent 
to a deficient supply of oxygen, for when these circumstances 
occur, the animal absorbs much less oxygen than is required to 
convert into carbonic acid the carbon of the substances destined 
for that purpose. We have a beautiful example of this in the 
“ conditioning of the hunter,” which consists in giving such exer- 
cise and food as will, without reducing the strength of the animal, 
prevent the formation of superfluous flesh and fat. Air , exercise , 
and a proper supply of nitrogenised food, such as oats, peas, beans, 
&c., contain the grand secret in the art of training. But these 
articles also contain a large proportion of starch and fatty matters, 
