470 BACTERIOLOGY. 



mal usually dies after remaining in this condition for a 

 few hours. 



At autopsy the small intestine is found deeply in- 

 jected and filled with flocculent, colorless fluid. The 

 stomach and intestines do not contain solid masses, but 

 fluid ; when diarrhoaa does not occur, firm scybala may 

 be detected in the rectum. Both by microscopic exam- 

 ination and by culture methods the organisms are 

 found present in the small intestine in practically pure 

 culture. 



More recently Pfeiffer 1 has determined that essen- 

 tially similar constitutional eiFects 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, Pfeiifer 2 has 

 demonstrated that it is possible to render an animal 

 immune from the poisonous properties of this organism 



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



2 Ibid., 1894, Bd. xvii. S. 855; 1894, Bd. xviii. S. 1; 1895, Bd. xx. 

 S. 197. 



