648 
LECTURE ON THE DISEASES OF CATTLE. 
liminary question, however, to be dealt with, before we can arrive 
at any sound conclusion : viz. What do we really mean by health ] 
This may seem a very simple question to put, but it is really one 
of the most difficult questions to answer. Many will say, perhaps, 
“ We know that our animals are in health when they are thrifty.” 
But, in truth, animals may be thrifty with a mass of disease in 
their lungs or their livers. The condition of the disease may not 
be such as to prevent them from thriving. To say that an animal 
is healthy, and to say that it is healthy because it is thriving, are 
two very different things. 
It is one of the wise provisions of nature that every function of 
the body has the power of correcting or assisting other functions. 
Thus we find that when the lungs cannot throw off the due pro- 
portion of carbonic acid, the liver will assist them in doing so. 
This we see exemplified in the case of those who are suffering 
under consumption ; they almost always have diarrhoea arising 
from the derangement of the liver, and this arises from the effort 
made to get off that which they cannot get rid of through the 
lungs. Thus, with regard to lambs which have the black scour, 
if you watch them you will find that they do not inhale the proper 
volume of air ; you see it also occasionally in cattle, though it is 
not so prevalent in those animals, because not so easily excited ; 
they are not so frequently put into a state in which the lungs are 
apt to become diseased. You find it occasionally amongst ewes 
which are suffering from the results of difficult parturition. It is 
very frequent amongst swine under that form which is commonly 
called murrain. I am greatly disposed to believe that murrain 
generally results from the confinement of animals in impure styes, 
or damp muck-yards. 
I need not say that the perspiration, bile, urine, saliva, and 
respiration are some of the principal functions of the body. Now, 
as long as these are in a state of equilibrium one with the other, 
nature possesses the power of resisting disease; but, supposing 
anything should arise by which a single function becomes either 
suspended or excited in too great a degree, the effect is to destroy 
the equilibrium, and in proportion as that is more or less deranged 
will there be danger to the animal’s life. Of course, therefore, the 
earlier we can deal with the disease after the disturbance of the 
equilibrium the better will be our chance of restoring it. If an 
animal be exposed to a cold, north-easterly wind, it would be 
chilled, and probably the cold will be accompanied with an attack 
of fever, unless proper precautions are taken. If, after exposure 
to cold, the animal be taken into a warm place, and bran or chaff 
be given to it, probably by the next day it will entirely recover ; 
otherwise the illness will progress from simple cold to fever, and 
