254 THE PATHOGENIC FLAGELLATES 



in herpetomonas, but in other cases, and apparently in the best authen- 

 ticated cases, the flagella are always formed by newgrowth from the 

 basal body. 



The flagella are always accompanied by a protoplasmic membrane, 

 to which they (are attached as a lateral cord. This membrane, if 

 drawn out straight, is often longer than the body whence it is attached 

 in folds or undulations, while by its movements, directed by the 

 attached flagellum, the organism moves through a liquid medium 

 with a peculiar auger-like movement, and gave the reason for Gruby's 

 name, trypanosoma. In the majority of forms the flagellum is con- 

 tinued beyond this membrane as a free "whip" in the surrounding 

 medium, l3ut in other cases, as in Tryp. dimorphon, it terminates with 

 the membrane. 



As to the minutiae of flagellum and membrane formation the best 

 and most complete account has been given by Schaudinn in the case 

 of Tryp. noctuoe, the blood parasite of the little owl Glaucidium noduoe. 

 The kinetonucleus divides by heteropolar mitosis, the smaller part 

 becoming the blepharoplast, the larger remaining as the kinetonu- 

 cleus. The smaller then divides again and a spindle figure is formed 

 which, except that it is heteropolar, resembles that of free flagellates, 

 having a central spindle formed by the division centre, and eight 

 "mantle fibers" corresponding to the chromosomes. The central 

 spindle forms the flagellum at the edge of the undulating membrane 

 which now grows out from the anterior end of the organism, while 

 the eight fibers form the myonemes of this membrane (Fig. 99, p. 247). 

 There is reason to believe that if this account of the formation of the 

 membrane is accurate, the so-called chromatin of the kinetonucleus 

 is in reality kinetic substance. Schaudinn's figures were acknowl- 

 edged by himself to be schematic, and it is quite probable that the 

 formation of flagellum and membrane does not follow such a clean- 

 cut scheme ; it illustrates the fact of widespread occurrence, however, 

 that the flagellum does not emerge from the kinetonucleus direct. A 

 similar granule is formed from the division centre of the kinetonucleus 

 (Prowazek, 1905) of Tryp. lewisi, and the flagellum is held by 

 Prowazek to arise in the same way as in Tryp. noduoe, while the 

 mantle fibers become eight longitudinal but ill-defined lines running 

 the length of the cell. Similar myonemes were observed by Prowazek 

 in Tryp. brucei, while Dutton, Todd, and Tobey ('07) found striations 

 (myonemes) in every trypanosome examined by them in Africa; 

 neither Moore and Breinl nor Minchin could find myonemes in Tryp. 

 gamhiense, although the basal granules (which Moore and Breinl 

 laboriously call the "bead," in order to save their very strained nomen- 

 clature) are found. Eight myonemes, furthermore, were found by 

 Keysselitz ('OG) in Trypanoplasma borreli. It is quite probable, 

 therefore, that the ectoplasm of a trypanosome cell is provided with 

 myonemes or elementary muscular fibers of kinetoplasm. 



