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Morphology oj Various Strains of the Trypanosome causing 

 Disease in Man in Nyasaland. I.- — The Human Strain. 



By Surgeon-General Sir David Bruce, C.B., F.R.S., A.M.S. ; Majors David 

 Harvey and A. E. Hamerton, D.S.O., E.A.M.C. ; and Lady Bruce, 

 R.R.C. 



(Received February 8,— Read March 6, 1913.) 

 (Scientific Commission of the Royal Society, Nyasaland, 1912.) 

 Introduction. 



In order to gain a general idea of this important species of trypanosome, it 

 will be necessary to study as many individual strains as possible. It may be 

 thought unnecessary to describe each strain so much in detail, but without 

 this it will be impossible to get any order out of the chaos which rules at 

 present in the classification of the African species of trypanosomes pathogenic 

 to man and the domestic animals. 



Up to the present the Commission have only had an opportunity of work- 

 ing with five human strains. Four of these are from natives infected in the 

 Sleeping- Sickness Area, Nyasaland, the fifth from an European who contracted 

 the disease in Portuguese East Africa. It is intended, in later papers, to 

 describe five strains from wild game and the same number from the tsetse 

 fly, Glossina morsitam. 



The human strains are named : I, Mkanyanga ; II, E ; III, Chituluka; 



IV, Chipochola ; and V, Chibibi. 



I. Morphology of Strain I, Mkanyanga. 

 Tins has already been dealt with in a previous paper.* 



II. Morphology of Strain II, E . 



The following table gives the average length of this trypanosome as found 

 in goats, sheep, monkeys, dogs and rats, 1500 trypanosomes in all, and also 

 the length of the longest and shortest : — 



* 'Roy. Soc. Proc.,' 1912, B, vol. 85, p. 423. 



