_Vaccination prophylaxis_ against cholera has been less used than has been the case with plague or typhoid fever. The anti-cholera sera have no practical value prophylactically and the same statement applies to the use of such sera in treatment of cholera. Ferran, in 1885, was the first one to use cholera vaccines in prophylaxis. Haffkine, in 1893, adopted the use of a preliminary subcutaneous injection of an attenuated cholera organism to be succeeded later by one, the virulence of which had been exalted by passage through animals to a fixed virulence. (Pasteur’s anthrax method.) He now only uses the fixed virulence vaccine. This vaccine is not killed by heat. The statistics indicate quite a reduction in susceptibility on the part of vaccinated persons (probably 8 to 1) but only slight lessening of mortality rate. Of 5549 nonvaccinated 198 contracted cholera and 124 died. Of 5778 vaccinated 27 contracted cholera and 14 died. In the recent Balkan war (1913) Kolle’s vaccine was employed with considerable success. This vaccine is killed by exposure to 58°C. for one hour. It was found that this vaccine was not only of value prophylactically but diminished case mortality as well. With 91,224 persons vaccinated and 8,968 not vaccinated, the case rate among the inoculated was 0.7% and the death rate 10.2%, while among the noninoculated the case rate was 9.3% and the death rate 27.5%. Ottolenghi prefers to sterilize with a temperature of 53°C. He gives 500 million at the first injection and 2 billion at the second. Among 72,653 soldiers, having 2 inoculations of this vaccine, the incidence of cholera was about 13 times less than among 14,332 who were not vaccinated. Of 2897 Greek sanitary corps men inoculated 0.45% were attacked while of 114,805 combatants, not inoculated, about 2% were attacked by cholera. One would naturally consider the greater exposure of the sanitary forces. Cholera vaccines made from killed cultures are the ones now generally used. During the World War a Roumanian regiment numbering 4,500 soldiers, had 386 cases of cholera develop in the course of six days, with 166 deaths. Vaccination was commenced and during the interval between the first and second injections, new cases continued to appear. Two days after the second injection the epidemic ceased. In another regiment the commandant refused to have his men vaccinated. A group of Jewish soldiers, 200 in number, insisted on being vaccinated, which was done. Later the regiment was stricken by cholera and 450 cases developed. None of the vaccinated Jewish soldiers contracted the disease. Some prefer sensitized living cultures for prophylaxis but such vaccines are less practical.