400 
A. LIAtJTARD. 
confirmed the correctness of the diagnosis, the bacillus being- 
present in the lesions found at the post mortem investigation. 
The same diagnosis made upon another animal was proved to 
have been erroneous by the absence of the bacilli of Koch from 
the sputa, and the corresponding absence of true tuberculous 
lesions, as proved by the autopsy. As many of us in this assem¬ 
bly may not have the article referred to, I beg to describe briefly 
the manipulations required by which the bacillus of tuberculosis 
can be rendered evident in any specimen in which it exists in 
nature. 
The solution of Erlich, which is used, is made by shaking 
firmly 100 grammes of distilled water and 40 grammes of oil of 
aniline, with a saturated aqueous solution of oil of aniline, and 
filtering the whole. Of this, take 100 grammes, with 1 cubic 
centimetre of a saturated alcoholic solution of fuschine. 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 the albumen. 
A few drops of the solution of Erlich is then poured into a 
watch-glass, and over the surface of this liquid the glass thus pre¬ 
pared is placed in such a manner that the side on which the 
mucosity is shall be in contact with the coloring matter. The 
duration of this contact is from 12 to 24 hours, if one operates 
under the ordinary temperature; or it may be reduced to 15 or 
20 minutes, if the watch-glass is placed over an alcoholic lamp 
and left until a slight vapor begins to show itself on the surface 
of the liquid. 
The colored glass is then washed with distilled water, dipped 
into a solution of nitric acid to the third, just the time necessary 
for all coloration to disappear. This time varies, according to the 
thickness of the mucosity dried on the glass, from ten seconds to 
a minute. The glass is again washed with distilled water, then 
put for a few minutes into a concentrated aqueous solution of 
blue of methylene or of vesuvine: washed a last time with dis¬ 
tilled water, then dried; the glass, which had taken a handsome 
blue or marine color, is mounted with Canadian balsam. The 
bacilli of Koch appear strongly colored in red; all the other 
