187 



On the Non-identity of Trypanosoma brucei, Plimmer and 

 Bradford, 1899, with the Trypanosoma of the Same Name 

 from the Uganda Ox. 



By J. W. W. Stephens, M.D., D.P.H. (Cantab.), and B. Blacklock, 



M.D., D.P.H. 



(Communicated by Sir R. Ross, K.C.B., F.E.S. Received December 7, 1912, — 



Read January 23, 1913.) 



Introduction. 



Before considering our own observations it will be necessary to review 

 briefly previous statements regarding the morphology of Trypanosoma brucei. 



(1) Bruce (1) states that the hsernatozoa vary among themselves a good 

 deal in shape and size and seem to take on slightly different forms in 

 different species of animals. He publishes four figures depicting nine 

 trypanosomes. Possibly one or two of the five figured from the dog might 

 be considered to be " stumpy " forms. 



(2) Kanthack, Durham, and Blandford (2) state that the Nagana parasites 

 vary considerably both in size and form. They may be long and pointed 

 and sometimes stouter, some individuals are short and thick with a short 

 flagellum, their protoplasm being crowded with granules. This description 

 suggests dimorphism, but it should be noted that forms without a free 

 flagellum are not mentioned. No slides were available belonging to these 

 observers, but Dr. Durham kindly lent us a large series of photographs. On 

 examining these, one or, perhaps, two show a " stumpy " form, but it is 

 difficult to be certain, and the uniformity of the remainder is striking. 

 They state that " the material for our observation was obtained in the first 

 instance from the blood of a dog infected by the disease on the voyage from 

 Africa, and brought to England in November, 1896, by Dr. Waghorn." 



This animal we believe to be the origin of the strain of T. brucei, Plimmer 

 and Bradford, 1899, described by these authors, and at present maintained in 

 England, so far as we can gather, solely at Liverpool. 



It is not stated above from what animal the dog was infected on the 

 voyage, nor is it stated what the exact original source of the strain derived 

 from Zululand was. 



(3) Plimmer and Bradford (3 and 4) describe four forms in the blood, but 

 neither their description nor figures suggest that they have seen stumpy 

 forms. They describe " a large hyaline form." " This organism is much 

 larger than the ordinary adult form, and is much wider, often more than 



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