CHAPTEE VIII. 

 INFLUENZA. 



The specific organism was discovered in 1892 — Method of staining — 

 Growth on media — Epidemics of note — The disease has produced 

 different clinical effects in different years — An attack is not protective 

 — Prophylaxis. 



The organism causing this disease was first described by 

 Pfeiffer in the year 1892. It is found in the sputum and 

 blood of influenza patients during the febrile period ; it is a 

 very small rod with rounded ends, and is generally found 

 in pairs, but on cultivation grows out into strings in a 

 similar way to anthrax. 



Metliod of Staining. — The bacillus stains with some 

 difiiculty ; it is best stained with warm carbo-fuchsine, or 

 Loffler's methylene blue. It is not stained by Gram's 

 method. 



Growth on Media. — The influenza bacillus grows in stab 

 culture in grape-sugar agar at 37° C, in a thin whitish 

 streak, exhibiting no distinctive characters. On the surface 

 of glycerine agar on which a few drops of blood have been 

 smeared it forms small transparent colonies which are per- 

 ceptible with difficulty. It grows in broth containing 

 grape-sugar and glycerine, and in the case of all media it 

 must be subcultured every eight days at least, or its 

 vitality will be lost. 



