CHAPTER XXII 



(1) HEMOGLOBINOPHILIC GROUP. (2) HEMORRHAGIC 

 SEPTICEMIA GROUP 



(1) B. INFLUENZA. B. OF KOCH-WEEKS. B. PERTUSSIS. 

 B. OF SOFT CHANCRE 



B. Influenzas. Influenza was described as early as the fifteenth 

 century although in all probability it was known even earlier. 

 It has appeared in all parts of the world sporadically in epidemics 

 or in great pandemics. In 1889-1890 so widespread was the disease 

 and so high the mortality that it was considered the most serious 

 pandemic of modern times. During the two years following 

 many attempts were made to discover the specific cause, and in 

 January, 1892, Pfeiffer, Kitasato, and Canon simultaneously pub- 

 lished a description of the organism now known as B. influenzas. 

 Pfeiffer's work was the most complete and to it is due most of 

 the knowledge we possess of the organism. B. influenzas has 

 been definitely shown to be pathogenic and is generally accepted 

 as the cause of the disease although the fact has not been abso- 

 lutely proved. 



Morphology and Staining. The organism is one of the smallest 

 pathogenic bacteria known. As seen in film preparations from 

 sputum it averages from 0.5 to 1.5 p in length and 0.2 to 0.3 /*> 

 in width. The ends of the rod are rounded and no capsule is 

 formed. The organism is Gram negative and is colored rather 

 faintly with the ordinary anilin dyes. Staining is best effected 

 with a 1 in 10 solution of carbol fuchsin for five to ten minutes. 

 It is non-motile and does not form spores. 



Cultivation. Pfeiffer succeeded in growing the organism in 

 symbiosis with others on agar smeared with sputum, but all at- 



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