SPIRILLUM CHOLERA ASIATICS. 579 



weakened by the fact that experiments made with 

 some other bacteria viz., those isolated by Finkler and 

 Prior, Deneke, and Miller, and morphologically similar 

 to the comma bacillus of Koch occasionally pro- 

 duced death when introduced in the same way into 

 the small intestines of guinea-pigs; but while only 

 twelve out of fifty-one animals died when injected 

 with cultures of these last-mentioned bacteria, in the 

 cholera experiments there was 90 per cent, of deaths, 

 and when larger doses were administered all of the 

 animals died. Control experiments made with many 

 other bacteria gave negative results. Intraperitoneal 

 injections of larger quantities of pure cholera cultures 

 also often produce death in rabbits and mice. 



There are several cases on record which furnish the 

 most satisfactory evidence that the cholera bacillus is 

 able to produce the disease in man. In 1884, a student 

 in Koch's laboratory in Berlin, who was taking a course 

 on cholera, became ill with a severe attack of cholera. 

 At that time there was no cholera in Germany, and the 

 infection could not have been produced in any other 

 way than through the cholera cultures which were being 

 used for the instruction of students. In 1892, Petten- 

 kofer and Emmerich experimented on themselves by 

 swallowing small quantities of fresh cholera cultures 

 obtained from Hamburg. Pettenkofer was affected 

 with a mild attack of cholerine or severe diarrhoea, from 

 which he recovered in a few days without any serious 

 effects; but Emmerich became very ill. On the night 

 following the infection he was attacked by frequent evac- 

 uations of the characteristic rice-water type, cramps, 

 tympanitis, and great prostration. His voice became 

 hoarse, and the secretion of urine was somewhat dimiu- 



