HIDEYO NOGUCHI ^,53 



ferring to classify the organisms on the basis of recognizable morphological dilTer- 

 ences. 



The spirochetes of shellfish were placed by Gross' in a new genus, Cristipira, be- 

 cause of the membranous appendage wound about the body; and another genus, 

 Saprospira, was created by Gross for a type which resembles Cristispira in size and 

 structure, but lacks the membrane. 



Opinions still differ somewhat as to whether the parasites of syphilis and those 

 of relapsing fever and smegma should be placed in a single genus or separated. Schau- 

 dinn^ pointed out that the syphilis organism differs from the saprophytic inhabitant 

 of the smegma, to which he gave the species name refringens, in the rigidity of its 

 spirals. But under cultural conditions, as the writer observed in 1913,^ the only dif- 

 ference actually existing between the two organisms is in staining property, the 

 refringens having more plasmatic substance and therefore taking stains more readily. 

 Some writers still treat the organisms which cause relapsing fever as a species dis- 

 tinct from the treponemas because they possess certain characteristic biological and 

 cultural properties. Morphologically, however, the parasites differ from the syphilis 

 organism in the same way as does the refringens, but in greater degree, i.e., they have 

 considerably more plasmatic substance. They were first separated from the trepo- 

 nemas by Swellengrebel,-' who thought that they all possessed peritrichal flagella.^ 

 The publication of Swellengrebel in which he suggested the generic designation of 

 Borrelia for the relapsing-fever group antedated by four months that of Sambon^ in 

 which Spiroschaudinnia was suggested; hence, if we regard the group as distinct, we 

 are bound to adopt the name Borrelia, irrespective of the morphological assumption 

 upon which it was based, with anserinuni as the type species instead of recurrentis. 

 The writer, in 1918,' used the name Spironema, which had been adopted by Gonder;^ 

 but, as has been pointed out,' Spironema was unavailable because preoccupied, and 

 both Borrelia and Spiroschaudinnia have priority. On morphological grounds the 

 separation of the group is not desirable, since the variation between recurrentis and 

 refringens is hardly greater than that between refringens and pallidum and is only a 

 matter of the thickness of the protoplasmic coat. On the whole, it seems best to re- 

 gard the two groups as one and retain the appropriate generic name of Treponema. 



The cause of rat-bite fever (Fig. 128) is more closely affiliated with the Spirilla 

 as are also certain spiral organisms found in the stomach of the dog (Fig. 129) cat, 

 and other animals.'" These may be placed in a separate group under Spirella, as first 

 suggested by Duboscq and Lebailly." 



' Gross, J.: Mill. a. d. zool. Station zu Ncapcl, 20, 41. igio. 



^ Schaudinn, F.: loc. cit. ' Noguchi, H.: Prcsse nied., 21, 801. 1913. 



''Swellengrebel, N. H.: Ann. deVInst. Paslciir, 21, 562. 1907. 



s Borrel, A.: Coiiipl. rend. Soc. de hioL, 60, 138. 1906. 



*" Sambon, L.: Biil. M. /., 2, 1323. 1907. 



7 Noguchi, H.: /. Exper. Med., 27, 575. 191S. 



* Gonder, R.: Prowazck's llandb. d. path. Prolozocn, 6, 671. 1900. 



'Buchanan, R. E.: loc. cit.; Stitt, E. R.: loc. cil. 



'"Regaud, C: Compt. rend. Soc. de bloL, 66, 617. 1909. 



" Duboscq, O., and Lebailly, Ch.: Compt. rend. Acad, dcs Sci., 154, 835. 1912. 



