CHAPTER XXXVI 

 THE SPIROCHETES 



HIDEYO NOGUCm 



Rockefeller Institute for Medical Research, New York City 



CLASSIFICATION 



Under the name Spirochaeta a large number of micro-organisms has been de- 

 scribed, including the variety of free-living spiral forms found in stagnant water, 

 cesspools, and damp soil; the large, actively motile spiral organisms with frilled mem- 

 branes which live in the crystalline styles of certain sheMsh; the minute spiral in- 

 habitants of the normal mouth, genitalia, and intestinal tract of mammals; and, 

 finally, a considerable group of pathogenic micro-organisms, all rather minute, but 

 varying in morphology, which are found in the blood or tissues in certain diseased 

 conditions of man and of animals. All these micro-organisms, notwithstanding their 

 diversity of form, are often indiscriminately referred to as "Spirochaeta," although 

 this genus was created by Ehrenberg' in 1833 for a saprophytic spiral micro-organism 

 (wnrmfdrmiges Schlingentierchen) which he found in the spring of 1832 in some water 

 which had been kept in his house in Berlin through the winter. Recently, however, 

 the problem of the classification of the spirochetes has been taken up by a number of 

 workers with the result that the subject has been considerably clarified. 



It is now recognized^ that the term Spirochaeta (airelpa, "coil"; xo-lrri, "hair") 

 should be reserved for the large free-living species of the type described by Ehrenberg 

 as Spirochaeta plicatUis (Fig. i).^ A characteristic axial filament, about which the cell 

 body is spirally wound, has been described for this species, first by Schaudinn (Fig. 

 4),-' and more recently by Zuelzer (Figs. 2-3). s Such a structure cannot be dem- 

 onstrated in other types of spirochetes, perhaps because of their small size, as Zuelzer 

 maintains, but perhaps also because it is not present in any other type. The writer 

 has attempted to demonstrate it in a Spirochaeta present in the slime of icebox 

 drains (Figs. 5-10), but without success. Zuelzer maintains that the straight axial 

 filament is the characteristic structure of all true spirochetes. She retains all trepo- 

 nemas and leptospiras in the genus Spirochaeta because she assumes the existence 

 of such a structure in these forms, although it cannot be demonstrated, and excludes 

 the cristispiras from the category of spirochetes because they definitely lack the axial 

 filament. Zuelzer holds this viewpoint almost alone, however, most workers pre- 



' Ehrenberg, C. C: Abhandl. d. Akcul. d. Wiss. zu Berlin, iSjj, p. 313. 1834; Die Infitsions- 

 lierchen. 1838. 



^ Bergey, D. H., el a!.: Manual of Delerminalive Bacteriology. Baltimore, 1925; Buchanan, R. E.: 

 General Syslemaiic Bacteriology. Baltimore, 1925; Wenyon, C. M.: Protozoology. 1926; Stitt, E. R.: 

 Practical Bacteriology, Blood Work, Parasitology (8th ed.). Pliila(lfl[)hia, 1927. 



3 The figures for this chapter follow p. 497. 



■I Schaudinn, F.: Arbcitcn. Lei[)zig and lierlin: \'oss, 1911. 



s Zuelzer, M.: Pro'wazck's Ilandb. d. path. Prolozocn, 3, 1628. 1923. 



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