568 
GANGRENOUS CORYZA IN THE OX. 
had, in some cases, the consistence of a clear yellow pus. Thus, 
as 1 have before said, the lucid cornea had completely lost its 
transparency. 
The causes of this cruel malady cannot be precisely determined. 
It makes its appearance both on high and low ground. Coryza, in 
other animals, usually appears during the autumn or winter. In 
horned cattle it shews itself in all seasons, and, if it is more fre- 
quent at one time than another it is in the summer, a season at 
which it is seldom found to attack horses, sheep, or even men. It 
now attacks animals of all ages without distinction. Nevertheless, 
1 have seen it oftener in young than in old animals. Are they 
more subject to inflammatory diseases 1 or may not this be occa- 
sioned by there being more young animals than old ones exposed 
to it ? This appears to me to be most probable ; for it is not un- 
usual to see in one stable twice as many animals under five years 
old as there are over. I have always observed that strong and 
vigorous animals are much more exposed to it than those that are 
weakly and ailing. I have discovered one predisposing cause, 
which is the formation of the head, — it is then fat, covered by a 
thick and ragged skin, and then the eyes are habitually moist or 
inflamed, the muzzle thick, and the nostrils close, allowing only a 
straight passage to the air, and, consequently, rendering the respi- 
ration difficult and impeded. 
Every cause which determinates inflammatory disorders may 
cause coryza, which quickly acquires a gangrenous character. In 
this number ought to be reckoned sudden changes from a hot to a 
told temperature, and the showers in which animals are frequently 
caught while at work or at pasture ; but I believe the most fre- 
quent of these causes is the ammoniacal gas which these animals 
breathe, more particularly during the summer, and in badly ar- 
ranged stables. This air irritates the nasal membrane for some 
time, and ends by determining a phlegmasy, which leads on to 
gangrene, like many other diseases of oxen. In horned cattle we 
can cite many facts in confirmation of these circumstances. The 
gangrenous termination of inflammation is much more frequent in 
them than in any other animals. It is not, then, surprising that, 
in the case of which we are speaking, coryza, which is terminated 
by resolution in other animals, becomes gangrenous in the ox. 
In support of what I have said on the effects of ammoniacal 
gas, I must add, that I have remarked that the disease is not so 
frequent in clean and well-ventilated farms and stables as it is in 
those which are dirty, and where there is no free current of air. 
Lastly, exposure to the sun appears to be one of the causes of 
gangrenous nasal catarrh. 1 have seen animals whose ovvners had 
