342 TRYPANOSOMA DIMORPHON [CH. 



a maximum of 19 microns. The free part of the flagellum 

 is from i to 5 microns in length. In all other characters 

 T. uniforme is the same as cazalboui, with the exception that 

 there is no marked narrowing opposite the trophonucleus as in 

 the case of the latter species. 



Mode of infection. Fraser and Duke have shewn that the 

 Glossina palpalis in the .neighbourhood of Lake Victoria are 

 naturally infected with this trypanosome, for after 1020 flies 

 from the lake-shore had been fed on a goat it became infected 

 with T. uniforme. Also it was shewn experimentally that 

 laboratory-bred palpalis were capable of transmitting this 

 species of trypanosome from infected to healthy animals. Of 

 six experiments four were successful. The flies became infective 

 in from 27 to 37 days, and the infection in the fly was always 

 limited to the proboscis as in the case of cazalboui. 



REFERENCES. 

 Bruce, Hamerton, Bateman and Mackie (1911). Proc. Roy. Soc. B, 563, 



p. 176. 

 Fraser and Duke (1912). Ibid. B, vol. lxxxv. p. i. 



Trypanosoma dimorphon Laveran and Mesnil, 1904. 



Synonyms. T. confusum Montgomery and Kinghorn, 1909. 

 T. froheninsi Weissenborn, 191 1. 



General account. In 1902, Button and Todd in the course 

 of their expedition to the Gambia observed trypanosomes in 

 the blood of some of the horses in that region. 



Under the title of " Horse trypanosome " they described 

 and figured the parasites occurring in one of these horses. The 

 .emarkable feature about the infection was the occurrence of 

 small tadpole-shaped trypanosomes without any free flagellum, 

 side by side with long and slender forms with a long free flagel- 

 lum. Button and Todd did not name their horse trypano- 

 some, a fortunate omission, since there is practically no doubt 

 that several distinct species were in their hands. One of these 

 infected horses was sent over to Liverpool and from here the 

 strain was sent across to Laveran and Mesnil in Paris, where 

 they studied the morphology of the trypanosome, and, in 1904, 

 published a description of it under the name of T. dimorphon. 



