ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
471 
vaccinated against the most active virus are refractory to the less virulent 
microbes, but the converse does not hold good ; and those immunised 
against microbes of low virulence succumb to the injection of a microbe 
of greater virulence, though they exhibit a greater resistance than the 
control animals. 
Immunisation is also possible by means of the serum of vaccinated 
animals, but it is only transient ; yet there seems hope that an effective 
serum may eventually be obtained. 
Intestinal Vibrios and Cholera.* — Dr. J. Sanarelli considers that all 
vibrios are choleraic, and that water vibrios are neither the survivors 
of former epidemics nor common saprophytes, but are doubtless derived 
from the intestines of animals, and perhaps from man himself. Among 
the species of cholera vibrios are varieties furnishing toxic and vaccinating 
substances of different activities. And as regards the action of these 
vibrios on the organism, the author declares the peritonitis of guinea- 
pigs to bo devoid of specific characters, and would explain the morbid 
process occurring in the intestinal canal on the same lines. For here, 
too, the vibrios do not induce an infection nor a general intoxication ; 
they simply destroy the intestinal epithelium, thus converting an absorb- 
ing surface into a transudation one. Thus the poisoning of blood is not 
the cause of death in intestinal cholera ; the cholera toxins are not 
absorbed when the intestinal epithelium is intact, and there is no longer 
absorption when the epithelium is shed. 
Immunity to cholera cannot be conferred by attempting to impart 
preventive qualities to serum, nor by administering living vibrios 
by the stomach ; but a mild form of enteritis must be set up, which, 
if cured, may protect against a fatal enteritis, and this intestinal 
tolerance may be imparted by means of the vibrio toxins. Hence, as 
human cholera is but a toxic enteritis, there is a possibility of a pro- 
phylactic method, based on accustoming the intestine to the cholera 
poison, being realised. 
The author’s experiments, which are very numerous, are given with 
considerable amplitude of detail. 
Cholera Vibrio and Low Temperatures.! — The connection between 
cholera epidemics and water supply renders interesting the question 
whether the disease can be transferred by ice derived from contaminated 
streams. It has been stated several times that the cholera vibrio can 
bear cold for several days, and Dr. Weiss, on the strength of his experi- 
ments, is in a position to confirm the views of earlier observers in so far 
as they refer to water. Quite otherwise, however, are the vibrios affected 
by cold if they are present in a medium agreeable to them. In bouillon 
they live for 21 days, and in water containing much bouillon three days 
longer than in water to which only two drops of bouillon are added. In 
stools the cholera vibrios perish from cold more quickly than in water ; 
hence it would seem that when the vibrios and the stools reach running 
water the organisms die off in a few days. Consequently it is unlikely 
that the cholera vibrio can be transferred from ice, and this agrees 
with the fact that contagion from ice has not been observed. 
* Ann. Inst. Pasteur, ix. (1895) pp. 129-77 (2 pis.). 
t Zeitschr. f. Hygiene u. Infekt., xviii. (1894) pp. 492. See Centralbl. f. Bak- 
teriol. u. Parasitenk., l te Abt., xvii. (1895) p. 720. 
