526 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
standing the presence of cholera bacillus the nitroso-indol reaction may 
fail if microbes capable of reducing nitrates be present in the stools. 
Cultivating Influenza Bacillus.* * * § — Dr. Huber, who has examined 
twenty cases, recommends blood-agar in preference to hsematogen-agar, 
as the bacilli grow less vigorously on the latter, and also because 
puncture cultivations are possible with it. The chief property of 
haemoglobin which renders it valuable for cultivating the influenza 
colonies is that it contains iron, and not because it is a carrier of oxygen. 
The bacillus can also be cultivated on haematogen-bouillon, while the 
presence of caustic soda was found to be unsuitable. 
Growing and Examining Bacterium Zopfii.f — In their experiments 
Drs. R. Boyce and A. E. Evans employed 10 per cent, gelatin with 
neutral or faintly alkaline reaction, though there was no appreciable 
difference in the growth when the reaction was slightly acid. The 
method of cultivation consists in placing a small piece of moist cotton- 
wool in the bottom of a test-tube large enough to hold the ordinary 1 by 
3 in. slide. The test-tube is plugged and the whole steam-sterilized at 
120° for 20 minutes. When cool, a thin uniform layer of sterilized 
gelatin is spread over the slide, kept in horizontal position, by means of 
the Pasteur balloon pipette. The test-tube is then plugged and capped 
to prevent drying. When a streak culture has been made and it is 
desired to examine the growth, the slide is removed and placed in 
slightly diluted spirit for a few hours to fix the growth and extract the 
salts. The slide is then carefully dried, stained by Gram’s method, and 
mounted in balsam. 
Ordinary test-tube growths may be examined microscopically in situ 
by just warming the test-tube sufficiently to set the gelatin free, and 
then sliding it off on to a glass plate. A cover-glass is then put on and 
the growth examined. The best temperature was found to be about 
21° C., which in 24 hours gave a perfect growth ; this might be hastened 
if the back of the gelatin were painted black. 
Cultivating Cholera on Eggs.J — Herr Zenthofer finds that when 
pure cultivations of cholera bacilli are grown on eggs there is no 
evidence of the development of H 2 S, the yolk preserving its normal 
honey-like colour, while the white becomes cloudy and liquefied. When 
H 2 S was demonstrable in any quantity its presence was found to be due 
to the impurity of the cultivation, the other bacteria predominating over 
the cholera bacilli. The eggs used were purified by leaving them for 
more than an hour in a 1-1000 solution of sublimate, a procedure which 
possibly exerted some slight inhibitory effect on the growth. Some of 
the cultures were anaerobic, and were grown in an atmosphere of 
hydrogen. 
Plate Diagnosis of Cholera.§ — Dr. Eisner adds to 1 litre water 
250 grm. gelatin, 10 grm. Liebig’s extract, 10 grm. pepton, and 5 grm. 
* Zeitschr. f. Hygiene u. Infektionskr., xv. (1893) pp. 951-9. See Centralbl. f. 
Bakteriol. u. Parasitenk., xv. (1894) p. 439. 
f Proc. Roy. Soc., liv. (1894) pp. 300-12 (2 pis.). 
j Zeitschr. f. Hygiene u. Infektionskr., xvi. pp. 362-7. See Centralbl. f. Bak- 
teriol. u. Parasitenk., xv. (1894) p. 752. 
§ Hygienische Rundschau, 1894, No. 7. See Centralbl. f. Bakteriol. u. Para- 
siteuk., xv. (1894) p. 877. 
