742 



PATHOGENIC PROTOZOA 



nucleus placed in front of or close beside the trophonucleus and by 

 having a rudimentary undulating membrane. 



Cultivation. In 1903, Novy and MacNeal 1 first obtained pure cul- 

 tures of trypanosomes on artificial media. The medium devise^ by 

 them is prepared by equal parts of nutrient agar and defibrinated rab- 

 bit blood. After the agar has been melted and cooled to about 50 C. 

 an equal quantity of rabbit blood is added, mixed and allowed to cool. 

 "The tubes thus prepared are allowed to set in an inclined position, 

 after which they are at once inoculated. It is essential that the sur- 

 face of the medium be moist and soft, and if this is not the case, the 

 tubes should be placed in an upright position until some water of 

 condensation accumulates at the bottom. The initial 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 Eana esculenta, 

 Rana temporaries and Hyla 

 arborea; the organisms 

 are, however, not very nu- 

 merous in any single frog. 

 It is most often found dur- 

 ing the spring and summer 

 months, rarely in winter. 

 Morphology. Both 

 body and undulating mem- 

 brane are broad, the cyto- 

 plasm is granular, and to- 

 ward the straight side 



shows striae, probably indicating the presence of myonemes. The tro- 

 phonucleus is 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 kinetonu- 

 cleus turns forward, forming the border of the undulating membrane, 



sro/t 



FIG. 168. TRYPANOSOMA ROTATORIUM IN BLOOD 

 OF FROG. (After MacNeal, "Pathogenic Micro- 

 organisms," published by P. Blakiston's Sons 

 & Co.) 



1 Novy and MacNeal, Contrib. Med. Research (Vaughan), Ann Arbor, 1903, 

 p. 549. 



