No. 498] 



THE SPIROCHETES 



377 



Trypanosomid.e Doflein 1901 

 Flagellates twisted into a spiral, the coils being more 

 or less numerous. Organisms flexible, with form more or 

 less fixed, multiplying by longitudinal division. Xo 

 endogenous spores. Locomotive apparatus consisting 

 either simply of an undulating membrane, or of such a 

 membrane together with one or two flagella. Xot stained 

 by Gram's method, not cultivated in the media used in 

 bacteriology. 



Four genera: Spiroclucta, Treponema, Trypanosoma, 

 Trifpanoplasma. 



The first two genera are very similar and include the 

 only forms concerning the animal nature of which there 

 is any question. It will be necessary to consider these 

 somewhat closely. The first is characterized thus: 



SpirochjETa 1 Ehrenberg 1833 

 Body excessively slender, spiral, flattened, ectoplasm 

 extending in a narrow undulating membrane which sur- 

 rounds in a spiral the entire body. Xo flagella, no 

 endogenous spores. Nucleus greatly elongated, filiform, 

 in the axis of the body, with chromatin granules dis- 

 tributed along its surface. Reproduction in all proba- 

 bility by longitudinal division. None of the media used 

 in bacteriology serve to maintain cultures of these organ- 

 isms. Type species, 8. plicatUis. 



All these forms are by some students assigned to the 

 bacteria.' Some species are inhabitants of stagnant 

 waters, others live in the sea or in decaying organic 

 materials, while still others are parasitic. Among the 

 latter are forms recently recognized as the cause of most 

 virulent infective diseases in man and other animals. 

 The genus characters given above are not in their original 

 form, but as emended by Blanchard, and this emendation 

 becomes now the basis of the group thus named. The 



