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SUMMARY OF CURRENT RESEARCHES RELATING TO 
Asiatic Cholera in Guinea-pig 1 .* — M. Haffkine has increased and 
diminished the virulence of the cholera vibrio in the same way as has 
been done for the bacilli of fowl-cholera, anthrax, &c. 
In order to increase the virulence he took from an agar surface a more 
than fatal quantity of pure cultivation and injected it into the abdominal 
cavity: of an animal, and then, having exposed this overflow fluid for 
several hours at the ordinary temperature of the air, inoculated other 
animals therewith. When the poison has in this way passed through 
several animals it becomes constant, that is, a definite quantity kills the 
animals in the same time. Animals injected deep in the muscles 
succumb ; after inoculation in the subcutaneous cellular tissue an exten- 
sive oedema arises, leading to necrosis of the tissue, though the animal 
survives. 
In order to weaken the poison, the author cultivated the cholera 
vibrio at 39°, under continual exposure to the air. As subjects soon die 
under this treatment they must be transferred every 2-3 days to fresh 
media, and in this way Haffkine succeeded in obtaining cultivations, the 
subcutaneous inoculation of which was without deleterious consequence. 
This was the virus employed as protective against Asiatic cholera. 
After preliminary inoculation therewith in the subcutaneous cellular 
tissue, the guinea-pigs bore a similar inoculation with the strong virus 
without detriment, and an animal doubly inoculated in this way is proof 
against any inoculation with the cholera virus, and also proof against 
inoculation through the stomach, when the physiological action of the 
gastro-intestinal tract has been previously inhibited by opium. 
Lasting Abolition of the Chromogenic Function of Bacillus pyo- 
cyaneus-t — MM. Charrin and Phisalix have succeeded in depriving 
B. pyocyaneus of its chromogenic function by growing it for several 
successive generations at 42° *5. The modification thus acquired was 
transmitted hereditarily, and was retained by descendent cultivations 
though placed in the most favourable conditions as to temperature and 
medium. 
The cultivations were carried to the sixth generation, and that the 
colonies were those of decolorized B. pyocyaneus was verified by 
experiments on animals ; these suffered from the symptoms produced by 
B. pyocyaneus poisoning, and showed all the lesions found in this 
disease. 
Behaviour of Typhoid Bacilli in the Soil.f — From experiments 
Dr. J. Karlinski finds that the typhoid bacillus behaves as follows in 
the soil: — (1) It may remain alive for more than three months. (2) 
The duration of life of the bacillus when buried in the soil along with 
the dejections and left there under ordinary conditions is considerably 
less than that of bacilli obtained from the blood and buried in the soil 
in the condition of a pure cultivation ; this is probably due to the active 
competition of other bacteria in the faeces. (3) In the deep layers of 
the soil, the typhoid bacilli are able to resist changes of temperature 
* La Semaine Med., 1892, No. 36. See Centralbl. f. Bakteriol. u. Parasitenk., 
xii. (1892) pp. 258-9. t Comptes Rendus, cxiv. (1892) pp. 1565-8. 
X Archiv f. Hvgiene, xiii. p. 302. See Annales de Micrograpkie, iv. (1892) 
pp. 353-4. 
