400 APPLICATION -OF METHODS OF BACTERIOLOGY 



of investigation, is influenza. Quoting Hirsch: — the first 

 trustworthy literary records that we have of this disease 

 date from the parly part of the twelfth century. 



Between 1173 and 1874 it made its epidemic or pandemic 

 appearance on eighty-six different occasions. Its first 

 appearance in this country was in Massachusetts in 1672; 

 since that time there have been twenty-two visitations of 

 influenza in the United States. The pandemic 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 com- 

 munity is always remarkable for its astonishing rate of 

 transmission from person to person and its dissemination 

 over wide areas. 



During the recent pandemic investigations having for 

 their object the discovery of its cause were instituted, 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. 



By appropriate methods of staining it is also frequently 

 possible to demonstrate the presence of this organism in 

 the secretions of the nose, mouth, and throat of apparently 

 healthy persons, as well as in those from persons suffering 

 from such diseases as diphtheria, scarlet fever, measles, etc. 



This organism, bacterium influenzae, as it is called, was 

 discovered, isolated, cultivated, and described by R. Pfeiffer. 



It is a very small, slender, non-spore-forming, non-motile, 

 aerobic bacillus, occurring singly and in pairs, joined end 

 to end. It stains with watery solutions of the ordinary 

 basic aniline dyes; somewhat better with alkaline methylene- 

 blue, but best when treated for five minutes with a dilution 

 of Ziehl's carbol-fuchsin in water (the color of the solution 



