DIFFERENTIATION FROM OTHER SPIROCELETES 735 



would appear to be identical with the Spirochceta refringens, from which it 

 is distinguished only by minor differences in the arrangement of the turns of 

 the spirals. It occasionally has two flagella, attached, as in the case of 

 Spirochceta refringens, to the rounded end of the parasite. This is probably 

 the organism which Levaditi succeeded in growing symbiotically with certain 

 anaerobic organisms in collodion sacs filled with heated human serum in 

 the peritoneal cavity of a rabbit. 



C. Spirochseta plicatilis. This is a large, thick spirochsete which stains 

 easily. The undulations are widely separated and of large amplitude. It 

 has a large undulatory membrane but no flagellum. 



D. Spirochaeta dentium. This spirochsete which multiplies in carious 

 teeth (Koch, Miiller), more closely resembles the Treponema pallidum than 

 any other species (Levaditi). 



In common with the Treponema pallidum it is an organism of very delicate 

 structure only slightly refractile in the fresh condition, and the turns of the 

 spiral are regular and permanent. It is, however, shorter than the Treponema, 

 its average length being 4 10/u, and the turns of the spiral are closer together 

 and not so deep. It stains more easily than the spirochsete of syphilis. 

 Miihlens and Hartmann have been able to grow it outside the body. 



FIG. 350. Various spirochaetes. A, Treponema pallidum : B, S. refringens : C, Spirochsete 

 from a cancer : D, S. plicatilis : E, S. dentium : F. S. vincenti. 



Miihlens grew it in Veillon's tubes containing a mixture of two parts of liquefied 

 agar and one part of horse serum heated to 58-60 C. for half an hour. The serum- 

 agar was sown at 40 C. and the tubes rapidly cooled. After incubating at 37 C. 

 for 8 days very small, whitish, transparent, snow-like colonies were seen in the 

 depth of the agar. It was possible to 'sow a series of sub-cultures. The cultures 

 were not pathogenic. The spirochsetes occasionally had a long, fine, terminal 

 flagellum but often no flagellum at all could be seen. No undulatory membrane 

 was found. In two of the cultures longitudinal multiplication forms having the 

 form of a Y or a V were observed. 



E. Spirochseta buccalis. The Spirochceta buccalis was described by Cohn 

 as occurring in the human mouth ; it is a large spirochsete ; the undulations 

 are few in number and of wide amplitude : it stains easily, and has one or 

 two flagella arranged like those of the Spirochceta refringens. The undulatory 

 membrane which has sometimes been described in connexion with it would 

 appear to be formed by the debris of the periplast. There should be little or 

 no difficulty in distinguishing between this spirochsete and the Treponema 

 pallidum. 



F. Spirochaeta vincenti. This spirochsete, found in association with fusiform 

 spirilla (p. 574), has the same characters as the Spirochceta buccalis. It must 

 be regarded as either very closely related to or identical with that organism 

 (Spirochceta media Prowazek). 



G. The Spirochsetse of malignant ulcers. In malignant ulcers, Lcewenthal 



