1922] on Microscopic Parasites and their Carriers 515 



Fig. 7. — The Trypanosome (Trypanosoma cruzi) of Chagas' Disease, and 



ITS DEVELOPMENT IN THE REDUVIID BUG (CoilOrllinUS 



(Triatoma) megistus). 

 a, b, c Development of the trypanosonie in the blood and tissues of man. 

 a, multiplication of small round forms in a muscle-fibre of the heart ; b, 

 transformation of the small round forms into trypanosomes ; c, trypano- 

 somes which have escaped from the ruptured rnuscle-flbre into the blood. 

 (a and b magnified 500 times, c magnified 1500 times.) 



p, r, s Diagram of the development in the reduviid bug. 

 s, trypanosomes in the stomach of the bug ; R, rectum containing trypano- 

 somes which are deposited on the skin, and lead to the infection of man 

 by contamination. 



d-e Development of the trypanosome in the bug. (Magnified 1500 times.) 

 D, multiplying crithidial forms ; e, trypanosome forms which produce the 

 infection in man. 



