MICROSPIRA COMMA. 487 



More recently Pfeiffer 1 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 

 si/e 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 kmemia. 



Continuing his studies upon this disease, Pfeiffer 2 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 microspira comma i. e., if 

 into the peritoneal cavity of an animal immunized 

 from Asiatic cholera living organisms 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 Infektionskrankheiten, Bd. xi. and xiv. 



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

 S. 197. 



