causing Disease in Man in Nyasaland. 



Ill 



Conclusions. 



1. The three wild G. morsitans strains from the Liwortde district resemble 

 each other closely, and all belong to the same species of trypanosome. 



2. The Liwonde strain belongs to the same species as that occurring in 

 man, wild game, and wild G. morsitans inhabiting the " Proclaimed Area," 

 Nyasaland — T. brncei vel rhodesiense. 



3. Hence it would appear that wild G. morsitans occurring in a district 

 100 miles south of the " Proclaimed Area " are infected with the trypanosome 

 which causes the human trypanosome disease of Nyasaland. 



The Trypanosome causing Disease in Man in Nyasaland. The 

 Naturally Infected Dog Strain. Part I. — Morphology. 



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

 Hamerton, D.S.O., and Captain D. P. Watson, E.A.M.C. ; and Lady 

 Bruce, R.R.C. (Scientific Commission of the Eoyal Society, Nyasaland, 

 1912-14.) 



(Received April 7,— Read June 25, 1914.) 

 '[Plates 9-11.] 



Introduction. 



This strain differs so much from the others that it is doubtful if it should 

 be included among the various strains already described, Human,* Wild- 

 game ; f Wild Glossina morsitans,^ Mzimba,§ etc. It has only been found on 

 three occasions and, curiously enough, each time in a native dog. 



The three dogs suffering from trypanosome disease were brought up to 

 Kasu from the " Proclaimed Area," where they had probably been naturally 

 infected by the wild G. morsitans, hence the name " The Naturally Infected 

 Dog Strain." 



All the infected dogs coming from this area did not show this strain ; for 

 example, Dog 553 was infected with a trypanosome resembling the ordinary 

 Human strain. 



• 



* 1 Eoy. Soc. Proc.,' B, vol. 85, p. 423 (1912), and vol. 86, p. 285 (1913). 

 t Ibid., B, vol. 86, p. 394 (1913). 

 | Ibid., B, vol. 86, p. 408 (1913). 

 § Ibid., B, vol. 87, p. 26 (1913). 



