ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
457 
value, it was found tliat the action of cholera serum upon more or less 
closely related vibrios might be complete or nil. All the typhoid bacilli 
reacted to typhoid scrum, but none to that of B. coli , so that, given a 
young culture and typhoid serum, a diagnosis can be made in a few 
minutes. 
Formation of Gallstones by Bacteria. * — MM. A. Gilbert and L. 
Fournier examined 36 cases of gallstones, 3 of which were from cattle. In 
14 cases bacteria were found, and in 11 instances were cultivated. The 
organism isolated was B. coli commune. In order to determine whether 
B. coli penetrates into the calculus after its formation, the following 
experiment was made : — A. pretty large cholesterin stone was incubated 
for 1 hour at 75° daily for 3 weeks. It was then put in a tube inoculated 
with B. coli, and incubated at 33° for 14 days. In its interior, when 
examined, B. coli was found. A similar experiment with a pigment 
stone gave negative results. From this the authors infer that in the 
majority of cases the introduction of bacteria into gallstones is not sub- 
sequent to their formation, as it is rare for a gallstone to be composed 
entirely of pigment, and then they are small and gravelly. Most gall- 
stones are mixtures of cholesterin and pigment. 
Nitrifi cation in the SoiL| — Herren R. Burri and A. Stutzer found, 
in all cultures in which ammonia salt was oxidised to nitrite, a coccoid 
organism closely resembling Nitromonas europsea described by Wino- 
gradsky. Both organisms form zooglcea-like masses in mineral nutrient 
solutions. But, while Winogradsky’s organism exhibited movements at 
times, that of the authors was always immobile. No success attended 
the attempts to obtain pure cultivations of a nitrite-forming organism on 
silicic acid plates. As far as could be judged from comparative experi- 
ments, conducted j with impure cultivations in mineral solutions, as to the 
oxidising power of nitrite-formers of different origin, there was no 
particular difference in the efficacy of those examined, five of which 
came from Germany and one from Africa. A nitrate-forming organism 
was isolated from a sample of earth from Northeim, and this the authors 
hold to be identical with that cultivated by Winogradsky from Quito 
earth. This organism throve on organic media, such as gelatin, but then 
did not oxidise any nitrite, and on reinoculation on mineral media often 
appeared to have lost its oxidising power, for only in a few instances 
could nitrate production be obtained. Experiments made with no t 
perfectly pure cultures of nitrate-formers of German origin did not 
betray any important differences. Cultures which contained both nitrite 
and nitrate-formers, provided there were present in the medium a salt 
containing nitrogen, showed that nitrification was effected in the same 
way as in the soil — i. e. the ammonia salts were apparently transformed 
directly into nitrates without any demonstrable nitrite formation. 
Fermentation of Uric Acid by Microbes4 — M. E. Gerard has 
shown that uric acid can be decomposed by microbes into urea and car- 
bonate of ammonia. Further experiments were made to estimate the 
* La Semaine Med., 1896, No. 8. See Centralbl. f. Bakteriol. u. Parasitenk., 
l ,e Abt., xix. (1896) pp. 629-30. 
f Centralbl. f. Bakteriol. u. Parasitenk., 2 te Abt., ii. (1896) pp. 105-16, 196-204: 
(1 pi.). % Comptes Rendus, cxxii. (1896) pp. 1019-22. 
