XXVI 



FLIES AND SLEEPING SICKNESS 



MODERN medical writers recognise the part played by 

 flies in the dissemination of disease ; they multiply 

 upon organic refuse of every kind, and if the temperature 

 be favourable for their development, refuse and dead 

 animal bodies abundant, flies may become a plague. 

 They lay their eggs in carcases at the very instant of 

 death and the species of flies and beetles which infest 

 dead bodies are so numerous that the phrase " Fauna of 

 Corpses " is justified. Linnaeus is credited with the 

 statement that three meat-flies by reason of their rapid 

 multiplication would consume a dead horse quicker than 

 a lion. Moses turned his Egyptian experience to good 

 account, for he recognised the value of the prompt 

 burial of organic refuse, and gave explicit instructions 

 for the burial of excrement (Deut. xxiii. 12, 13). 



Apart from the irritation and annoyance caused by 

 flies (and to this day Egypt is plagued with them), 

 there are very serious diseases afflicting man and 

 animals in which flies play a very active part. The 

 one with which we are specially concerned is known as 

 sleeping-sickness. 



The consideration of the stages by which knowledge 

 has been gained concerning the part played by Tsetse 

 flies in spreading this, at one time, mysterious disease 

 is brimful of interest, and leads us to admire the energy 

 of the skilful investigators who have devoted them- 



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