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The Morphology of Trypanosoma gambiense (Dutton). 

 By Colonel Sir David Bruce, C.B., F.E.S., A.M.S. 



(Received September 29, — Read November 2, 1911.) 

 [Plate 13.] 



Introduction. 



This species, like Trypanosoma brucei, is markedly dimorphic. In size and 

 general appearance also these two species so closely resemble one another 

 that one might easily believe them to be varieties of the same species. There 

 are, however, some slight differences in morphology, which will be described 

 below ; but whether these differences will bear the test of more extended 

 observations remains to be seen. It may be noted that the trypanosomes 

 described come from Uganda, and are not mixed up with strains from the 

 Congo or Rhodesia. 



A. Living, Unstained. 



Trypanosoma gambiense also resembles Trypanosoma brucei in having little 

 or no translatory power when viewed alive in the field of the microscope. 



B. Fixed and Stained. 



The blood films were, as a rule, fixed, stained and measured as previously 

 described in the ' Proceedings.'* 



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

 in man, chimpanzees, monkeys, oxen, antelope and rats, 1,000 trypanosomes 

 in all. (See Table I.) 



From the following table it would appear that Trypanosoma, gambiense is 

 somewhat smaller than Trypanosoma brucei, which was found to average 

 23 - 2 microns in 1,000 individuals, with a maximum length of 38 and a 

 minimum of 13. (See Table II.) 



Great differences are sometimes found in the average length of the trypano- 

 somes in the same individual. For example, in Experiment 114, man 

 (J. M.), on one day, at the beginning of his illness, the average of 

 20 trypanosomes was only 17*0 microns ; whereas, on another day, at a later 

 date, this rose to 25 - 8 microns. 



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

 VOL. LXXXIV. — B. 



