538 A MANUAL OF BACTERIOLOGY 



Goats, inoculated with increasing doses of this toxin, 

 commencing with 10 c.c. and reaching 200 c.c. in six 

 months, become immunised and yield an antitoxic serum, 

 1 c.c. of which will neutralise four times the lethal dose of 

 toxin. Metchnikoff had previously found that young 

 suckling rabbits suffer from an intestinal cholera when fed 

 with cultures, so that the effect of the cholera antitoxin 

 in preventing intestinal cholera could be tested on these 

 animals. Experiment showed that of the treated rabbits, 

 51 per cent, survived, of the untreated only 19 per cent. 

 Salimbeni employed a serum prepared in this manner in the 

 treatment of cases of cholera in the Russian epidemic, 1910. 



Animals inoculated first with dead, and subsequently 

 with living, cultures yield an immune serum which is 

 actively agglutinating and experimentally is protective 

 against, and curative for, infection with the living vibrio, 

 but is useless for the treatment of the disease. Macfadyen 

 immunised a goat with cholera-cell juice, and obtained a 

 serum of which ^J^ c.c. protected a guinea-pig against 

 three lethal doses of cholera culture. 



The writer prepared an anti-endotoxic serum in this 

 manner, with which a few cases of cholera were treated 

 in Russia. 1 



Vaccine. Ferran in 1885 was the first to prepare and 

 use a vaccine for immunisation against cholera. His 

 vaccine consisted of a broth culture made from cholera 

 stools and was a mixed culture. A commission which 

 investigated the results obtained reported unfavourably 

 upon the method. 



Haffkine subsequently prepared a vaccine against 

 cholera which has been extensively used. In the Haffkine 

 method two vaccines are made use of. The first or 

 weak vaccine is prepared from cultures of the cholera 

 vibrio attenuated by growing on the surface of agar, 



1 Lancet, 1910, vol. ii, October 22. 



