I2 4 



THE ANIMAL PARASITES OF MAN 



was usual here. Maximum growth occurred in the culture about the 

 fifth day. 



TREPONEMATA. 



The genus Treponema (Schaudinn, 1905), includes minute, thread- 

 like organisms, with spirally coiled bodies, the spirals being preformed 

 or fixed. No membrane or crista is present, according to Schaudinn, 

 though a slight one is said by Blanchard to be present in the organism 

 of yaws. The ends of the organisms are tapering and pointed. 

 Multiplication is by longitudinal and transverse division. The most 

 important members of the genus are T. pallidum, the agent of syphilis, 

 and T. pertenue, which is responsible for frambcesia or yaws. 



Treponema pallidum, Schaudinn, 1905. 

 Syn. : Spirochceta pallida. 



Treponema pallidum was first described by Schaudinn and Hoff- 

 mann in 1905 under the name of Spirochceta pallida. It has also been 



described under the names 

 ofSpironema pallida, Micro- 

 spironema pallida and 

 Trypatiosoma hits. Siegel 

 in 1905 described an organ- 

 ism which he called Cyto- 

 rh\ctcs lu is and considered 

 to be the agent of syphilis. 

 Schaudinn reinvestigated 

 Siegel's work and found 

 T. pallidum, which he con- 

 sidered to be the causal 

 agent of the disease, and 

 pronounced against Cyto- 

 rhvctes hits. It is probable 

 now that both workers 



FIG. &. Trepa*uma pallidum. (After Bell, from were Correct, for Balfour 



Castellani and Chalmers.) 



( I 9 11 ) na S Seen the 



sion of minute granules 



or " coccoid " bodies from 7\ pallidum and these granules probably 

 correspond to the C. luis of Siegel. Recently E. H. Ross, having 

 observed a spirocha3te stage in the development of Kurloff bodies, 

 thinks that 7. pallidum is a stage in the life-history of a Lympho- 

 cytozoon. MacDonagh has also described a complicated and some- 

 what similar cycle, but these observations require further study and 

 confirmation. 



T. pallidum varies from 4/4 to 10/1, in length, its average length 

 being 7/4, while its width is usually about 0^25 p. Longer individuals 



