TSETSE FLIES 848 



appeared in their midst, coming, as it were, from 

 nowhere, and also in spite of the complete absence 

 of Glossina palpalis. They also grew increasingly 

 uneasy at what they regarded as the inexplicable 

 spread in their midst of the common cattle- 

 killing fly Glossina morsitans. To increase the 

 mystery some fine healthy specimens of the 

 newly discovered Rhodesian parasite just re- 

 ferred to were found in the blood of a missionary 

 said to have been undoubtedly infected in 

 Nyasaland, the assumption rapidly gaining 

 ground that the sleeping sickness which had 

 appeared in North-Eastern Rhodesia and the 

 type discovered in Nyasaland were one and the 

 same, and produced by identical means, whatever 

 they might be. As the best method of inquiring 

 into these momentous matters was evidently 

 to employ experts, an important commission 

 was appointed in 1912 by the British South 

 Africa Company to investigate the whole 

 question of sleeping sickness within their terri- 

 tory, and, about the same time, another com- 

 mission, under the able direction of Sir David 

 Bruce, commenced its important labours in the 

 Nyasaland Protectorate. 



The former established itself in the Loangwa 

 Valley, at or near the spot where the case of 

 sleeping sickness which had furnished the clue 

 to the new parasite had been contracted. Here 

 the medical men entrusted with this difficult 

 task began their investigations, and proceeded 

 step by step to trace the source or main reservoir 

 of the parasite, and the reason for the outbreak 



