676 MICROBIOLOGY OF THE DISEASES OF MAN AND ANIMALS. 



SLEEPING SICKNESS. 

 Trypanosoma gambiense. 



Sleeping sickness is a disease of man caused by Trypanosoma gam- 

 biense; it is usually transmitted by the bites of Glossina palpalis, a tsetse fly. 



Sleeping sickness only occurs in those parts of Africa where the fly 

 which transmits it exists. 



FIG. 123. Trypanosoma granulosum. n, nucleus; m, undulating membrane; c, 

 kinetonucleus;/, flagellum. X2Ooo diam. (After Laver an and Mesnil from Doftein.) 



Trypanosoma gambiense (Fig. 124) is cigar-shaped; it measures about 17/1 to 25^ 

 from the posterior extremity to the tip of its flagellum. A large main nucleus is placed 

 near the center of the trypanosome; a smaller, kinetonucleus lies near its posterior end. 

 From this smaller nucleus a filament arises, which runs the whole length of the 

 parasite and extends from its anterior end as a free flagellum. Where the filament 



FIG. 124. Trypanosoma gambiense. (After M inchin, from Doftein.) 



runs along the body, the ectoplasm is folded over it to form the undulating membrane. 

 The trypanosome moves by means of the undulating membrane and flagellum and also 

 through the contraction of myoneme fibers which lie in the ectoplasm. In the blood, 

 Trypanosoma gambiense multiplies by binary division. It is not impossible that it may 



