612 
SUMMARY OP CURRENT RESEARCHES RELATING TO 
typhosus. lie finds that Bad. coli presents two appearances on gelatin, 
viz. a membraniform film and points. Gelatin is not liquefied ; milk is 
coagulated ; and on saccliarated media gas is developed. Spore-formation 
was not observed. This microbe is easily stained with anilin pigments, 
but not by Gram’s method. In size and shape the organisms obtained 
from different sources were much alike, though those from man exhibited 
very lively movements, while those from the rabbit were very sluggish. 
Potato cultivations exhibited well-marked colour differences, the Bad. 
coli being mostly of an orange hue. Bac. typhosus was scarcely visible. 
The author finds that there are distinct differences between the two 
kinds of bacteria. B. typhosus is more mobile, and possesses several 
flagella which are easily stained. Bad. coli has usually only one 
flagellum which is difficult to stain. Bad. coli gives the indol reaction 
(1 ccm. of 0 02 per cent, nitrite of potash and some diluted sulphuric 
acid are added to a pepton cultivation). Bac. typhosus does not. The 
latter has a great tendency to form filaments from the connection of 
several individuals. Bad. coli is a rodlet 1-3 mm. long and about 
0*8 mm. broad, usually single, though occasionally in pairs. Bad. coli 
grows faster on agar and gelatin than Bac. typhosus. 
Dr. Inghilleri * points out that since Rodet and Roux published their 
researches on the identity of these bacteria, their observations have been 
frequently supported and controverted. The balance of opinion seems 
to incline to the view that, while there are actual differences between the 
two organisms, they have probably originated from the same stock. 
According to the author these microbes behave differently in media con- 
taining amygdalin, for while the reaction of bouillon cultures of B. coli 
is acid and the odour of bitter almonds can be perceived in about thirty- 
six hours, the reaction of a culture of typhus is alkaline. This difference 
is supposed to be due to the fact that B. coli acts like emulsin in splitting 
up the complex molecule of the glucoside into the simpler one of grape 
sugar, prussic acid, and benzaldehyd. The acid reaction depends on the 
fact that B. coli acts successively on glucose, and decomposes its molecule 
into carbonic acid and lactic acid. The author made use of the Gruber- 
Bercholtz reaction to demonstrate glucose. The prussic acid was first 
eliminated by the aid of caustic potash and then demonstrated by means 
of the Berlin blue reaction. In the typhus cultures nothing of the sort 
takes place. 
The author is of opinion that this property of B. coli is associated 
with the life of the bacillus, since a sterilized culture has no such action. 
Cholera Vibrio and Diagnosis of Cholera.f — Prof. M. Gruber, while 
agreeing with Koch’s views in the main, rejects most of the tests sup- 
posed to be diagnostic of the V. choleras asiaticae. The only one which 
the author finds to be of any value is the microscopical appearance of 
quite young colonies in 10 per cent, gelatin. The observations, how- 
ever, must be made under certain definite conditions to be reliable, and 
the colonies inspected under magnifications of 80 to 120. The gelatin 
must be always of the same composition, prepared according to the method 
of Petri and Maassen, and rendered sufficiently alkaline to give the 
reaction with rosalic acid. 
* Centralbl. f. Bakteriol. u. Parasitenk., xv. (1894) p. 821. 
f Lancet, July 7 and 14, 1894 
