408 



Morphology of Various Strains of the Trypanosome causing Disease 

 in Man in Nyasaland. — The Wild Glossina morsitans 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., B.A.M.C. ; and Lady Bruce, B.B.C 



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

 (Eeceived February 24— Read April 10, 1913.) 



Introduction. 



These strains were obtained by bringing tsetse flies {Glossina morsitans) to 

 the laboratory from the neighbouring " fly-country " and at once allowing them 

 to feed on healthy animals. The term " wild " is used to distinguish these 

 caught flies from flies bred in the laboratory. The first strain was obtained 

 by feeding the flies on a monkey, the remaining four by feeding on dogs. As 

 soon as the healthy animal was found to be infected other animals were 

 inoculated from it. But, as in the case of the Wild-game strains, only 

 trypanosomes from a single rat were used for purposes of measurement and 

 comparison. 



I. Morphology of Strain I, Wild Glossina morsitans. 



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

 in the rat, 500 trypanosomes in all, and also the length of the longest and 

 shortest. 



Table I. — Measurements of the Length of the Trypanosome of Strain I, Wild 



Glossina morsitans. 



Date. 



Method of fixing. 



Method of 

 staining. 



In microns. 



Average 

 length. 



Maximum 

 length. 



Minimum 

 length. 



1912 



Osmic acid 



Giemsa 



22 -7 



34 -0 



16 -0 



