74 MANUAL OF HUMAN PROTOZOA 



posterior end, is a blepharoplast, a small granule, in which 

 originates a flagellum. The flagellum runs forward along 

 the outer border of the undulating membrane which is a 

 somewhat spiral thin expansion of the pellicle and which 

 arises near the blepharoplast and extends to the anterior 

 end. The active waving movements of the undulating mem- 





Fig. 17. Trypanosoma gambiense in a stained blood smear of an inocu- 

 lated rat. Two individuals are in the process of division. X 1150. 

 (original) 



brane aid the organism in moving about in the blood 

 plasma. The flagellum extends beyond the membrane at 

 the anterior end and becomes a free flagellum. The bodv 

 is 15-30m long by l-3p broad. Some are long and slender, 

 others short and broad. Between these extremes are found 

 intermediate forms. The long forms are those in which 

 binary fission is taking place, while the short individuals 

 are thought to be recently divided forms. 



Thick and thin smears of peripheral blood (p. 97) should 

 be examined. In the majoritv of cases, the trypanosome is 

 very scanty and may not be found until after several smears 

 have been examined. Some advocate the examination of 



