PROTOZOA IN THE CIRCULATORY SYSTEM 77 



The trypanosome as seen in a stained smear of the 

 peripheral ]:)l()()d, is a curved (in the form of the letter 

 C or U) spindle-shaped organism with a sharply pointed 

 posterior end, near which a conspicuously large ovoid 

 blepharoplast is present (Fig. 19, 1). The organism measures 



^Pk^ 



2 



i 





i 

 / 



Fig. 19. Trypanosoma cruzi. X 1150. (original) 



1. Fi\'e trypanosomes seen in a very thin stained blood film 



of an inoculated rat. 



2. Leishmania forms found in skeletal muscle cells of a 



patient. 



3. Flagellating individuals seen in a host cell. 



about 20|j in length. The nucleus is located in the middle 

 of the body. The undulating membrane is narrow and only 

 slightly convoluted. Both slender and short-broad forms 

 occur. Dividing forms are usually not found in the human 

 blood. 



The trypanosome enters the tissue cell: muscles, central 

 nervous system, bone marrow, lungs, th\roid, etc., and 

 transforms into an ovoid bodv, the leishmania form (Fig. 

 19, 2)^ by discarding the flagellum and undulating mem- 

 brane. Here, it undergoes repeated binary fission, and 

 increases in number. The host cell becomes distended. 



