562 APPLICATION OF METHODS OF BACTERIOLOGY 



ture methods the organisms are found present in the small 

 intestine in practically pure culture. 



Later Pfeiffer 1 determined that essentially similar con- 

 stitutional effects may be produced in guinea-pigs by the 

 intraperitoneal injection of relatively 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 virulent 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 

 usually occurs in from eighteen to twenty-four hours after 

 the operation, though exceptionally the animal recovers, 

 even after having exhibited marked symptoms of profound 

 toxemia. 



Continuing his studies upon this disease, Pfeiffer 2 demon- 

 strated that it is possible to render an animal 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 demonstrated 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 relatively 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 protected, and imme- 



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. 



