BACTERIUM INFLUENZM 399 



It stains readily with all the ordinary aniline dyes. 



In tissues its presence is readily demonstrated by the 

 staining-method of Gram. 



The grouping into fours is particularly well seen in sec- 

 tions from the organs of animals dead of this form of septi- 

 cemia. In such sections the organisms will always be found 

 within the capillaries. 



Inoculation into Animals. — To the naked eye no altera- 

 tion can be seen in the organs of animals that have died as 

 a result of inoculation with sarcina tetragena; but micro- 

 scopic examination of cover-slip preparations from the blood 

 and viscera reveals the presence of the organisms throughout 

 the body — especially is this true of preparations from the 

 spleen. White mice and guinea-pigs are susceptible to the 

 disease. Gray mice, dogs, and rabbits are not susceptible 

 to this form of septicemia. Subsequent inoculation of 

 healthy animals with a drop of blood, a bit of tissue, or a 

 portion of a pure culture of this organism from the body of 

 an animal dead of this disease, results in a reproduction of 

 the conditions found in the dead animal from which the 

 tissues or cultures were obtained. 



It sometimes happens that in guinea-pigs which have 

 been inoculated with this organism local pus-formations 

 result, instead of a general septicemia. The organisms will 

 then be found in the pus-cavity. 



BACTERIUM INFLUENZ.a: (R. PFEIFFER), LEHMANN 

 AND NEUMANN, 1896. 



Stnonym: Influenza bacillus, R. Pfeiffer, 1892. 



An important historic epidemic disease, on the nature of 

 which much light has been shed through modern methods 



