CHAPTER XXVII. 



TREPONEMATA AND SPIROCHETA. 



TREPONEMATA. 



Treponema Pallidum. 

 Treponema Refringens. 

 Treponema Recurrentis. 

 Treponema Novyi. 

 Treponema Carter!. 



Treponema Duttoni. 

 Treponema Pertenue. 

 Treponema Phagedenis. 

 FUSIFORM BACILLI AND SPIRILLUM Fusi- 

 FORMIS. 



TREPONEMATA. 



Treponema Pallidum. Synonym. Spirocheta pallida. 



Historical. The organism which is now universally conceded to 

 be the infective agent in syphilis was first described by Schaudinn 

 and Hoffmann. 1 It was named Spirocheta pallida by these observers, 

 but it presents certain peculiarities of structure which are of sufficient 

 magnitude to separate it from the group of the spirochetes. It has 

 been placed in a newly established group, the Treponemata, of which 

 it is the type organism. 



Morphology. Treponema pallidum is a long, very thin, delicate, 

 closely coiled, flexous spiral organism which measures from 0.25 to 

 0.4 micron in diameter, and, on the average 7 to 8 microns in 

 length. The length, however, may vary from 3 microns in very young 

 organisms to 15 microns. The spirals, which are very regular in out- 

 line, are ordinarily from six to twelve in number per organism; they 

 may be as few as three to five in the shorter forms or as numerous 

 as twenty in the longer forms. 



Noguchi 2 has described three morphologically recognizable types of 

 Treponema pallidum: an average or normal type; a type thicker 

 than the average; and a type thinner than the average; each of 

 which induces somewhat different lesions in experimental animals. 

 The three types present no noteworthy cultural differences. Noguchi 

 suggests that these morphological and pathological variations observed 



1 Arb. a. d. kais. Gesamte, 1905, xxii; Deutsch. med. Wchnschr., 1905, Nos. 42-43. 



2 Jour. Exp. Med., 1912, xv, 201. 



