CHAPTER XI. 



BACILLUS TYPHOSUS. 



(Bacillus Typhi Abdominalis ; Bacillus of Eberth; Eberth- 

 Gaffky Bacillus.) 



THE bacillus of typhoid fever was discovered by both Eberth 

 and Koch, in 1880, in the spleen and mesenteric lymph- 

 glands of typhoid cadavers, and was first isolated and studied 

 in pure cultures by Gaffky four years later. 



Biology and morphology : Bacillus typhosus is a small thick 

 rod, with pointed ends and from ten to eighteen terminal and 

 lateral flagella. It is exceedingly motile. It measures from 



FIG. 122. 



FIG. 123. 



Typhoid bacilli from nutrient agar. 

 X 1100. (Park.) 



Typhoid bacilli from nutrient gelatin. 

 X 1100. (Park.) 



1 n to 3 [i. in length, and from 0.5 // to 0.8 // in width. There 

 is no evidence of sporulation. The organism is extremely 

 variable in cultures. In specimens made directly from the 

 tissues or typhoid excreta the germ usually occurs singly ; 

 but in culture specimens it is frequently seen to form chains, 

 both long and short (Figs. 122, 123). 



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