CHAPTER XLII 



SPIROCHETE GROUP 



THERE is probably more confusion relative to the classification 

 of the members of this group of organisms than in any other 

 group of bacteria or protozoa. In the first place, there is by 

 no means an agreement among investigators as to whether 

 these organisms should be included under the heading of bacteria 

 or of protozoa. There seems to be more evidence in recent 

 literature of protozoan rather than of bacterial relationships. 

 Second, it is evident that the group is not homogeneous, and 

 efforts have been made to separate the group into several genera. 



Fig. 193. Spirochceta pinnce: A, B, Cells showing the undulating membrane; 

 C, a coiled organism (adapted from Gonder) . 



In not a single case have we a full and satisfactory knowledge of the 

 life history, particularly in those forms which are transmitted from 

 one animal to another by parasites. Until this is worked out it 

 will be impossible to make a separation of the different types into 

 genera on the basis of true relationships. In the discussion of the 

 group the genus name of Spirochoeta is retained, the first of the 

 synonyms given being the one which has been suggested by Blanch- 

 ard in his revision of the group on the basis of protozoan relation- 

 ship* 



The argument advanced for protozoan relationships may be 



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