36i 



3. T. evansi. — The trypanosome of Surra. A 

 common disease in many parts of India, e.g., 

 Bombay, at certain seasons especially, though 

 probably always in a latent condition. It is 

 possible that its increase at a particular time is 

 associated with the prevalence of a biting fly. 

 Surra is characterized by a similar train of symp- 

 toms to those of Ngana. Rogers states that the 

 disease in India is conveyed by Tabanidae (horse 

 flies). This statement has not yet been confirmed. 



Whether the ' surra ' of camels in India is 

 produced by the same trypanosome there is no 

 evidence to shew. 



Laveran and Mesnil, who have recently 

 been able to make a comparison of T. brucet and 

 T. evansi, state that T. brucet is shorter and more 

 compact than T. evansi. The movements of 

 T. brucei are also less extensive. The posterior 

 end of T. brucei is also blunter than that of 

 T. evansi. The free portion of the flagellum is 

 shorter in T. brucei than T. evansi, and the pro- 

 toplasm of T. brucei has more numerous and 

 larger granules than that of T. evansi. The 

 nuclei and the blepharoplasts are morphologically 

 indistinguishable. Further, the mean length of 

 T. brucei is less than that of T. evansi, and the 

 width of T. brucei is greater. The distinction 

 between Surra and Ngana is, however, best proved 

 by the fact that an animal immunized against 

 Ngana is yet susceptible to inoculation with 

 Surra.' 



4. T. equinum (Mai de Caderas). — In Central 

 and South America. A disease aifecting horses. 



The symptoms — remittent fever, oedema, 

 wasting — resemble those of Ngana and Surra. 



