670 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Fig. 174. 
hopper holds 2-3 litres, has very sloping sides, and a pipe with two 
stopcocks (fig. 174). The bore of the pipe is 0*6 cm. wide, and the 
lumen of the tapways is the same. The space between the taps is con- 
nected with a pipe edc , the bore of which is 0*3-0 *4 cm. in diameter. 
This pipe is supported at d by an attach- 
ment to the stand, and its free end is con- 
nected with a piece of rubber tube closed 
by a Mohr’s pinch-cock with Leiss’s hook. 
The taps are all closed when the water 
is poured in. When the sediment has 
collected at the lower end of the hopper, 
the tap a is opened. The sediment-water, 
however, does not pass into the pipe until 
the pinch-cock is nipped. The tap a is 
then closed, and the contents are allowed 
to escape into a porcelain dish by opening 
the tap b. 
The illustration shows the chief mea- 
surements. 
Bacteriological Diagnosis of Plague.* 
— Dr. C. B. Stewart describes the methods 
adopted at the Bombay Research Labora- 
tory for diagnosing the plague in man or 
animals, and for testing a plague culture. 
The remarks apply only to recent cultures 
on agar or in bouillon at the ordinary 
room temperature, the optimum being 74° 
F. The colonies on agar appear in 24 to 
48 hours, and, when touched with a wire, 
slip about on the surface. After one or 
two days’ incubation, agar slants which have been smeared with 0 * 1- 
0 * 2 ccm. of broth culture show the “ ground-glass ” appearance when 
inspected from underneath. 
In broth the stalactitic growth is held to be characteristic of the 
plague microbe.! It has been found that the addition of a little cocoa- 
nut oil or of glue, before sterilisation, facilitates the formation of stalac- 
tites by affording points d’appui. Another phenomenon which appears 
to be characteristic consists in growth along and up the glass rod which 
has been used for inoculating the flask. When the upward growth 
reaches the surface, it spreads out, covering the surface with colonies, 
from which stalactitic downgrowths soon depend. The broth remains 
quite clear. 
The microbe stains readily with anilin dyes, but not by Gram’s 
method. The bipolar staining is not constant, but bipolar spots are 
easily detected in living and unstained specimens. Suspensions of 
plague microbes in water dry as a bluish film on a slide. The microbe 
is polymorphic ; sometimes it resembles a coccus or diplococcus ; some- 
times a short stumpy bacillus, with rounded ends ; diplobacilli are 
frequent, and sometimes there are short chains. 
* Bril. Med. Journ., 1899, ii. pp. 807-8. f Cf. this Journal, 1897, p. 327. 
