xiu.] SPIROBACTERIUM. 135 



relapsing fever. Tlie spirilla disappear from the blood during 

 the non-febrile stages, gradually decreasing in numbers. They 

 are motile ; they come out well in specimens of blood made 

 after the Weigert-Koch method of drying the blood in a very 

 thin layer, and then staining with methyl- violet or Bismarck- 

 brown. 1 H. V. Carter 2 succeeded in producing relapsing 

 fever in monkeys by inoculation with human blood containing 

 the spirillum Obermeyeri. The blood in the monkey contained 

 the same spirilla in great numbers. Koch has cultivated arti- 

 ficially the spirilla Obermeyeri, and saw them growing into 

 long spiral threads. 3 



1 Weigert. Deutsche med. Woch. 1876 ; Heydenreich, Berlin, 1877. 



2 Lancet, 1879, vol. i. p. 84 ; and 1880, vol. i. p 662. 



3 Deutsche med. Woch. 19, 1879. 



