BACTERIUM INFLUENZA. 341 



domic appearance on eighty-six different occasions. Its 

 first appearance in this country was in Massachusetts in 

 1627 ; since that time there have been twenty-two vis- 

 itations of influenza to the United States. The pan- 

 demic of 1889-'90, the most severe for a long time, 

 appears to have originated in Central Asia and to have 

 spread pretty much over the entire civilized world. The 

 advent of influenza in a community is always remark- 

 able for its astonishing rate of transmission from per- 

 son to person and its dissemination over wide areas. 



During the recent pandemic investigations having 

 for their object the discovery of its cause were insti- 

 tuted, with the result of demonstrating in the catarrhal 

 secretions from the air-passages a micro-organism that 

 is claimed to stand in causal relation to influenza. 



Auerbach l examined over 700 cultures prepared from 

 cases of diphtheria and scarlet fever for the presence 

 of the influenza bacillus, and had 38 positive results, of 

 which 12 were from cases of diphtheria, 3 from scarlet 

 fever, 6 from diphtheria and scarlet fever, 7 from diph- 

 theria and measles, and 10 from suspicious diphtheria 

 angina. He employed the culture, and also the staining, 

 methods on pigeon-blood agar, the latter consisting in 

 the staining of the preparations with the Gram-Weigert 

 stain, followed with a diluted carbol-glycerine-fuchsin 

 stain. By this staining method it was not at all difficult 

 to detect the presence of bacterium influenzas. It ap- 

 peared as thin reddish-violet rods in contrast to the dark 

 blue diphtheria organisms and streptococci and pneu- 

 mococci. 



By appropriate methods of staining it is also fre- 

 quently possible to demonstrate the presence of this 

 1 Auerbach : Zeitschr. f. Hygiene, Bd. 47, 1904, p. 259. 



