ON CEISTISriHA VKNEKIS NOV. SPEC. 535 



organism, the org-anisiiis of i-elapsing fevers, etc. — differ not 

 a little from Cristispira and Spir ocliajta. In the forms 

 which I have been able to study myself,^ I have never been 

 able to make out any definite structure — chiefly on account of 

 their very small size. I believe that no protoplasmic structure 

 similar to that of either S. plicatilis or Cristispira is 

 visible. I also i-egard it as exceedingly doubtful that a crista 

 is present. The method of division is, I believe, in all 

 probability always transverse. Although the f ac ies of these 

 organisms is very similar to that of Cristispirje, I think it 

 is advisable to keep the two groups of organisms in separate 

 genera for the present. 



Regarding the generic name wliich must be applied to these 

 organisms, it is obvious that as neither Spirochteta nor 

 Cristispira can be used, some other name must be selected. 

 The name Spironema, proposed by Yuillemin (1905) forthe 

 syphilis organism, is pre-occupied — having been used by Klebs 

 for a flagellate. Schaudinn (1905a) therefore proposed the 

 name Treponema — a name which must stand, according to 

 the rules of nomenclature. If it l)e allowed, that the small 

 parasitic Spirochrets are similar to the syphilis organism,- it 

 therefore follows that they must all be placed in the genus 

 Treponema. It appears to me advisable to adopt this 

 system. 



For the three groups of organisms which are included in 

 the common name '" Spirochtets " there are therefore three 

 generic names already in existence. On the assumption, then, 

 that these three groups are sufficiently akin to one another to 

 justify their being collected into a common class — an assump- 

 tion Avhich appears to me to be justified in our present state of 

 knowledge — I propose to classify the Spirocluets as follows : 



' These are especially forms from the gut of the frog aud toad 

 (Dobell, 1908), from termites (Dobell, 1910). and "S." buccalis and 

 " S." dentinm (unpublished observations). 



^ I see no vaHd reason for drawing a generic distinction l>et\veen 

 Treponema pallidum and such forms as '■ Spirocha-ta " recnr- 

 rentis, '" S." duttoni. " S.'' dentium, etc. 



