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The Development of Trypanosomes in Tsetse Flies. 



By Colonel Sir David Bruce, C.B., F.RS., Army Medical Service; 

 Captains A. E. Hamerton, D.S.O., and H. E. Bateman, Eoyal Army 

 Medical Corps ; and Captain F. P. Mackie, Indian Medical Service. 

 (Sleeping Sickness Commission of the Eoyal Society, 1908-10.) 



(Eeceived April 18,— Eead May 5, 1910.) 



In the ' Proceedings ' of the Eoyal Society (B, vol. 81, 1909) a paper was 

 published describing a single experiment illustrating the development of 

 Triipanosoma gambiense in Glossina ^'X'^^pnlis. This experiment was carried 

 out at Mpumu, Uganda, near Lake Victoria, in the spring of 1909. Since 

 that date many experiments, on the same lines, have been made, not only 

 with Trypanosoma rjamhicnse but also with Trypanosoma diviorphon, Trypano- 

 soma namim, and Trypanosoma vivax* It is proposed to describe these further 

 experiments in this paper. 



It will be remembered that Kleine, in German East Africa, at the end of 

 1908, made the discovery that Glossina paljmlis could convey Trypanosoma 

 hrucei for some 50 days after the fly had fed on an infected animal. 

 Following Kleine's lead, our experiments were carried out, at first with 

 Lake-shore flies, afterwards with flies bred in the laboratory. 



A. Tlte Development of Trypanosoma gambiense in Glossina palpalis caught 



on the Lake-shore. 



These experiments were carried out with ordinary wild tsetse flies caught 

 on the Lake-shore, and tlierefore open to the doubt that some of them may 

 have beeu naturally infected when they were captured. As there is some 

 evidence that one fly in 400 or 500 of the wild Lake-shore flies is found to 

 be naturally infected, it is evident tliat these previously infected flies may 

 lead into error. It will be seen later that this risk is not run when flies 

 bred in the laboratory are used. 



The flies when brought up from the Lake-shore were kept in small l)0xes, 

 with mosquito-netting sides, and placed over dishes containing water, to 

 imitate, as far as possible, their natural conditions. It may be remarked 

 here tliat these tsetse flies are so numerous on the shores of Victoria Nyanza, 

 and the 8Upi)ly so unending, that the fly-boys brought up some 500 every 

 day, and these usually cauglit at only one or two spots. 



* Tlieae naineH may require to be changed, when the trypanosomes affecting domestic 

 aninialH in T^ki'"'"' come to lie described. 



