ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 
771 
tlie power of forming H 2 S, and of these, some, e. g. bacillus of rabbit 
septicaemia, B. fulvus, and B. subtilis are essentially aerobic, a fact 
worthy of notice, inasmuch as the formation of H 2 S is usually regarded 
as a reduction process taking place in the absence of oxygen. 
By the author’s experiments, which showed that different germs culti- 
vated in the same medium, behaved differently with regard to the forma- 
tion of H 2 S, the question whether the protoplasm of bacteria was endowed 
with different powers of forming H 2 S, was answered in the affirmative. 
Experiments made with H 2 S formers, e. g. Proteus vulgaris and 
bacillus of rabbit septicaemia, and with two non-formers, e. g. Tetra- 
genus and Wurzel-bacillus, showed that the former, when cultivated on 
quite different media, always formed H 2 S, while the latter did not. 
And even when the sulphur existing as sulphate in the medium was 
precipitated by means of barium chloride, so that only the sulphur in 
organic composition remained, the same power was evinced. 
On raw eggs Proteus does not form H 2 S, though when the albumen 
is coagulated the production takes place as usual, whilst the albumen of 
bacteria cells coagulated during the process of sterilization is not 
decomposed with formation of H 2 S. 
The author also examined the formation of H 2 S by different bacteria 
from aqueous extract of asparagus which contains in organic and 
inorganic combination 0*00327 per cent, of sulphur. Results were 
similar to those obtained from animal media. 
Influence of Fatty Cultivation Media on Bacteria.* — According 
to Escherich the stools of healthy sucklings contain only a few and quite 
definite species of bacteria, which are decolorized with iodo-potassic 
iodide and anilin-xylol. It might have been expected that this behaviour 
would serve for recognizing bacteria present in the stools under patho- 
logical conditions, for the latter resist decoloration, appearing blue, 
while the normal faecal bacteria, when after-stained with aqueous solu- 
tion of fuchsin, are red. This supposition was, however, not confirmed 
in practice ; on the contrary, it was found that in those stools which 
might have been expected to have exhibited the most normal reactions, 
and in which even after most careful cultivation researches no species 
differing from B. coli commune could be found, the evacuations from 
healthy sucklings were almost exclusively blue, that is, no decolorizable 
rodlets were present, while in the diarrhoeic stools the red forms pre- 
dominated. 
At the suggestion of Emmerich, Herr A. Schmidt examined a large 
number of stools from healthy and sick suckling infants, and found that 
the blue greatly predominated in normal stools, whether the child was 
suckled by the mother or fed with cow’s milk. When the stools were 
clayey, the same reaction was observed, but when they were mucoid or 
watery, the red forms predominated. The bacteria from the small intes- 
tine were red, and those from the large were blue. But if some normal 
faeces were cultivated in bouillon, the blue were gradually replaced by 
red, slim organisms, and if plate cultivations were made from the bouillon 
at the time when blue forms predominated, colonies of B. coli commune , 
which are decolorized by Weigert’s method, were developed. 
* Wiener Klin. Wochenschr., 1892, No. 45. See Centralbl. f. Bakteriol. u. Parasi- 
tenk., xiii. (1893) pp. 761-2. 
