THE WILD FAUNA OF THE EMPIRE 41 



country, the common species of tsetse-fly being Glossina morsitans, 

 known to transmit the trypanosome of nagana to domestic animals. 

 The presence of this fly transmitting a fatal disease to cattle and 

 all transport animals prohibits the settler from taking up much 

 fertile good grazing land in Northern Ehodesia and adds great 

 difficulties to the growing mining industries. 



Much is still to be learned about the tsetse-fly. My ow^n ex- 

 perience of eight years in tsetse-fly countries has convinced me 

 that where there is no game there can be no Glossina morsitans ; 

 that the destruction of game effects the disappearance of this tsetse ; 

 and that where tsetse originally existed, the reappearance of game 

 means the reappearance of the tsetse-fly. 



This is instanced by the destruction of game by the rinderpest 

 in Northern Rhodesia, and the subsequent diminution of and dis- 

 appearance in large areas of the tsetse-fly. Later the game has 

 increased, and with it the tsetse-fly and the disease have come back. 



Trypanosomiasis in man (sleeping sickness) is spread by a tsetse- 

 fly. Glossina palpalis is known to spread this terrible disease. 

 But, again, much is to be learned, and the highest authorities in 

 that branch of medical science which has studied this disease and 

 its transmission wdll not admit that Glossina morsitans is not a 

 transmitter of sleeping sickness, claiming even that it probably 

 can transmit, and that until the contrary is proved it must be 

 regarded as dangerous. 



The schools of tropical medicine are actively studying both in 

 Europe and Africa trypanosomiasis and the means by which that 

 disease is spread. 



It may be — it seems even probable that it is the case — that the 

 presence of the larger mammals on which the tsetse-fly lives means 

 incidentally the presence of and spread of disease fatal to man and 

 domestic animals. If this is so, and it is to be hoped that medical 

 science will soon be able to give definite information on this sub- 

 ject, there should be no attempt to preserve game in tsetse-fly areas. 

 Happily there is plenty of Africa free from tsetse-fly in which 

 game abounds and in which preservation is possible. I believe 

 that effective prohibition of the sale of powder to natives is the first 

 and most important step necessary to preserve all species now 

 existing in Northern Rhodesia, and that if the Government, having 

 ensured that extermination by natives is impossible, imposes from 

 time to time, as may seen necessary, judicious restriction of the 

 number of head of game of each variety killed by hunting parties, 

 there will be no danger of the extermination of any species. 



