1912.] Bradford, 1899, and Trypanosome from Uganda Ox. 189 



1912 for a short period but was returned to us again by Prof. Mesnil, who 

 had previously received it from us. 



We made then a preliminary examination of these two strains, and found, 

 to our surprise that they could easily be distinguished morphologically. 



We next proceeded to make a detailed examination of the two strains in a 

 series of slides throughout the entire period of infection in various animals, 

 viz., rats, guinea-pigs, and rabbits. As the result, we believe we have 

 established the following facts : — 



(a) The Zululand strain is typically monomorphic. The trypanosomes are 

 long, with a long free flagellum. We must admit, however, that it is 

 possible (as we believe is the case also in another typically monomorphic 

 trypanosome, viz., T. evansi) to find by long search short forms which 

 somewhat resemble true stumpy forms, but we must emphasise the fact that, 

 in all the slides we have examined, prolonged search is necessary to find them. 



(b) We have also verified the fact that Laveran's T. brucei strain also is, 

 as he says, monomorphic. The origin of this strain seems uncertain. 

 Laveran probably received it from Ehrlich, but where the latter got it from 

 cannot now be ascertained. Unless it came from England, there must be 

 two monomorphic T. brucei strains in existence, not to mention the possibility 

 of other T. brucei strains of uncertain parentage in various laboratories. 



We have examined also old slides from the Zululand strain lent us by 

 Prof. Nuttall, Colonel Skinner, E.A.M.C., and Dr. Plimmer.* All these were 

 monomorphic. We repeat here that in these films, or at least some of them, 

 it was possible by long search to find a short form somewhat resembling a 

 stumpy form, but not having the somewhat indefinable characteristic appear- 

 ance of the latter. 



(c) The Uganda strain, on the contrary, is typically dimorphic, i.e., besides 

 the usual long forms of trypanosomes, stumpy forms are readily found, even 

 in abundance occasionally, when the infection is well marked. Bruce (6), as 

 we have noted above, states that this trypanosome has 26 per cent, of non- 

 flagellated forms. 



The typical stumpy form we may define as a short, thick trypanosome, 

 12-14 /j,, almost straight or slightly curved along one edge, while along the 

 other the membrane is thrown into bold folds, there berns no free flaszellum 

 or at times a very short or doubtfully free one. 



It is thus easy to distinguish a typical Uganda specimen from a Zululand 

 specimen, and, in fact, we may express the difference in this way, that it is 



* We desire here to express our thanks to these gentlemen for their kindness in 

 sending us slides. 



P 2 



