THE GENUS TRYPANOSOMA 



265 



life was a second English sacrifice to this end, and liis own obser- 

 vations, together with those of Todd, Koch, Brumpt, Greig, Gray, 

 Mincliin, Xabarro, and a host of others, have made Trypanosoma 

 cjumhiense one of the best known of all mammalian trypanosomes. 



In the meantime other students of the protozoa were showing the 

 connections between different species of vertebrate trypanosomes and 

 invertebrate transmitting forms, so that today not only biting flies, but 

 moscjuitoes, lice, and leeches are known to carry trypanosomes from 

 one vertebrate host to another, while only one case of direct trans- 

 mission from animal to animal has been demonstrated. This is of 

 considerable interest, as showing the power of trypanosomes to pene- 

 trate membranes, the organism Trypanosoma equiperdum being trans- 



Fi«. 104 



A tsetse fly (Glossina longipennis, Corti, from Sonialilancl) in resting attitude, showing 



position of wings. ( X3' .) 



mitted bv coitus, and thus yiviny; rise to the disease dourine or mal 

 do coit. Koch and Doflein ('09) suggest that sleeping sickness may 

 be transmitted in the same wav. 



Very great importance attaches to the happenings within the body 

 of the blood-sucking host, and here the matter is still in the whirl of 

 controversy. I^ruce states that in the hundreds of tsetse flies (Aainincd 

 by him he has never found ditl'erent stages of the parasite in the diges- 

 tive tract and no indication whatsoever of migration into the body 

 cavity of the fly. He regards the fly as a mere passive carrier of the 

 protozoon, transmitting the disease during a limited period, by iuocu- 

 liiliug the victim with tryj)anosom('s adhering to (he jjroboscis either 

 inside or out. In this lie is suj)porte(l by Koch, Moore and Hreinl, 

 Xovy, R(uibiiiid, and a host of others, who note that the organisms 



