ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
499 
Berlin. From the cholera vibrio it is chiefly distinguished by its growth 
on gelatin and agar plates. In the first case, instead of the granulation 
occurring in about thirty-six hours, there is obvious mycele formation, 
while in the second the colonies have a whitish centre clearly visible 
with a hand-lens, the cholera colonies being quite transparent. A 
further criterion is to be found in the size of the new vibrio and its 
tendency to form spirilla. Products of 24-hour old agar cultivations 
killed guinea-pigs in 10-12 hours with symptoms like those of cholera 
intoxication. Pigeons, rats, and mice were refractory, but rabbits 
succumbed to a large dose. 
Cholera Bacillus and Tobacco.* — Dr. Wernicke states that the 
cholera bacillus speedily perishes on tobacco-leaves, even when moist, 
and that therefore any danger of the spread of cholera from tobacco or 
cigars is but slight. 
Artificial Variation of the Cholera Vibrio, j — Prof. E. Metchnikoff 
is of opinion that there are two types of vibrios which retain their 
peculiarities, both under natural and artificial conditions. The types, 
distinct enough in appearance, are short, curved vibrios (the comma 
bacillus type, in fact), and long, thin filaments, sometimes almost 
straight, sometimes twisted into spirals with several turns. The short 
and long vibrios are not two constant types, but simply form two 
races which may be transformed the one into the other, according to 
external circumstances. To turn the elongated vibrio into the squat 
shape, all that is necessary is to inoculate it on a guinea-pig and then 
make cultivations from the peritoneal exudation on agar, while in old 
cultivations the short vibrio will become a thin elongated organism. 
As a rule, however, these transformations have little stability and, to 
effect a durable change, the vibrios must be exposed for a long time 
to influences acting slowly. Like the shape, the virulence of the vibrio 
is liable to considerable variations, though the two are not necessarily 
connected ; thus while a particular variety will retain its shape for a 
considerable period, its virulence is liable to undergo very notable 
variations. From a review of all the facts, it would seem impossible to 
deny that this case of the cholera vibrio might be cited as a striking 
example of pleomorphism, and hence its bacteriological diagnosis may 
present insuperable difficulties. 
Coli Group of Bacteria.^ — Dr. H. de Stoecklin contributes an inter- 
esting memoir on the Coli group of organisms, and his conclusions are that 
(1) the term Bad. coli commune includes a group of intestinal bacteria, 
the predominating character of which is that they do not liquefy gelatin, 
and are not stainable by Gram’s method ; (2) the group includes both 
mobile and immobile species, about 2/5 of the whole being mobile; 
(3) when the species is mobile, the mobility is extreme, and never 
sluggish ; (4) by means of Loeffler’s method of staining cilia the Coli 
group is easily distinguishable from the bacillus of enteric fever. 
* Centralbl. f. Bakteriol. u. Parasitenk, xv. (1894) p. 898. 
f Ann. Inst. Pasteur, viii. (1894) pp. 257-74. 
X Ann. Suisses des Sciences Medicates, 1. No. G. See Ann. de Micrographie, vi. 
(1814) pp. 238-9. 
