The house fly : Musca domestica, Linnæus a study of its structure, development, bionomics and economy / by C. Gordon Hewitt.

  • Hewitt, C. Gordon (Charles Gordon), 1885-1920.
Date:
1910
Catalogue details

Licence: In copyright

Credit: The house fly : Musca domestica, Linnæus a study of its structure, development, bionomics and economy / by C. Gordon Hewitt. Source: Wellcome Collection.

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    examination from infected and uninfected houses in Paddington and from a country house situated many miles from London, -where no cases of diarrhoea had occurred, at any rate -within a radius of two miles. The flies were killed -with ether vapour and crushed with a sterile rod in peptone broth. The result was that Morgan’s bacillus was isolated from nine of the thirty-six batches from infected houses and from one of the thirty-two batches from uninfected houses. It was also got in five out of twenty-four batches from the country house.” Dr. Morgan in the course of a letter to me says: “ I certainly think they are carriers of summer diarrhoea, and the variety I especially suspect of doing this is the Musca domestica.” Hamer in his first report (1908) points out a difficulty in the way of accepting this relation of flies to summer diar- rhoea. He states: “ It should be pointed out that there are certain difficulties in the way of accepting the thesis that the correspondence exhibited in the curves [he refers to the fly curve and diarrhoea curve] affords reason for concluding that flies and summer diarrhoea stand to one another in relation of cause and effect. At the commencement of the hot summer weeks, when the number of flies has begun to show marked increase, the diarrhoea curve is rapidly rising. After some weeks the number of flies reaches the maximum, and then diminishes, and so, in almost precise correspon- dence, does the amount of diarrhoea. A period is later reached, towards the close of the hot weeks, at which the number of flies is still as markedly excessive as at the earlier period when the amount of diarrhoea was increasing, but at the later period the amount of diarrhoea is declining; it even anticipates decline in the number of flies. If the fly is to be regarded as the carrier of the organism which causes diarrhoea, it might perhaps have been anticipated that at the later period—the number of flies still being excessive and infective material being then 2>resumably more widely