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THE AMERICAN N AT 'V BALI ST [Vol. XLII 



considered very briefi\- also certain clearly bacterial forms 

 (Spirosoma, Vibrio, Spirobacillus) and others distinctly 

 flagellate (Trypanosoma, Trypanoplasma) which in his 

 opinion manifest close relationship to the true spiral 

 microorganisms of which he recognized three well- 

 founded genera, Spirilla in, Spirochccta and Treponema. 

 The group of plant organisms he classed as follows: 



Spirobacteria Cohn 1875 



Bacteria more or less curved in a spiral, the curve form- 

 ing at times only the arc of a circle, in other cases form- 

 ing spiral coils more or less numerous. Organisms little 

 flexible or not at all, multiplying by transverse division. 

 Formation of endogenous spores demonstrated in a num- 

 ber of species. 



Four genera: Spirosoma, Vibrio, Spi robacillus, Spiril- 

 lum. 



Of the last genus he says: Spirillum Ehrenberg 1830— 

 Body spiral, cylindrical in transsection, not tapering at 

 the ends. Xo undulating menihrane. One or several 

 flagella bent in a regular curve, either at both extremities 

 or at one only. Formation of endogenous spores demon- 

 strated in a number of species. Organisms relatively of 

 considerable size, cultivated easily on various media used 

 in bacteriology. 



The spirilla are clearly bacteria. They live as sapro- 

 phytes in wells, stagnant waters, the soil, liquid manure, 

 etc., and generally in media very poorly oxygenated. 

 Possibly one should include in this genus some forms 

 which are found in pus, but it is doubtful if these play an 

 active part in it, and up to the present time not a single 

 species can be considered as surelv pathogenic. 



Over against these forms, and sharply contrasted with 

 them Blanchard placed the animal organisms of a general 

 spiral form. These he included in a single family, char- 

 acterized tlms: 



