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Tuberculosis in Animals, and 
internal organs, but may be found in almost any part of the 
body when the infection has become general; thus, they may be 
found in the udders of cows in an advanced stage of the disease, 
sometimes in the lymphatic glands, beneath the lower jaw, and 
about the throat ; more rarely in the interior of the bones, and 
still more rarely in the muscular tissue, or flesh. In the advanced 
stages of tuberculosis there is little difficulty in determining its 
existence, but in the early stages, when the deposit is limited 
in extent and confined to the lungs only, the diagnosis becomes 
extremely difficult, and the expert has to hesitate, because he 
knows that other morbid changes and products closely resemble 
tubercle and can only be distinguished from it by microscopic 
examination. 
From the above it will be seen that, looking at tuberculosis 
from this practical and every-day aspect, there is often great 
difficulty in recognising its existence in the living animal, or 
even determining by the unaided eye its presence in the tissues 
or organs after death. In dealing with tuberculosis as a disease 
of animals, or with the question of the fitness or unfitness of the 
flesh or milk of tuberculous animals for human food, the practical 
view must always come first, and the experimental or bacterio- 
logical view follow as a means of confirming or correcting the 
evidence obtained from symptoms during life and appearances 
after death. 
In reference to the pathological study of tuberculosis, the 
same may be said as about its history, that it has no well defined 
starting point. The experimental and bacteriological investi- 
gations date back only comparatively few years. In 1843 
Klencke came to the conclusion that tuberculosis was due to a 
specific virus, was, in fact, a contagious disease ; but it was not 
until 18G5, when Yillemin published the results of experiments 
which showed that this disease could be transmitted from man 
to animals by inoculation, that this view of its nature began to 
be generally adopted. Gerlach conducted a series of experiments, 
1866-69, and confirmed the results of Villemin's previous 
investigation. These and other confirmatory experiments clearly 
demonstrated that the disease was an inoculable one. In 1869 
Chauveau began a series of observations, with the object of 
ascertaining whether tuberculosis could be induced by feeding 
animals with tuberculous material, and also, if it was possible 
to produce the disease in animals by the inhalation of the dried 
and finely pulverised sputum of consumptive patients. From 
these experiments, which were of a very comprehensive nature, 
Chauveau came to the conclusions that the disease could readily 
be contracted by both ingestion and inhalation. M. St. Cyr, 
