ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
115 
New Biological Test for Cholera Bacteria.* — Herr O. Bujwid 
finds that iodoform exerts considerable influence on the growth of cholera 
bacilli, and little or none on that of bacteria resembling cholera vibrios. 
If cholera bacilli be mixed with gelatin and placed in a test-tube, and 
then exposed to the vapour of iodoform the gelatin will remain 
unliquefied for 10 to 15 days, while in control tubes the superficial 
layers begin to be liquefied on the second day. 
It is noteworthy that the quantity of iodoform in the vapour is so 
small, that even after 18 days no diminution in weight can be detected 
by most sensitive scales. 
In 10 to 15 days liquefaction begins and proceeds, the iodoform 
notwithstanding. No like effect was produced by the following sub- 
stances : — Camphor, naphthalin, hypochlorite of calcium, turpentine, 
thymol, phenol. Iodine has some, but much weaker, effect. 
On the choleroid bacteria, e. g. B. Finkler-Prior , Vibrio MetscJmikovi , 
B. Miller i, B. Benecki, the effect is much weaker, and liquefaction is 
perceptible on the third day. The difference is little dependent on 
external conditions, and holds good for low and high temperatures, 
even for such at which the gelatin begins to liquefy ; for the liquefied 
gelatin remained quite clear under the iodoform action, while the 
control gelatin is quite cloudy. 
Old and new cultivations give the same reaction, and the author 
thinks that the action of iodoform should be added to the methods for 
distinguishing cholera bacilli from other bacteria, and that this might be 
known as the iodoform test. 
Bacteriological Diagnosis of Cholera. t — According to Dr. Pfeiffer 
the only certain procedure for diagnosing cholera is by cultivating on 
the gelatin plate. Colonies of cholera bacilli can be certainly recog- 
nized in 24-36 hours, and more especially if the cultivations be made 
with dejecta in which liquefying bacteria are rare. 
Bujwid’s reaction with mineral acids is regarded as very uncertain 
and the presence of comma bacilli in microscopical preparations from 
suspected material should only be regarded as presumptive evidence. 
On the other hand, the method of Schottelius may be adopted in many 
cases, though if there be time it should be controlled by the plate 
method. Schottelius’ method consists in mixing the material to be 
examined with a thick layer of bouillon, and as the cholera bacilli are 
strongly aerobic they grow on the surface, forming a delicate scum 
which is almost a pure cultivation. 
Cop lin, W. M. L., and D. Be van — A Test Reaction for the Culture of the 
Micrococcus pyogenes aureus. Med. Record , II. (1892) p. 70. 
Dei Sant i. L. — Note sur la sterilisation de l’eau par precipitation. (Note on 
the Sterilization of Water by Precipitation.) 
Compt. Rend. Soc. Biol., 1892, pp. 711-3. 
M erke, H. — Ein Apparat zur Herstellung keimfreien Wassers fur chirurgische 
und bakteriologische Zwecke. (Apparatus for producing Germ-free Water for 
Surgical and Bacteriological Purposes.) Berl. Klin. Wochenschr., 1892, pp. 663-5. 
* Centralbl. f. Bakteriol. u. Parasitenk., xii. (1892) pp. 595-6. 
f Deutsch. Med. Wochenschr., 1892, No. 36. See Centralbl. f. Bakteriol. u. 
Parasitenk., xii. (1892) pp. 483-4. 
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