MASTIGOPHORA 



403 



Other species of animals are not readily infected. Immunity 

 follows recovery. Artificial immunity has been produced by 

 Novy, Perkins and Chambers^ by the injection of a pure culture 

 which had been propagated for six years on artificial media and 

 had lost its virulence. 



There are many other relatively harmless trypanosomes 

 parasitic in -the blood of various mammals. 



Trypanosoma Brucei.- — Bruce in 1895 discovered this organism 



Fig. 161, — The most important trypanosomes parasitic in vertebrates. A, 

 Tr. Uwisi; B, Tr. evansi (India); C, Tr. evansi (Mauritius); D, Tr. brucei; E, Tr. 

 equiperdum; F, Tr. equinum; G, Tr. dimorphon; H, Tr. gambiense. All magnified 

 X 1500. {From Doflein after Novy.) 



in the blood of horses suffering from Nagana, the Tsetse-iiy dis- 

 ease of Zululand. Pure cultures have been obtained in the con- 

 densation fluid of inclined blood-agar by Novy and MacNeal 

 and the injection of pure cultures into animals produces the dis- 

 ease and death. 



Tr. brucei is 1.5 to 5^ wide and 25 to 3 5m long, including the 

 } Journ. Inf. Dis., 191 2, Vol. XI, pp. 411-426. 



