An Essay on Fat and Muscle. 
253 
it is found that calves get fat in a considerably shorter period than 
if allowed to move freely about in an open stall. 
Example No. 3. — Again, in the suckling of house-lambs of the 
early Dorsetshire breed for the London markets, the dams are fed 
with hay, oil- cake, and cal)bage in an enclosure adjoining the 
apartments where the lambs are co.ifined. The lambs are ex- 
cluded from the light, except at the intervals when the shepherd 
suckles them uj)on the ewes. Some feeders confine their lambs 
in narrow separate stalls to prevent them from playing with one 
another, but others deem the exclusicm of light and the absence 
of motion and noise sufficient for this purpose. By these means, 
they speedily fatten, and their flesh becomes exceedingly white 
and delicate. 
1 1 . 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 speedilv become fat. By reference to the 
table containing the relative proportions of nutritious matter in 
the ordinary cultivated crops of the farmer (5), it will be seen 
that the proportion of beef-suet which exists in wheat or barley, 
straw and turnips, is exceedingly small ; indeed the turnip does 
not contain any ; and yet animals under such a diet will speedilv 
fatten. The fat then is the product of a peculiar digestive pro- 
cess on the unazotised 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, II 10, O 10, we take 9 at oxygen, there remains 
C 12, H 10, O, 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 abnormal condition, since wild animals, such as 
the hare, the roe, and the deer, never produce any — the exercise 
which they continually undergo preventing its formation ; beildes, 
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 organised tissue all the nutritious parts of 
their food beyond the quantity required for supplying the res- 
piratory process and the waste of the system ; so that they soon 
become plump and floshv. 
12. Want of exercise then and diminished cooling are equiva- 
lent 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 
