100 ESSENTIALS OF BACTERIOLOGY 



growth, cultures, and properties are the same as the pneumo- 

 bacillus of Friedlander. 



Bacillus of Influenza (Pfeiffer, 1892). Origin. One of 

 the smallest of the known bacilli, 1.5 // by 0.3 /j, about one- 

 half the size of the bacillus of mouse septicemia, and ar- 

 ranged in chain form. It develops upon blood-serum agar. 

 It is aerobic, without movement (Fig. 74). 



Stain. It is best stained with diluted carbol-fuchsin, the 



. ,r \ . - 



?* 



.. 

 ' 



;.""w*. 



Fig. 74. Bacillus influenzae, from a gelatin culture (Xiooo) (Itzerott 

 and Niemann). 



contrast-stain being Loffler's methylene-blue; does not take 

 the Gram stain. 



Growth. Upon blood-agar or glycerin-agar, over which a 

 drop of blood has been spread, in an incubator at 37 C. at 

 the end of twenty-four hours a very delicate growth occurs 

 which resembles condensed moisture. Very small colonies, 

 never larger than a pinhead, feebly resistant. Subcultures 

 must be made every few days. 



Pathogenesis. It is found in the sputum and in the bron- 

 chial and nasal secretions and blood of influenza patients. It 



