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Experiments to Investigate the Infectwity of Glossina palpalis 
Fed on Sleeping Sickness Patients under Treatment. 
By Colonel Sir Davin Bruce, C.B., FIRS., A.MS.; Captains A. E. 
Hamerton, D.S.O., and H. R. Bateman, R.A.M.C. (Sleeping Sickness 
Commission of the Royal Society, Uganda, 1908-10); and Dr. R. van 
SOMEREN, Uganda Medical Staff. 
(Received November 23, 1910,—Read February 2, 1911.) 
Introduction. 
It is well known that there are cases of Sleeping Sickness in man which, 
under treatment, may enjoy long periods of apparent good health. In 
these cases the individual is often able to live an active life, and insists on 
being at liberty to go about as he pleases. In Uganda care is taken to 
prevent such cases entering the fly-areas; but the difficulty in maintaining 
a supervision strict enough to check cccasional visits to these areas is 
obviously great, and in other countries may be insuperable, so that the 
question as to how drug treatment can influence the infectivity of these 
patients to the fly may be considered to be of importance. 
Other points arise from the consideration of this question, viz.:—Can 
one or more doses of a trypanocidal drug render a Sleeping Sickness patient 
non-infective to Glossina palpalis? Does prolonged treatment during any 
stage of the disease render cases of Sleeping Sickness innocuous to the fly ? 
If it be proved that the treatment of Sleeping Sickness patients by certain 
drugs does not prevent them infecting Glossina palpalis, then what per- 
centage of cases give a positive result? and what percentage of flies are 
infected from these cases, as compared with the number of flies infected from 
untreated cases ? 
To answer these questions it is necessary to classify under various 
headings the patients who are the subjects of this paper; to state whether 
treated or untreated; if the latter, to give details concerning the nature of — 
the treatment, the duration of treatment, and the total quantity of drugs 
received. The presence or absence of Z’rypanosoma gambiense in the blood 
or lymph glands of each patient should also be noted. 
The classification of patients, according to the stage of the disease in which 
they present themselves, is that adopted by Dr. A. D. P. Hodges, C.M.G., 
Principal Medical Officer, Uganda, in the “ Progress Report on the Uganda 
Sleeping Sickness Camps,” from December, 1906, to November 30, 1908. 
