Morphology 621 



Spirochaete obermeieri as the type, and point out such 

 variations as are shown by its close relations. 



General Characteristics. An elongate, flexible, flagellated, non- 

 sporogenous, actively motile spiral organism, pathogenic for man and 

 monkeys, not susceptible of cultivation in artificial media, stained by 

 ordinary methods, but not by Gram's method. 



Morphology. The Spirochaete obermeieri are extremely 

 slender, spirally coiled, like a corkscrew, pointed at the 

 ends. They measure approximately i //. in breadth and 

 10, 20, or even 40 p- in length. The number of spiral coils 



Fig. 184. Spirochaete duttoni (Novy). Tick fever No. 520. Rat 

 blood. X 1500. 



varies from 6 to 20 ; the diameter of the coils varies so greatly 

 that scarcely any two are uniform. Wladimiroff * doubts the 

 existence of a flagellum, but flagella-like appendages are 

 usually to be seen at one or both ends of the organisms. 

 The organism is actively motile, 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 methods of staining and exam- 

 ining the spirochaetes. No spores are found. Multiplication 

 is by transverse division only. 



* "Kolle and Wassermann's Handbuch der pathogenic Mikroorgan- 

 ismen," 1903, HI, p. 82. 



