(148) 



STRUCTURE, DEVELOPMENT, AND BIONOMICS OF HOUSE-FLY. 389 



tremely sensitive to tlie change of temperature, and that the 

 cold nights kill them off rapidly." In the discussion on this 

 paper Church stated that " many nurses told me that if one 

 went into a tent or ward in which the patients were suffering 

 from a variety of diseases, one could tell at onoe which were 

 the typhoid patients by the way in which the flies clustered 

 about their mouths and eyes while in bed." It was further 

 stated in the discussion that where the Americans used quick- 

 lime in their latrines the cooks in the neighbouring kitchens 

 found that the food became covered with quicklime from the 

 flies which came from the latrines to the kitchens. 



Dr. Tooth, in a letter to me, says : " I am afraid my written 

 remarks hardly express strongly enough the importance that 

 I attach to flies as a medium of spreading infection. Of course 

 I do not wish to under-rate the water side of the question, 

 but once get, by that means, enteric into a camp the flies, in 

 my opinion, are quite capable of converting a sporadic incidence 

 into an epidemic. A pure water supply is an obvious necessity, 

 but the prompt destruction of refuse of every description is 

 every bit as important." 



Smith (1903), in speaking of his experiences in South 

 Africa, says that : " On visiting a deserted camp during the 

 recent campaign it was common to find half a dozen or so 

 open latrines containing a foetid mass of excreta and maggots." 

 Similar observations were made by Austen (1904), who, de- 

 scribing a latrine that had been left a short time undisturbed, 

 says : "A buzzing swarm of flies would suddenly arise from it 

 with a noise faintly suggestive of the bursting of a percussion 

 shrapnel shell. The latrine was certainly not more than one 

 hundred yards from the nearest tents, if so much, and at meal- 

 times men's mess-tins, etc., were always invaded by flies. A 

 tin of jam incautiously left open for a few minutes became a 

 seething mass of flies (chiefly Pycnosoma chloropyga 

 Wied), completely covering the contents." 



Howard (1900) referring to an American camp, where no 

 effort was made to cover the faeces in the latrines, says : " The 

 camp contained about 1200 men, and flies were extremely 



