MICROSPIRA METCHNIKOVI 579 



pectoral muscle atrophies, the pigeon loses in weight and 

 finally dies after one or two weeks. In these cases the 

 organisms are usually absent from the blood and internal 

 organs, and may even be absent from the site of inoculation, 

 or, if present, in only very small number. 



Guinea-pigs usually die in from twenty to twenty-four 

 hours after subcutaneous inoculation. At autopsy an 

 extensive edema of the subcutaneous tissues about the seat 

 of inoculation is seen, and there is usually a necrotic condi- 

 tion of the tissues in the vicinity of the point of puncture. 

 As the blood and internal organs of both pigeons and guinea- 

 pigs contain the vibrios in large numbers, the infection in 

 these animals takes, therefore, the form of acute, general 

 septicemia. 



The blood-serum of both pigeons and guinea-pigs that 

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

 have acquired immunity from it is bactericidal in vitro 

 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 become 

 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 mat- 

 ters 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. (Gamalei'a.) 



