CHAPTER I 



INTRODUCTION 



There would seem to have been a somewhat strong prejudice 

 against flies as remotely as the time of the fourth plague of 

 Moses, when " there came a grievous swarm of flies into the 

 house of Pharaoh, and into his servants' houses, and into all the 

 land of Egypt ; the land was corrupted by reason of the swarm 

 of flies." 



From time to time since that date various writers, usually 

 without bringing forward any definite proofs, have connected 

 swarms of flies with epidemics of various kinds, or with unhealthy 

 seasons. Sydenham (1666), for example, remarked that if swarms 

 of insects, especially house-flies, were abundant in summer, the 

 succeeding autumn was unhealthy. Until recently, however, 

 little trouble was taken to procure definite evidence in regard to 

 their relationship to disease, practically nothing was known of 

 their life-histories or habits, and many curious statements about 

 them were unhesitatingly accepted. In 1824, for example, an 

 interesting case of myiasis was reported in a lady, who after a 

 prolonged course of earth eating, " became subject to constant 

 vomiting, and produced a remarkable biological collection, in 

 which, among many strange beasts, dipterous larvae ' literally 

 teemed,' larvae, pupae and imagines being ejected together. 

 One realises the paucity of knowledge in the last century when 

 one reads that it inspired ' a feeling of horror to see them (the 

 larvae) frisking along, occasionally expanding their jaws, and 

 extending their talons,' and although the doctor himself witnessed 

 the extrusion of these forms, it is impossible not to be a little 



G.-S. I 



