224 THE PATHOGENIC FLAGELLATES 



different type, Butschli ('02) finding only one case, and this not wholly 

 satisfactory, where the flagellum appeared to be prolonged into the cell 

 body of Spirillum giganteum (volutans) (Fig. 89). Swellengrebel ('07) 

 described an occasional thickening at the lower end of the flagellum of 

 this same species which he regarded as a basal granule, but as it lies 

 outside of the protoplasmic body it is more probably a local thick- 

 ening or condensation rather than a kinetic body similar to those of 

 animal flagella. Furthermore, numerous observers (Fischer, Kutscher, 

 Ellis, and others) affirm that the flagellum is not single, but consists, 

 at times at least, of a bundle or tuft of "cilia." Zettnow, Fischer, and 

 Butschli give evidence to show that the flagellum arises as a prolonga- 

 tion of the periplast, the latter, with Ellis and Swellengrebel ('07), 

 showing that it comes from an apical thickening (calotte) of the 

 periplast. 



In the spirillum group the flagellum thus appears to arise from the 

 enveloping periplast, and is not, as in protozoa, of endoplasmic origin. 

 In spirocheta the conditions have recently been carefully studied by 

 Siebert ('OS), who finds that the so-called flagellum of different forms 

 arises in the same manner as in the spirillacese, and is morphologically 

 different from the flagella of mastigophora. As processes of the peri- 

 plast arising as the attenuated ends after division of the cells, e. g., 

 in Sy. recuTrentis (Sp. obermeieri), the flagella have an entirely dif- 

 ferent significance from those of the monads and other mastigophora. 

 Furthermore, the rare occurrence of "ciliated" forms — sometimes 

 double (Schaudinn), sometimes single and variously placed (Levaditi) 

 — of Treponema pallidum, or of Sp. microgyrata, may be interpreted, as 

 Krzysztalowicz and Siedlecki ('05-'08) assert, as the attenuated ends 

 which remain after division. 



The myonemes characteristic of the undulating membrane of Sp. 

 balbianii, indicate, however, a higher development of kinetoplasm 

 than is to be found among the bacteria, and it is reasonable to 

 assume that all spirochetes with undulating membranes have similar 

 contractile fibrils. Furthermore, the energetic movements of spiro- 

 chetes without flagella may be accounted for upon the hypothesis 

 that the periplast or membrane is similarly provided with muscular 

 elements. Siebert has shown that under the action of certain digestive 

 fluids spirochetes break up into fibrillae similar to those which have 

 been described in peritrichous forms. Borrel ('06), Zettnow ('06), 

 the former for Tr. gallinarum, the latter for Sp. duttoni, and Levaditi 

 and Mcintosh ('07), for a species of treponema similar to, if not 

 identical with, Treponema pallidum, have described so-called diffuse 

 flagella appearing at various parts of the cell, sometimes terminal, 

 sometimes lateral, while oftentimes they are multiple and irregularly 

 placed. Whatever these chance peritrichous appendages may be, 

 they are certainly not flagella in any strict morphological sense, and 



