97 



The Trypanosome causing Disease in Man in Nyasaland : The 

 Liwonde Strain. Part I. — Morphology. Part II. — Suscepti- 

 bility of Animals. 



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

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

 Bruce, B.B.C. (Scientific Commission of the Boyal Society, Nyasaland, 

 1912-14.) 



(Eeceived April 7, — Eead June 25, 1914.) 

 Introduction. 



This strain was obtained in the "fly-area" of the Upper Shire Valley, in 

 the Liwonde district, which is situated about 100 miles south of the 

 " Proclaimed Area."* At the time it was procured no cases of trypanosome 

 disease in man had been reported from this district ; lately, a case has been 

 discovered at Mpimbi, in the south of the district, about 150 miles south of 

 the " Proclaimed " or Sleeping Sickness Area. 



Three dogs infected with the wild Glossina morsitans strains of this 

 trypanosome were brought to Kasu, and other animals — monkeys, dogs and 

 rats — were inoculated from them. 



For purposes of description, measurement and comparison, only trypano- 

 somes from rats were used. 



I. Morphology of the Liwonde Strain. 



A. Living, Unstained. 



All three strains agree in being actively moving flagellates, but with little 

 or no translatory movement. 



B. Fixed and Stained. 



The blood films were fixed, stained and measured as previously described 

 in the ' Proceedings.'t 



Before proceeding to describe the three strains in detail, it may be stated 

 here that in general appearance, shape, position of nucleus, size of micronucleus, 

 contents of cell, and undulating membrane, all three strains were similar, and 

 in no way differed from the various strains of the trypanosome causing 

 disease in man in Nyasaland which have already been described. 



* " Trypanosomas Found in Wild Glossina morsitans and Wild Game in the ' Fly-belt ' 

 of the Upper Shire" Valley," ' Koy. Soc. Proc.,' B, vol. 88, p. 38 (1914). 

 t B, vol. 81, pp. 16 and 17. 



