188 MICRO-ORGANISMS AND DISEASE. [CH. xin. 



or both ends. Warming occasionally saw two and three 

 flagella at one end. It is about 0*003 mm. thick ; all 

 forms occur between such as have half and such as 

 have two and a half turns of a spiral. Lankester also 

 saw the same kind of organism amongst his peach-coloured 

 bacteria. 1 



3. Pathogenic spirilla. 



Spirillum Obermeyeri (of relapsing fever) is morphologically 

 identical with spirillum tenue (or spirochaeta plicatilis of 

 Cohn). It was discovered in great numbers by Obermeyer 2 

 in the blood of the general circulation in patients suffering 

 from relapsing fever. The 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. 3 H. V. Carter 4 

 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 artificially 

 the spirilla Obermeyeri, and saw them growing into long 

 spiral threads. 5 



1 Quarterly Journ. of Micr. Science, vol. xiii. New Series. 



2 Centralb. f. med. Wiss. IO, 1873. 



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



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



5 Deutsche med. Woch. 19, 1879. 



