493 



Description of a Strain of Trypanosoma brucei from Zululand. 

 Part I. — Morphology. 



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

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

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

 1912-14.) 



(Keceived February 24, — Read March 26, 1914.) 

 [Plates 21-23.] 



Introduction. 



In July, 1912, Dr. A. Theiler, C.M.G., Director of Veterinary Research 

 (Union of South Africa), Pretoria, sent this Commission several blood 

 preparations taken from horses and dogs supposed to be suffering from 

 nagana. Much to the surprise of the Commission, a large percentage of 

 these trypanosomes showed posterior-nuclear forms. This disposed of the 

 contention that the so-called Trypanosoma rhodesiense could be distinguished 

 from other species of trypanosomes by this peculiarity, and first led the 

 Commission to suspect that T. rhodesiense was in reality T. brucei. 



Dr. Theiler was then asked to send the living strain through to the 

 Commission in Nyasaland, and this, after several failures, was at last 

 successful. 



The history of the strain is as follows : Mr. A. W. Shilston, Veterinary 

 Research Division, Pietermaritzburg, writes that it originated in a mule 

 which was naturally infected at Somkele in Zululand. A dog was inoculated 

 from this mule and brought to the Veterinary Research Laboratory at 

 Pietermaritzburg, where sub-inoculations into a series of animals were made. 

 Mr. Shilston says there is no possibility of this strain having been mixed 

 with any other, as, at the time he was working at it, it was the only species 

 of trypanosome maintained at the laboratory. He also states that he — in 

 order to prove that he was dealing with a single species of trypanosome and 

 not with a mixed infection — infected rabbits with single parasites, and the 

 resulting infections showed the same morphological characters as the original 

 strain. 



From Pietermaritzburg the strain was transferred to Pretoria. Mr. William 

 Robertson, acting director during the absence on leave of Dr. Theiler, informs 



* Major Harvey, R.A.M.C., resigned from the Commission and left Kasu, September 

 16, 1913. He was succeeded by Captain Watson, E.A.M.C., who arrived November 2, 

 1913. 



VOL. LXXXVII. — B. 2 Q 



