SLEEPING SICKNESS. 



323 



the trypanosomes of man or domestic stock might at Nawalia in 

 the Luangwa Valley be placed at 50, and at ISTgoa on the Congo 

 Zambesi watershed at 35. 



Table I. — Percentage of various species of game found infected 

 with trypanosomes pathogenic to man or domestic 

 stock at Nawalia, Luangwa Valley. 



Table II. — Percentage of various species of game found infected 

 with trypanosomes pathogenic to man or domestic 

 stock at Ngoa, Congo Zambesi watershed. 



This investigation, therefore, made it perfectly clear that the 

 main reservoir of the trypanosomes of man and domestic stock 

 is the big game. 



Having ascertained these two essential facts, namely that the 

 tsetse fly, Glossina morsitans, is the vector by which the disease 

 is spread, and that the big game is the inexhaustible reservon- of 

 the virus which causes the disease, we are faced with the problem 



