70 SPIROCH,ETES. 



latter (as this name was already occupied) Treponema. 

 The characteristics of this genus were: The round 

 shape of the body in section, as opposed to the flattened 

 shape of the spirochaetes ; the fixity of the curls exhib- 

 ited by the organism; the absence of an undulating 

 membrane; and the presence of terminal filaments. 

 Sp. pertenuis, from its close resemblance to Sp. pallida, 

 was afterward placed in the same genus. 



Examination of the qualities on which this distinc- 

 tion is founded does not tend to strengthen a belief in 

 its validity. The round shape of the organism in section 

 may be admitted, but the ribbon-like shape of the other 

 small spirochaetes is not very clearly established. The 

 existence of an undulating membrane is doubtful even 

 in the larger spirochaetes, and still more problematical 

 in the smaller group. Terminal filaments may be found 

 in other species besides Sp. pallida; and finally the even 

 curls presented by this spirochaete may at times be ab- 

 sent, as is admitted even by Schaudinn himself. Nor- 

 ris, Pappenheimer and Flournoy point out that the Sp. 

 obermeieri exhibits all the characteristics assigned to a 

 treponema. 



Blanchard gives the following classification : 

 A. SPIRO BACTERIA. Cohn, 1875 (Spirillaceae, Mi- 

 gula, 1890). Curved bacteria; rigid; exhibiting trans- 

 verse division. 



1. Spirosoma, Migula, 1900. Curved rigid rod; no 

 flagella. (Sp. nasale, Wibel, 1887. Sp. linguale, 

 id., 1888.) 



2. Vibrio, Ehrenberg, 1878. (Microspira, Schrotter, 

 1886.) Rigid, flagellated rods, joined end to end, 

 no spores. (V. cholera, etc.) 



3. Spirobacillus, Metchnikoff, 1889. Large spiral 

 bacteria; lateral flagella; spores. 



