126 



THE RISE OF ANIMAL LIFE 



leishmonia 

 staqe ottackinq 

 cell 



"o/ flaqellate staqe 



Fig. 7-19. Life cycle of a \.Biihmania causing kala azar. 



common method of prevention is the de- found that sleeping sickness, common 



struction of the breeding places of the fly among the populations of certain parts of 



as well as the fly itself. equatorial Africa, was also caused by a try- 



A trypanosome is the cause of nagana, panosome. The fact that the tsetse fly car- 



a disease of domestic animals. It has been ried the infection was long known, even 



TSETSL fLV 



