496 



Relapsing Fever 



of the same thing caused by the same parasite, or whether they 

 are different diseases caused by slightly different parasites. 



If Nuttall be correct, there are no adequate grounds upon which 

 to conclude that the spirochetes are really different species. On 

 this account, and as the differences between the organisms are 

 minute, it scarcely seems well to devote space to the consideration 

 of each, but better to select the oldest and the best known — Spiro- 

 chasta obermeieri — as the type, describe it, and then point out such 

 variations as are shown by its close relations. 



Morphology. — The Spirochseta obermeieri is e^ctremely slender, 

 flexible, spirally coiled, like a corkscrew, and pointed at the ends. 



Fig. igp. — Spirochseta obermeieri (Novy). Rat blood No. 321a. X 1500. 



It measures approximately i m in breadth and 10, 20, or even 40 n 

 in length. The number of spiral coils varies from 6 to 20; the di- 

 ameter of the coils varies so greatly that scarcely any two are uni- 

 form. Wladimiroff * doubts the existence of a flagellum,but flagella- 

 like appendages are usually to be seen at one or both ends of the 

 organisms. An undulating membrane attached nearly the entire 

 length of the organism, very narrow, and inconspicuous, forms the 

 chief means of locomotion. The organism is actively motUe, 

 and darts about in fresh blood with a double movement, consisting 

 of rotation about the long axis and serpentine flexions. No structure 

 can be made out by our present m.ethods of staining and examining 

 the spirochaeta. No spores are found. Multiplication is thought 

 to take place by longitudinal division, though some believe the di- 

 vision to be transverse. 



*"KoIle and Wassermann's Handbuch der pathogene Mikrobrganismen," 

 1903, III, p. 82. 



