Cultivation 497 



The Spirochaeta duttoni is said by Koch,* in his interesting 

 studies of " African Relapsing Fever," to resemble the Spirochaeta 

 obermeieri in all particulars. 



The Spirochaeta novyi with which Novy and Knappf experi- 

 mented, and which they believed to be identical with Spirochaeta 

 obermeieri, measured 0.25 to 0.3 JJL in breadth by 7 to 19 n, in length. 

 The number of coils varies from three to six. The shorter forms are 

 pointed, with a long flagellum at one end and a short one at the 

 other. 



Staining. The Spirochaeta can be stained with ordinary anilin 

 dye solutions, by the Romanowsky and Giemsa methods, and by 

 the silver methods (see Treponema pallidum). It does not stain 

 by Gram's method. 



Fig. 200. Spirochaeta duttoni (Novy). Tick fever, No. 520. Rat blood. 



X 1500. 



Cultivation. -Following the suggestion of Levaditi, Novy and 

 Knappt cultivated Spirochaeta obermeieri in collodion sacs in the 

 abdominal cavity of rats, and succeeded in maintaining it alive in 

 this way through twenty consecutive passages during sixty-eight 

 days. They were able to do this in rat serum from which all cor- 

 puscles had been removed by % centrif ugation, and so proved that 

 no intercellular developmental stage of the organism takes place. 

 Organisms thus cultivated attenuate in virulence. 



Norris, Pappenheimer, and Flournoy believe that they succeeded 

 in securing multiplication of the Spirochaeta by placing several drops 



"Berliner klin. Wochenschrift," Feb. 12, 1906, xxxrv, No. 7, p. 185. 

 ' "Jour. Infectious Diseases," 1906, in, p. 291. 

 j "Jour. Amer. Med. Assoc.," Dec. 29, 1906, XLVII, p. 2152. 

 "Journal of Infectious Diseases," 1906, HI, 266. 

 32 



