1078 PATHOGENIC PROTOZOA 



culture usually requires a week or more, although not infrequently 

 fairly rich growths may be obtained in three or four days" (Novy). 



Trypanosoma rotatorium. Gruby described and named this 

 hemoflagellate in 1843, and it is, therefore, the type species of the 

 genus. The organism is widely distributed throughout the world, 

 and is found in Rana esculenta, Rana temporaria and Hyla arborea: 

 the organisms are, however, not very numerous in any single frog. 

 It is most often found during the spring and summer months, rarely 

 in winter. 



Morphology. Both body and undulating membrane are broad, 

 the cytoplasm is granular, and toward the straight side shows striae, 

 probably indicating the presence of myonemes. The trophonucleus 



FIG. 134. TRYPANOSOMA ROTATORIUM IN BLOOD OF FROG. (After MacNeal 

 "Pathogenic Microorganisms," published by P. Blakiston's Son & Co.) 



(s large, lies near the middle, of the body and near the undulating 

 membrane; the kinetonucleus is smaller, lies posteriorly and stains 

 deeply; the flagellum which originates near the kinetonucleus turns 

 forward, forming the border of the undulating membrane, and is 

 continued forward as a short flagellum. The posterior end is usually 

 drawn out to a stubby point. The fully developed organism is large, 

 being 40 to 80 microns long by 5 to 40 wide. One striking thing 

 about this parasite is its tendency to pleomorphism. 



Multiplication in the blood stream of the frog is by binary fission ; 

 in addition, a form of multiple division occurs in the viscera, pre- 

 ceded, according to Machado, by conjugation of sexually differen- 

 tiated forms. The merozoites liberated from the mother cell are 

 small trypanosomes, which in turn grow to large size, thus explaining 

 the pleomorphism of the parasite. 



