202 
M. NOCARD. 
The cow which served fur these preparations was destroyed 
for anatomical purposes. She was absolutely lean to an extreme, 
full of tubercles, even in the muscular masses—a curious condi¬ 
tion ; the udders were healthy, atrophied, but not tuberculous. I 
extracted a very small quantity of the milk, which was treated like 
the bronchial inuco-pus; numerous preparations were made of it, 
but no bacilli could be detected. This fact agrees with the experi¬ 
ment of Bollinger, which proved that the raw milk of phthisical 
cows did not transmit tuberculosis except in the case where the 
adders were the seat of tuberculous lesions. 
^ ^ ^ ^ ^ 
Since the 22d of May I have had occasion to see three phthys- 
ical cows. In one, the tuberculous masses were almost entirely 
calcified ; in all three I observed in the muco-pus of the bronchia 
the presence of a large quantity of bacilli; they were counted by 
hundreds under the held of the microscope. 
One of the cows used for the class of operative surgery 
seemed to me in the last stage of phthisis. She was a living 
skeleton, had repeated paroxysms of coughing, and ejected 
abundant mucosities; auscultation revealed a great roughness of 
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 prepared is placed in such 
a manner that the side on which the mucosity is shall be in contact with the col¬ 
oring matter. The duration of this contact is from 12 to 24 hours, if one oper¬ 
ates 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 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 aquous solution of bleu of methylene 
or of vesuvine': washed a last time with distilled 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 ele¬ 
ments of the preparation, cells, nuclei or microbes, having a blue or brown 
coloration. 
The glass can as well be mounted in the balsam as soon after the discoloration 
with the nitric acid; but then the bacilli only appear strongly colored in red, the 
remaining parts being colorless and nearly invisible. The double coloration gives 
the nicer preparation. 
