477 



The Morphology of Trypanosoma simiae, sp. nov. 

 By Colonel Sir David Bruce, C.B., F.R.S., A.M.S. ; Majors David Harvey, 

 and A. E. Hamerton, D.S.O., R.A.M.C. ; Dr. J. B. Davey, Nyasaland 

 Medical Staff; and Lady Bruce, R.RC. (Scientific Commission of the 

 Koyal Society, Nyasaland, 1911-12.) 



(Received August 3, 1912.) 



[Plate 13.] 



Introduction. 



This species of trypanosome, which does not seem to have been described 

 before, is remarkable in that it attacks only such widely different animals as 

 the monkey and the goat. Oxen, baboons, dogs, guinea-pigs, and white rats 

 appear to be immune. The rapidity with which it kills monkeys is very 

 striking. In a series of 19 the average duration of life after the trypano- 

 somes were first seen in the blood was only 2 - 9 days. Its action on animals, 

 its reservoir, its carrier, and cultivation, have not been fully worked out, and 

 will form the subject of a future paper. In regard to its carrier, it may be 

 stated that in this district it is Giossina morsitans, and that scarcely a single 

 cage of flies is brought to Kasu Hill from the neighbouring " fly-country " 

 but is found to be infected with this trypanosome. 



A. Living, Unstained. 



Trypanosoma simim shows active translatory movements, when alive : some 

 individuals pass completely across the field of the microscope. Apparently 

 the usual mode of progression is flagellum first, but occasionally an 

 individual can be seen to move a short distance in the opposite direction. 



B. Fixed and Stained. 



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

 in the ' Proceedings.'* 



Length. — The following table gives the length of this trypanosome as 

 found in the monkey and the goat, 500 trypanosomes in all. 



* ' Eoy. Soc. Proc.,' 1909, B, vol. 81, pp. 16 and 17. 



