RESEARCH FOR THE BACILLUS OF KOCH. 
261 
it in twelve eases of phthisis pulmonalis examined by himself. 
The caseous centres contained them in quantity. But what is 
more important, in the point of view of diagnosis, is that the 
bacillus exists also in the products of expectoration, with all the 
specific characters indicated for that of human tuberculosis, and 
that the same manipulations are sufficient to render them evi¬ 
dent. In doubtful cases, then, and these form the majority in 
the bovines, the veterinarian can, like the physician, establish the 
diagnosis with certainty, after examination of the bronchial nin- 
cosities of the animal under suspicion. 
The phrase, “ like the physician ,” may convey an - exagger¬ 
ated sense, for it is easy for him to obtain his patient’s sputa for 
examination, while it is not so for the veterinary surgeon, for the 
ox does not expectorate. The purulent mncosities thrown off 
from the bronchial passages by the act of coughing, are swal¬ 
lowed (and to this, may it not be said in passing, is doubtless to 
be attributed the frequency and serious character of the tuber¬ 
culous lesions of the mesenteric glands of bovines.) It is only 
exceptionally that in a violent act of coughing mueo-pus is ex¬ 
pectorated externally. But the difficulty can be obviated. By 
pulling the tongue outside of the mouth, deglutition is prevented, 
and if the animal is made to cough, the purulent mncosities ex¬ 
pelled fall on the floor and can be easily secured for examination. 
Of course, we know how difficult it is to make a healthy cow 
cough, but it is not so with a sick one. 
Here are preparations of bronchial mucosities obtained from 
a tuberculous cow* and treated by the Erlich method ; you can 
observe the presence of considerable numbers of very small 
bacilli strongly colored in red, while the bottom of the prepara¬ 
tion is either colorless or colored in bine or in brown, (blue of 
methylene or vesuvine). 
* The best technical manner to follow, both the simplest and the most rapid, 
is that indicated by Erlich, one of Koch’s students. With a saturated 
aqueous solution of oil of aniline, shake firmly 100 grains of distilled water, 
with 40 grains of oil of aniline, and filter. Of this take 100 grains, and of 
saturated alcoholic solution of fuschine, 1 cub. centim. : a shade of mucosity is 
spread in a thin layer between two glasses ; each of these is then rapidly passed 
two or three times through the flame of an alcoholic lamp, to dry and coagulate 
