1901] MICROSCOPICAL J OURNAL.. : 81 
is possible, however, that the failure was due to errors in 
manipulation. We hope that some of our Southern read- 
ers, interested in microscopy, will experiment in this di- 
rection and let us hear from them on the subject.. 
A DIFFERENTIAL STAIN FOR BACILLI.—M. Gautrelet, 
searching for some method to stain the bacilli of tuber- 
cle so that the living microbes could be distinguished from 
the dead, and noting that in the urine of those suffering 
with hectic fever (tuberculous) the bacilli were so strong- 
ly colored by some urinary pigment that they could easi- 
ly be seen and recognized, concluded that the coloration 
was due to urobilin. He thereupon experimented with 
the agent, and succeeded in staining the bacilli of spu- 
tum with it without the application of heat. He: used 
the following formula: 
epee at FE AS aT NEM e a ea tbis . 1 part. 
Glycerin. . b obewidiene edt, BO ppae tei 
Distilled water. SCREEN ..20 parts. 
Alcohol. . Teta elon tg" ..30 parts. 
To use: Ro eand. rei shea on a agit Sela in the 
usual way, and place the latter, without drying or passing 
through the flame, directly into the soiution. At the end 
of an hour it may be removed, the superfluous liquid 
taken up by means of bibulous paper, and the clean side 
of the cover-glass wiped dry. The object is now ready 
for examination. The living bacilli will be found stain- 
ed a yellowish brown, and may be seen to continue their 
oscillatory movements. By means of examinations made 
by the aid of this process, M. Gautrelet was able to dem- 
onstrate that hydro-fluoric acid is a powerful anti-bacil- 
lary, capable of sterilizing tubercular cultures.—National 
Druggist. q 
MICROCHEMICAL REAGENT For TANNIN.—Lantz (Phar- 
maceutische Rundschau) states that ammonical copper sul- 
phate is an excellent microchemical reagent for tannin. It 
js, he declares, far more delicate than any reagent hith- 
