CHOLERA TOXINS 537 



alkali-albumin, egg, and Uschinsky medium, cultures. 

 This observer also found aerobic cultures of the cholera 

 vibrio to be much more toxic than anaerobic ones. 



Pfeiffer found that cholera cultures killed with chloro- 

 form vapour contained a toxic substance fatal to guinea- 

 pigs in small doses, with extreme collapse. He believed 

 the substance to be an integral part of the bacterial cells. 



Metchnikoff, 1 Roux and Salimbeni demonstrated the 

 existence of a soluble cholera-poison in an ingenious 

 manner. Collodion sacs of 2 c.c. to 3 c.c. capacity were 

 sterilised, filled with peptone solution, inoculated with 

 the cholera spirillum, and closed. The closed sac was 

 then introduced into the peritoneal cavity of a guinea-pig, 

 which died in three or four days from the effects of the 

 soluble toxins dialysing through the walls of the sac (see 

 also below). 



Brau and Dernier 2 obtained a toxic filtrate by culti- 

 vating the cholera vibrio in a medium consisting of horse 

 serum with an addition of 10 per cent, of defibrinated 

 horse blood. 



Macfadyen obtained a highly toxic endotoxin by 

 triturating cholera cultures with liquid air. 3 



Emmerich 4 advanced the view that the cholera intoxi- 

 cation is not a toxin intoxication, but is due to nitrite 

 poisoning, the nitrites being produced by the reducing 

 action of the vibrios on nitrates present. 



Anti-serum. By growing the cholera vibrio in a shallow 

 layer with free access of oxygen in a peptone-gelatin-salt 

 medium, Metchnikof? and his co-workers obtained a toxic 

 fluid after three or four days' growth. After filtration, 

 0-25 c.c. killed a 300-grm. guinea-pig in eighteen hours. 



1 Ann. de VInst. Pasteur, x, 1896, p. 257. 



2 Ibid., xx, 1906. 



3 Lancet, 1906, vol. ii, p. 494. 



4 Munch, med. Wochenschr., 1911, No. 18, p. 942. 



