HIDEYO NOGUCHI 487 



Angerer,' who seems to have been the first to obtain pure cultures, used Haen mem- 

 brane filters (pores 1.5 m)- None of the pure cultures so far obtained has been patho- 

 genic for animals or serologically related to L. icterohaemorrhagiae. Some strains have 

 a slight group reaction with L. hebdomadis. There is undoubtedly more than one 

 distinct strain of leptospira in water. The strain isolated in the writer's laboratory 

 is distinctly larger than any pathogenic leptospira which we know, but in the icebox 

 slime from which this strain was cultivated there seem to be at least two other types: 

 one very fine and short (Fig. 124), and one of medium size which is similar to L. heb- 

 domadis or L. icterohaemorrhagiae (Fig. 125). Apparently the large type (Fig. 126) 

 is the more readily cultivated. The slime seems to offer ideal conditions for the 

 growth of the organisms, providing it has a neutral or slightly alkaline reaction. 



Various names have been proposed for the water leptospiras, Leptospira bijlexa 

 (Wolbach and Binger, 1914), L. pseudoicterocenes (Uhlenhuth and Zuelzer, 1922), 

 L. aquatilis (Hoffmann). It is not yet known whether or not each of these represents 

 a separate species. 



Saprophytic leptospiras have been found in the human mouth by Erich Hoff- 

 mann,^ who called them L. trimerodonta. Perrin^ found in an inflammatory bucco- 

 maxillary lesion a leptospira to which he gave the name L. dentate. The writer^ 

 found a very small leptospira in the stomach of the ox (L. bovis [Fig. 127]). 



L. icterohaemorrhagiae (Fig. 12 j). — L. icterohaemorrhagiae, which causes Weil's 

 disease in man and "yellows" in dogs, was discovered by Inada and Ido,^ who first 

 found it in the blood, liver, and kidneys of young guinea pigs which had died of 

 hemorrhagic jaundice as a result of the inoculation of the blood of patients with 

 Weil's disease in Japan. About a year later Hiibener and Reiter,'' working independ- 

 ently in Germany, found a similar spirochete in guinea pigs inoculated with patients' 

 blood, and subsequent investigations showed that the micro-organism is distributed 

 throughout the world. It is rarely seen in the blood during life,' being demonstrated, 

 as a rule, only by inoculation of guinea pigs or implantation on suitable culture me- 

 dium. During convalescence it is present in the urine over a long period and can 

 readily be recovered by passage through guinea pigs to eliminate associated bac- 

 teria. It is readily found postmortem in various tissues, especially in the liver and 

 kidneys. 



The severity of the infection with L. icterohaemorrhagiae in man varies in differ- 

 ent localities, owing no doubt to difference in the virulence of the strains and in indi- 

 vidual susceptibility. The disease is often extremely severe in Egypt* and parts of 

 Asia Minor, and is clinically very much like yellow fever. In Japan the mortality 

 is as high as 30 per cent, and there also the disease has been confused with yellow 



' Angerer, K. v.: loc. cil. iNoguchi, H.: New Yorli State M. J., 22, 426. 1922. 



2 Hoilmann, E.: loc. cil. s Inada, R., and Ido, K.: loc. cil. 



3 Perrin, T. G.: loc. cil. ^Hiibener and Reiter: loc. cit. 

 'Inada, R., Ido, Y., Hoki, R., Kaneko, R., and Ito, H.: loc. cit. 



* Valassopoulo, A.: Prem. Cong. Egyp. de vied., i, 167. 1904; Kartulis: "A Discussion on Cases 

 of Jaundice in the Military Hospitals at Alexandria," Med. Serv., Mediterranean Exped. Force. 

 Alexandria, 1915. 



