SPIRILLUM OF ASIATIC CHOLERA. 379 



stomach and intestines do not contain solid masses, but 

 fluid; when diarrhoea does not occur, firm scybala may 

 be expected in the rectum. Both by microscopic exam- 

 ination and by culture methods comma bacilli are found 

 to be present in the small intestine in practically pure 

 culture. 



More recently Pfeiffer^ 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 moderate- 

 sized 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 is quickly followed 

 by a fall in the temperature of the animal; this is grad- 

 ual and continuous until death ensues, which is usually 

 in from eighteen to twenty-four hours after the opera- 

 tion, though exceptionally cases do occur in which the 

 animal recovers, even after hanng exhibited marked 

 symptoms of most profound toxaemia. 



In pursuance of his studies upon this disease Pfeiffer^ 

 has demonstrated that it is possible to render an animal 

 tolerant or immune to 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 immuned possess a specific 

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

 into the peritoneal cavity of an animal immunized from 



1 Zeitschrift fUr Hygiene, Bd. xl. and xiv. 



* Zeit. fur Hyg. u. Infectionskrankheiten, Bd. ix. Heft. i. 



