254 
The Jipplications of Physiology 
land never take consumption. Mountain air is very much ex- 
panded, and consequently little oxygen enters the lungs at each 
resj)iration : hence it is all taken up by the blood, and does not 
act on the substance of the lungs."'' But D'Arboval, in continua- 
tion, informs us that those cottars who have no upland pastures, 
but keep their cattle shut up in miserable unventilated huts, lose 
many of them by this disease. This is another proof of our 
view. 
The exhalations from the cattle fill the hut, and enter into a 
state of decay ; or, to speak chemically, enter into union with the 
oxygen of the air. This decay or union is imparted to the lungs 
of the animals within its influence, and consumption results. 
And, in confirmation of this latter explanation, I refer you to 
Mr. Youattjj who states that, in crowded cow-houses, those ani- 
mals escape consumption which stand near the draughts of the 
doors and windows, and therefore have the deleterious exhalations 
carried off ; while those protected from the draughts often droop 
and die : | a jjriori, the very reverse would be expected. 
I said that diarrhoea also consisted of a union of oxygen with 
part of the intestines, and this disease generally accompanies con- 
* As a contrast to this I may mention a striking case which lately came 
under my own observation. In July last there were four days in which 
the barometer was unusually high (^i. e. the air very condensed) ; during 
those four days there were no less than five deaths of consumptive patients 
in the small town in which I reside. 
t Youatt on Cattle, p. 414. 
X Professor Sewell, in his ' Essay on the late Epidemic amongst Cattle,' 
has the following passage: — "However, a predisposition to receive the 
disease may, and I believe is, caused by the vitiated atmosphere in 
the stable or vicinity — arising from foul, damp, or unaired stables ; stag- 
nant cesspools, obstructed drains, or a want of drainage ; the vicinity of 
dung-pits or heaps ; stagnant water in ponds, ditches, and shallow streams 
which receive the contents of drains or of sewers ; irregular pavement, 
retaining the excrements, by which the floor is saturated." Now all these 
are cases io impart a pre-existhig decay, or union with oxyyeii, to some pari of 
the system. But all our experience of the diseases of cattle serves to sup- 
port this chemical explanation of tlieir origin. In cold weather, when tlie 
air is much condensed, and therefore when a large quantity of oxygen is 
ready to act upon the system, we find that acute inflammatory complaints 
are most common — i. e. complaints arisiny from an excess of oxyyen. On 
the other hand, when the temperature is elevated, and. therefore when the 
oxygen enters the system in less quantity, biliary complaints are most pre- 
valent. " Biliary diseases arise /rojn an excess of carbon," which the oxygen 
inspired does not suffice to consume (Liebig). In the Royal Veterinary 
College every precaution is taken to prevent the sick cattle from being 
exposed to an impure atmosphere. The consumptive patients are kept in 
sheds in the open air, in order that the decaying exhalations may be 
rapidly carried off, and none allowed to accumulate near them, lest 
their state of union with oxygen might be imparted to the system, and 
aggravate the malady. This, however, may be an explanation of their 
practice, which the professors of the College may not be willing to admit. 
