SPIROCHETE GROUP 451 



Spirochxta pallida 



Synonyms. Spirillum pallidum; Treponema pallidum. 



Disease Produced. Syphilis in man. 



Schaudinn and Hoffmann, in 1905, described the organism which 

 is now generally accepted as the cause of syphilis. Prior to that 

 date many organisms had been described as possible causes, 

 but all are now known either to be secondary invaders or commen- 

 sals. 



Distribution. The disease is widely distributed among all 

 civilized peoples. 



Morphology and Staining. The Spirochceta pallida is a slender 

 organism, less than 0.5 ^ in diameter and 4 to 20 ^ in length. 



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JM j 



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Fig. 199. SpirochcBta pallida in the lumen of a bronchus in congenital syphilis 



(Hedren). 



The spirals are quite regular, and vary in number from three to 

 forty. A flagellum has been detected at each pole. The organism 

 is actively motile. Multiplication is probably by transverse 

 division, although longitudinal division is said to occur. The 

 organism is so slender, and stains with such difficulty, that there 



