506 GOOD AND BAD POINTS OF CATTLE, AND 
I do not agree with the generally received opinion, nor with 
Dr. Lyon Playfair, that the lungs must be of necessity small 
when an animal first begins to fatten ; but, as the fattening pro- 
cess goes on, the internal cavity of the chest becomes smaller, 
the action of the heart weaker, and the lungs diminish in size in 
a regular gradation from various causes ; first, from limited ex- 
pansion ; secondly, from absorption, and by pressure of the sur- 
rounding parts ; and, lastly, from quietude never allowing their 
due inflation, which the act of depasturation affords. 
The liver is also found small. This I consider to be from 
absorption and internal pressure of the surrounding organs. The 
liver has also a diminished supply of intestinal and mesenteric 
blood, from the appetite not being so vigorous, and less food 
being eaten, as the animal grows to maturity. 
I have known many animals die from accident that, on inspec- 
tion after death, have had large lungs and livers. They were in 
lean condition, but had every good quality for fattening ; and I 
have no doubt would have made prime fat beasts, and whose lungs 
and livers, probably, would have been smaller when slaughtered. 
1 do think that Dr. Lyon Playfair is wrong in the opinion, 
that small lungs and livers are the best organs for the assimila- 
tion of food and fat. I think that the reason why animals be- 
come speedily fat in proportion as they approach maturity, is 
from the arterial action being slow, and the venous circulation 
impeded from the pressure of the accumulating fat. The arterial 
exhalents deposit more than the venous circulation can return, or 
their absorbents take up. Thus the harmony is broken. It is a 
fact well known, that very little blood of the venous kind can 
be taken from the fat animal. From what I have stated, taken 
collectively and in conjunction with the primeval external con- 
formation of the animal, may be deducted those determinations 
which tend to either the formation of fat or muscle. 
The tendency of certain articles of food to fatten stock, and 
the suitability of others to keep up the general growth, afford 
a fruitful field for inquiry. I shall begin with those that favour 
evolution of growth. A series of substances that are charged 
with albumen, or a vegetable gelatine, are nitrogenized in the 
maximum barley, oats, peas, and beans, form examples. These 
substances, having much nutritive matter, make the best food 
for the purpose of general growth, with the various herbivorous 
food for the young animal ; but the more such food approximates 
lignin, the more insoluble and innutritious it is. 
Herbivorous food for the young animal is naturally required, 
from its abounding with several elementary principles, as ammo- 
nia, &c., in unity with earthy matter; which, taken in with the 
