490 BACTERIOLOGY. 



large numbers, the infection in these animals takes, 

 therefore, the form of acute, general septicsemia. 



The blood-serum of both pigeons and guinea-pigs 

 that have survived inoculation with this organism — i. e., 

 that have acquired immunity from it — are bactericidal 

 in vitrio for this organism. It also possesses a certain 

 degree of immunity-conferring property, as may be 

 demonstrated by injecting it into normal pigeons and 

 guinea-pigs that are subsequently to be inoculated with 

 virulent cultures. 



Very old cultures of this organism in bouillon be- 

 come distinctly alkaline in reaction. At this stage they 

 contain a toxin that is markedly active for susceptible 

 animals. This toxin is not dissolved in the fluid to any 

 extent, but is apparently in intimate association with the 

 proteid matters composing the bacteria. 



Gastro-enteritis may be produced in both chickens 

 and guinea-pigs by feeding them with food with which 

 cultures of this organism have been mixed. (Gamaleia.) 



In the autumn of 1896 the author isolated from the 

 water of the Schuylkill River at Philadelphia a spirillum 

 that is pathogenic for pigeons and guinea-pigs, and 

 that possesses so many of the other characteristics 

 common to the group of spirilla of which the chol- 

 era spirillum is the most important member, as to justify 

 the opinion that they are of the same family. That it 

 is not identical with the cholera spirillum is evident, 

 for the reason that the latter produces cholera, while 

 the vibrio Sehuylkilliensis manifestly does not.' 



1 For the detailed description of tliis organism, see Journal of Ex- 

 perimental Medicine, vol. i. p. 419 ; also Transactions of the Association 

 of American Physicians, 1896, vol. xi. p. 394. 



