357 



Spirochaeta Pallida (Treponema Pallidum). Schaudinn and 

 Hoffmann in 1905 observed this slender spiral organism in pri- 

 mary syphilitic lesions, in fluid obtained from swollen lymph 

 glands in syphilis and in the liver and spleen of a still-born syphi- 

 litic fetus. The occurrence of the 

 organism in syphilitic lesions was 

 quickly and abundantly confirmed 

 by other workers. Cultures were 

 first obtained in collodion sacs by 

 Levaditi and Mclntosh in 1907. 

 Schereschewsky, and Muhlens and 

 Hoffmann obtained cultures in gela- 

 tinized horse serum. Noguchi 1 has 

 carried out the most successful cul- 

 tural work and has succeeded for 

 the first time in causing syphilitic 

 lesions in animals by the inocula- 

 tion of pure cultures. 



Sp. pallida occurs naturally only 

 in human syphilis. It is a slender 

 spiral 0.2 to 0.3 5 n in thickness and 

 3.5 to 1 5. 5 /z in length. Its curves 

 are narrow and very regular. It is 



! ,., ,, . FIG. 142. Film preparation 



actively motile, as are all the spiro- from a gen ital syphilitic papule; in 

 chetes, and has a very slender fla- e . ce . nter ar f 7 ^ wo specimens of 



; Sptrochata pallida, the other three 



gellum at each end. The Usual mo- are specimens of Spirochala refrin- 



tion is that of rapid rotation on the Schaudinn and 



longitudinal axis with progression, 



but at times there is gross bending of the filament, especially 

 when the organism is living under unfavorable conditions. 

 The mode of division is a somewhat vexed question as it 

 is in regard to the whole group of spirochetes. Transverse 

 and longitudinal division have been described. Probably 

 the weight of authority 1 now favors transverse division as 



1 Journ. Exp. Med., 1911, Vol. XIV, p. 99; 1912, Vol. XV, p. 90. 



