262 
Tlie Ap2^licatio)i s of Physiology 
would remain untransformed in the form of flesh. The nitro- 
genized substances of the bile are unfit for the nutrition of the 
animal, and are consequently separated from the blood by the 
kidneys. From this it is obvious that an animal with a small 
liver will -increase more rapidly in flesh as well as in tallow^ be- 
cause less of the nitrogenous part of its food is required for the 
formation of the bile. 
All this is not fanciful doctrine, as you may at first suppose. 
Thus I told you in my last lecture, that we could not fatten a goose 
when salt was given to it in quantity sufficient to form bile, 
although not to purge. This goose was crammed several times a 
day, and yet it did not fatten, because most of the food was 
formed into bile and passed out with the excrements. 
You may have heard that Mr. Bakewell used to bring his sheep 
to the market some time before other feeders. This he effected 
by producing rot. In the early stages of rot sheep accjuire both 
fat and flesh with wonderful rapidity.* This probably arises 
from the liver being unable to produce the proper quantity of bile. 
In certain diseases arising from inflammation of the liver, both 
this organ and the blood become loaded with fat. The food, 
which otherwise would have formed bile, now produces fat and 
flesh. In making any observations on this point to ascertain 
whether or not my opinion be correct, you must always discrimi- 
nate between sound livers and those which become enlarged by 
disease or by the insertion of fat between its cells. 
From the remarks which I have now ventured to make, you 
will perceive that I consider the aptitude of an animal to fatten 
to be due to the size of its lungs and of its liver. Of course the 
size and proper play of the heart must also have great influence, 
but this in a less direct way, and more from the general consti- 
tution of the animal being determined by it. The size of the 
intestines will also be proportional to the magnitude of the other 
organs. 
There arc certain external signs which enable us to determine 
whether or not an animal possesses an aptitude to fatten. 
Amongst these, smallness of the bones seems to be one of the 
most generally recognised. 
Smallness of bone is generally the indication of delicacy of 
constitution. An animal with large bones to support the weight 
of its body is active, like the Irish pig, and apt to become restless 
in its habits. Activity and lethargy have much connexion with 
the quantity of oxygen taken into the system. The inhabitants of 
cold countries are very active and fond of laborious employment ; 
those of warm countries are, on the contrary, lethargic. In the 
* Youalt on Sheep, p. 44G. 
