264 



THE PATHOGENIC FLAGELLATES 



lived in their blood as harmless guests, just as the trypanosome of the 

 rat lives in the blood of that animal."^ 



In a very similar way the cause of human trypanosomiasis, Try- 

 panosoma gambiense, was shown to be transmitted by another tsetse fly, 

 Glossina palpaUs (Fig. 103). Button, whose own life was the first to 

 be martyred in the cause of sleeping sickness, gave the name to this 

 trypanosome, which was first seen by Forde, in 1891, in the blood of 

 victims of gambia fever. Castellani ('03), later, found trypanosomes 

 in five cases of sleeping sickness in the cerebrospinal fluid, and in one 

 of these cases, also, in the blood. This organism was regarded by 



Fig. 103 



Glossina palpalis, Rob. X 3%. 



Castellani as different from all others and named by him Tryp, 

 ugandeiise. Bruce, in the same year, confirmed these observations of 

 Castellani, and also those of Button and Todd on gambia fever, and 

 succeeded in demonstrating that the latter is only the first phase of 

 sleeping sickness, and that the trypanosome is conveyed to man by 

 only one agent, a species of tsetse fly. 



Confirmatory observations followed rapidly, English, German, 

 French investigators risking their lives in scientific rivalry to get at the 

 life history of this protozoan pest and its insect carrier. Tulloch's 



' Bruce, Tryiianosomiasis, Osier's Modern Medicine, pp. 462 to 464. 



