PREFACE. 



The Trustees of the British Museum have authorised the 

 preparation and publication of the present work in view of 

 the great practical importance of an accurate knowledge of the 

 genus of flies to which Wiedemann gave the name Glossina. The 

 discovery by Colonel Bruce of the fact that the common Tsetse-fly 

 of South Africa produces the death of horses and cattle rightly 

 ascribed to its attacks by introducing into the blood of its 

 victims a minute parasite, the Trypanosoma Brucei, has been 

 followed by the discovery of similar parasites in the Indian 

 disease known as Surra, in the Mai de Caderas of South America, 

 in the Dourine of Algeria, and, lastly, in the blood of human 

 subjects. The last and most important discovery is that by 

 Castellani of the occurrence of a Trypanosoma in the cerebro- 

 spinal fluid of nearly seventy per cent, of the cases of sleeping 

 sickness examined for this purpose by him at Entebbe, Uganda, 

 in the early part of this year. It is estimated that thirty 

 thousand of the native inhabitants of the Uganda Province have 

 died of the sleeping sickness since its sudden appearance among 

 them two years ago. 



We are not yet sufficiently acquainted with the facts as to 

 the distinguishing characteristics of the different species of 

 Trypanosoma concerned in causing these diseases. Nor do we 

 know in any case, excepting that of the Nagana disease, what 

 is the nature of the insect (if insect it be, as is probable) by 

 which the Trypanosoma is introduced into the blood of a pre- 

 viously healthy animal or man. In the case of the Nagana 

 disease, we know that a Tsetse-fly ■— Glossijia morsitans of 

 Westwood — is the habitual and specific carrier of th6 parasite. 

 Even though other blood-sucking insects may occasionally act as 

 intermediaries and pass on the Nagana parasite from one animal 

 to another, it is to Glossina morsitans, and possibly also to 



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