SPIRILLUM CHOLERA ASIATICS. 459 



More recently Pfeift'er ' has determined that essen- 

 tially similar constitutional effects may be produced in 

 guinea-pigs by the intraperitoneal injection of rela- 

 tively large numbers of this organism. His plan is to 

 scrape from the surface of a fresh culture on agar-agar 

 as much of the growth as can be held upon a medium 

 size wire loop. This is then finely divided in 1 c.c. 

 of bouillon, and by means of a hypodermic syringe is 

 injected directly into the peritoneal cavity. When vir- 

 ulent cultures have been used this operation is quickly 

 followed by a fall in the temperature of the animal that 

 is gradual and continuous until death ensues, which usu- 

 ally occurs in from eighteen to twenty-four hours after 

 the operation, though exceptionally the animal recovers, 

 even after having exhibited marked symptoms of pro- 

 found toxaemia. 



Continuing his studies upon this disease, Pfeiffer ^ has 

 demonstrated that it is possible to render an animal tol- 

 erant to or immune from the poisonous properties of this 

 organism by repeated injections of non-fatal doses of 

 dead cultures (cultures that have been killed by the 

 vapor of chloroform or by heat). He also demon- 

 strated that animals so immunized possess a specific 

 germicidal action toward the cholera spirillum — i. e., if 

 into the peritoneal cavity of an animal immunized from 

 Asiatic cholera living cholera spirilla be introduced, 

 they will all be destroyed (disintegrated) within a rela- 

 tively short time. Furthermore, if the serum of an animal 

 immunized from cholera be injected into the peritoneal 

 cavity of another animal of the same species, but not so 



1 Zeitschrift fur Hygiene und Infektionskraukheiten, Bd. xi. and xiv. 



2 Ibid., 1894, Bd. xvii. S. 355; 1894, Bd. xvili. S. 1; 1895, Bd. xx. 

 S. 197. 



