HIDEYO NOGUCHI 467 



It seems possible that active leptospiras sometimes become entangled in the 

 threadlike filaments produced by degenerating organisms, for occasionally a vigorous 

 organism appears to be unable to straighten out, as if the ends were held in the bow 

 position by a thread joining them. The diminutive spirillum-like, terminal filaments 

 can hardly be of mechanical significance, since normal leptospiras move without 

 them. 



The locomotor mechanism of leptospiras is evidently more complex than that of 

 treponemas. The smooth elastic filament with its hooked ends is undoubtedly the 

 primary factor in locomotion, but the spiral form of the protoplasmic coat, with the 

 dense hyaline periplast which conforms with its windings, has an accessory function 

 in locomotion. The contractile protoplasm operates against the bowlike axis by means 

 of the brace provided by the periplast. 



FILTEEABILITY 



Novy and Knapp' were able to induce infection with filtrates of blood containing 

 T. novyi, and Breinl and Kinghorn^ obtained positive results with dultoni. Todd and 

 Wolbach^ confirmed the filterability of these blood spirochetes and were of the opinion 

 that the s{.irochetes themselves passed the filters, not granular forms of the organisms. 

 The members of the leptospira group are rather readily filterable, as Inada and Ido^ 

 and Hiibener and Reiter^ proved for L. icterohaemorrhagiae and the writer*" and 

 Dieterich^ for L. interrogans. The common leptospira of water, first described by 

 Wolbach and Binger^ as Spirochaeta bijiexa, was shown by them to be filterable, and 

 this fact has recently been utilized by Angerer,' Dimitrofif,'" Bauer," Mochtar,'^ and 

 others, as a means of obtaining pure cultures. It is interesting to recall that the virus 

 of yellow fever was proved to be filterable'^ before the discovery of any of the lepto- 

 spira group, and that Hecker and Otto'" had foretold from their investigations that 

 the virus of infectious jaundice would be a filter-passer. 



Treponema pallidum and T. pertenue are unable to pass through any bacteria- 

 proof filters by the ordinary (suction) methods. The pallidum, however, can grow 

 through the pores of Berkefeld filtrates V and N'^ and appear in the filtrate when pro- 

 vided with favorable cultural conditions. 



' Novy, F. G., and Knapp, R. E.: /. Infect. Dis., 3, 291. 1906. 



^ Breinl, A., and Kinghorn, A.: Lancet, i, 668. igo6. 



3 Todd, J. L., and Wolbach, S. B.: /. Med. Research, 25, 27. 1914. 



"t Inada, R., Ido, Y., Hoki, R., Kaneko, R., and Ito, H.: J. E.vpcr. Med., i8, 377. 1916. 



5 Hiibener and Reiter: Deutsche med. Wchnschr., 41, 1275. 1915; 42, i. 191O. 



' Noguchi, H.: /. E.xper. Med., 30, 13. 1919. 



7 Dieterich, F. H.: A»i. J. Trap. Med., 4, 553. 1924. 



* Wolbach, S. B., and Binger, C. L.: J. Med. Research, 30, 23, 1914. 



9 Angerer, K. v.: Areh.f. Ilyg., 92, 325. 1924. 



" Dimitroff, V. T.: J. Infect. Dis., 40, 50.S. 1927. 



" Bauer, J. H.: Am. J. Trap. Med., 7, 177. 1927. 



" IMochtar, A.: Universiteits Boekhandel. Amsterdam, 1927. 



'3 Reed, W., and Carroll, J. C: Senate Doc. S22 (6ist Cong., 3d Sess.), p. 149. 1911. 



■••Hecker, A., and Otto, R. W.: Veruffentl. a. d. Ge.h. d. Militdr-Sanildtsicesens, Heft 46. 1911. 



'5 Noguchi, H.: /. Exper. Med., 14, 99. 1911. 



