HIDEYO NOGUCHI 485 



spirochetes may be present in the intestine of man. S. eurygyrata has been cultivated 

 (impure) by Hogue/ and Sanarelli^ has obtained pure cultures of the spirochetes 

 found in the guinea pig intestine. 



THE LEPTOSPIRA GROUP 



When Stimson, in 1907,^ described a spiral micro-organism, which he found in 

 the kidney in a case of yellow fever, and gave it the name of Spirochaeta {^) interro- 

 gans (Fig. 119), no great interest was aroused among bacteriologists, presumably be- 

 cause it did not seem likely at that time — when filterability connoted invisibility — 

 that a visible spirochete could have any etiological significance in connection with 

 a disease which had been definitely shown to be caused by a filterable virus. In 1914 

 appeared the interesting and very important article by Wolbach and Binger'' de- 

 scribing a peculiar spirochete which multiplied in the filtrate from stagnant water 

 taken from a fresh-water pond near Boston. They called the organism Spirochaeta 

 biflexa because of its characteristic hooked ends. This observation also received little 

 notice at the time. A little later (191 5) the discovery of the causative agent of Weil's 

 disease was announced by Inada and Ido,^ and also (1916) by Hiibener and Reiter'^ 

 and Uhlenhuth and Fromme.? The hooked ends which had led Stimson to call his 

 organism interrogans and Wolbach and Binger to call theirs biflexa were described as 

 one of the characteristics of the spirochete of Weil's disease, which was named Spiro- 

 chaeta icterohaemorrhagiae. The morphological and biological features of this organ- 

 ism were, in fact, so characteristic that the writer, in 191 7* was led to propose for it 

 the new genus, Leptospira (Xexr6s-|-o-7reTpa = "fine coil"). It was recognized at the 

 time, from the description given by Wolbach and Binger, that Spirochaeta biflexa was 

 probably an organism of the same type, but the proposal of the new genus was based 

 on careful study of Leptospira icterohaemorrhagiae, which was named as the type 

 species of the genus. To the genus was added, in 1919, another pathogenic species, 

 L. icteroides (Figs. 120, 121), isolated from yellow-fever patients. Subsequently (1920) 

 the writer had opportunity to study Stimson's preparations of Spirochaeta interrogans 

 and became convinced that it also was a leptospira and identical with L. icteroides. 

 Stimson's spirochete is therefore the first leptospira to be described and becomes the 

 type species of the genus (Leptospira interrogans), while Wolbach and Binger 's is the 

 first description of a free-living leptospira. 



It was not until recently that general interest was aroused in the significance of 

 free-living leptospiras, when Uhlenhuth and Zuelzer^ found, in tap water and in ponds 

 and pools in Berlin, the micro-organism which they called Spirochaeta pseudoictero- 

 genes because of its morphological similarity to Leptospira icterohaemorrhagiae (syn- 



' Hogue, M. J.: /. Expcr. Med., 36, 617. 1922. 



^ Sanarelli, G.: Ann. deVInst. Pasteur, 41, i. 1927. 



3 Stimson, A. M.: loc. cit. s Inada, R., and Tdo, K.: toe. cit. 



4 Wolbach, S. B., and Binger, C. L.: loc. oil. ^Hiibener and Reiter: loc. cit. 

 'Uhlenhuth, P., and Fromme: Ztschr. f. ImmunUdtsJorsch. u. exper. Therap., Orig., 25, 317. 



1916. 



*Noguchi, H.: J. Exper. Med., 25, 755. 1917. 



'Uhlenhuth, P., and Zuelzer, M.: Klin. Wchnschr., i, 2124. 1922. 



