to the Rearing and Feeding of Cattle. 
253 
animal stall-fed. I tlien fed the animal upon various kinds of 
food, such as hay, potatoes, oatmeal, beans, &c., mixings these in 
determinate weights, and analysed the milk of the cow fed upon 
such food. 
The details of the experiments are too numerous to bring 
before you on the present occasion, and I shall therefore publish 
them in a separate paper. I may merely state at present that the 
difference in composition was most marked, and fully bore out 
the manner of estimating the value of food, as given in the pre- 
ceding tables. Beans were found to increase the quantity of 
cheese in the milk, as theory would lead us to expect, while 
steamed potatoes caused an abundant increase of the butter. 
IV. Before concluding the subject of feeding cattle, might I be 
permitted to say a few words with reference to certain of their 
diseases, though this does not come within the subject assigned to 
me by the Council of the Society. When we consider the most 
important diseases of sheep, such as rot, foot-rot, black-water, con- 
sumption, diarrhoea, and dysentery, we find that they possess, in 
a chemical point of view, a generic character. They are diseases 
which effect a transformation or decay of particular parts of the 
body. 
When a fresh orange is placed upon a decayed one, the decay 
in the latter is communicated to the former, and the fresh orange 
becomes tainted. In like manner a piece of decaj ed wood occa- 
sions the decay of a piece of sound wood placed in its vicinity. 
There are numerous chemical instances of the same fact;* and 
indeed it appears to be a law pretty well established, that every 
body in a state of change has a disposition to throw any other body 
with which it comes in contact into the same state with itself. 
Now (we speak only in a chemical point of view) consumption, 
diarrhoea, and dysentery may be classed together, as being in the 
same category of diseases. The first is an inflammation of the 
lungs ; the two last, of the intestines. Inflammation, in a chemical 
sense, is the proper term ; for the true definition of the term is, a 
combustion, or union with the oxygen of a part of the tissues, or 
of the secretions of those tissues. That the final cause of con- 
sumption merely consists in an oxygenation or combustion of the 
substance of the lungs, instead of the blood circulating within 
them, is proved by many circumstances. First, in consumption, 
the lungs disappear or are consumed, along with other parts of 
the body, which participate in the combustion. Thus the milk 
of a consumptive cow contains very little butter. D'Arbovalj 
assures us that the cows fed on the mountain pastures of Switzer- 
* See the 2nd Part of Liebig's Agricultural Chemistry. 
•]• Youatt on Cattle, p. 413. 
