HIDEYO NOGUCHI 475 



ALTERATIONS IN SPIROCHETES ON PROLONGED CULTIVATION' 



The strains of T. paUidiim cultivated by the writer lost their virulence within 

 four months after their purification; T. pcrtcnuc became avirulent immediately it 

 was isolated. T. microdcntinm retained its characteristic disagreeable odor during a 

 year of cultivation, but therafter this property steadily diminished until after two 

 years it had practically disappeared. The characteristic mucin-producing property 

 of T. mucostcm likewise disappeared after a few months of cultivation. 



In the case of the leptospiras, the cultivated organisms may grow to a length of 

 40-60 fi but show no other striking differences from the naturally occurring forms. 

 Zuelzer- reports a length of 100 fx in cultures of L. icterohaemorrhagiae on donkey 

 serum. 



L. icterohaemorrhagiae and L. interrogans soon lose their virulence on cultivation, 

 but infectivity may be retained by passing the strain through guinea pigs every sec- 

 ond or third generation. 



INDIVIDUAL CHARACTERISTICS 

 THE TREPONEMA GROUP (PLATE V, PLATES IX-Xl) 



Treponema pallidum (Figs. 88-g4). — T. pallidum was first seen by Schaudinn and 

 Hoffmann^ in April, 1905, in a fresh preparation from chancre under the ordinary oil- 

 immersion objective. Because of its spiral shape and the difficulty of staining, it was 

 given the name Spirocheata pallida by its discoverers. Vuillemin,'' in June, 1905, pro- 

 posed that the name be changed to Spironema pallidum, on the ground that Spiro- 

 chaeta was a plant genus, but Spironema proved to be preoccupied, and Schaudinn,-^ 

 in December, 1905, named the organism Treponema pallidum. The generic separation 

 of the organism from Spirochaeta is desirable on morphological grounds, irrespective 

 of whether the spirochetes be regarded as plants or animals. The earlier name had, 

 however, taken such deep root in the medical literature that the organism is still 

 called by many Spirochaeta pallida. Taxonomists are rather generally agreed that the 

 correct name for the organism is Treponema pallidum. The name Spironema has been 

 used both in zoological and in botanical nomenclature,'' and hence is not valid. 



Treponema pallidum has been established as the cause of syphilis in several ways. 

 It is always present in syphilitic infections, although not always readily demonstrable, 

 and never in other conditions. The use of the dark-ground illumination for detection 

 in fresh preparations and the introduction of the Cajal-Bertarelli-Levaditi method of 

 silver impregnation for demonstrating its presence in syphilitic tissues have un- 

 doubtedly helped much in placing Treponema pallidum in its correct position. The 

 application of the Bordet-Gengou principle of complement deviation to syphilis by 

 Wassermann, Neisser, and Bruck,^ as well as by Detre,^ in 1906, was another great 



' Noguchi, H.: Ann. de I'lnst. Pasteur, 30, i. 1916. 



= Zuelzer, M.: Centralbl. f. Bakt., Orig. Beihefte, Abt. I, 85, *i4i. 1921. 



3 Schaudinn, F., and Hoffmann, E.: Arb. a. d. kaiserl. GesiDidheitsamte, 22, 527. igo5. . 



•I Vuillemin, P.: Compt. rend. Acad, de sc, 140, 1567. 1905. 



s Schaudinn, F.: Deutsche med. Wchnschr., p. 1728. 1905. 



^Buchanan, R. E.: loc. cit.; Wenyon, C. M.: loc. cit.; Stitt, E. R.: loc. cit. 



'Wassermann, A., Neisser, A., and Brack, C: Deutsche med. Wchnschr., 32, 745. 1906. 



* Detre, L.: Wien. klin. Wchnschr., 19, 6ig. 1906. 



