415 
TSETSE FLIES AND TRYPANOSOMIASIS. 
SOME QUESTION? SUGGESTED BY THE LATER HISTORY OF THE 
SLEEPING SICKNESS EPIDEMIC IN UGANDA PROTECTORATE. 
By H. LYNDHURST DUKE, M.D., D.T.M. & H. (Camb.), 
Bacteriologist, Uganda Protectorate. 
CONTENTS. 
PAGE 
Part I. I. Historical . ..415 
II. Assumptions on which Sir H. Hesketh Bell based his 
suppressive measures . . . . . . 417 
III. Outcome of the measures . . . . . . 418 
IV. Examination of the available statistics bearing on the 
epidemic ........ 418 
V. The justification for the preventive measures . . 421 
VI. Early criticisms of the measures . . . 421 
VII. Comparison between bovine and human trypanosomi¬ 
asis in Uganda .422 
Part II. VIII. The tsetse fly as a transmitter of human trypanosomes 423 
IX. Comparison between G. palpalis and G. morsitans as 
vectors of mammalian trypanosomes . . 424 
X. Part played by each of the above two methods of trans¬ 
mission in the perpetuation of trypanosome 
strains ........ 425 
Part III. XI. Conclusions to be reached regarding the trypanosomes 
present in man at the time of the epidemic from a 
consideration of the mortality statistics . 427 
XII, General conclusions.428 
PART I. 
I. HISTORICAL. 
The actual commencement of the great wave of human trypanosomiasis, 
which claimed so many thousands of lives along the shores of Lake Victoria, 
is difficult to determine. The attention of Europeans was first attracted to the 
disease early in 1901, when eight cases of sleeping sickness were admitted to 
Mengo hospital by the Drs Cook, who had been established in Uganda some 
five years, to whom the clinical picture was quite new. Enquiry among the 
chiefs of Buganda revealed the fact that sleeping sickness was known to the 
natives as mongota, and was more prevalent in the eastern portion of the Pro- 
Parasitology xi 27 
