Further reports (no. 6) on flies as carriers of infection.

Date:
1913
Catalogue details

Licence: In copyright

Credit: Further reports (no. 6) on flies as carriers of infection. Source: Wellcome Collection.

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    originated from larvae which were prevented from attaining their full dimensions owing to failure of their food-supply. These remarks bear on the fact that specimens of Homalomyia cani- cularis are sometimes supposed to be “ young house-flies.” Mr. Austen’s notes on flies sent to him for examination in 1908, showed that in every case Musca domestica, Linn., largely outnumbered the other species. After this the commonest species were Homalomyia canicularis, Linn., Calliphora erythrocephala, Mg. (the blue-bottle), and Muscina stabulans, Fin. He notes the occurrence of Proto calliphora grcenlandica, Ztt., in Bermondsey, as worthy of special mention. Larvae of this fly, which feed as a rule on carrion, are evidently imported in sacks of old bones received at a local glue and size works, and it is possible that the species also breeds in these works. P. groen- landica is not a species which is ordinarily found in dwellings, even in the country. Its occurrence in some numbers on August 10th, in the kitchen of a London County Council School about 150 yards from the glue and size works in question, is therefore, specially noteworthy. Mr. Jepson’s observations on the breeding of the common house-fly (Musca domestica) during the winter months show that flies do not disappear altogether during the winter, but may be found in places where the temperature conditions, &c., are favourable. Whether under such circumstances they ordinarily continue to breed as in the warmer months cannot be said, but under experimental conditions they will breed in winter. On the other hand, the fact that flies captured during the winter appear more hardy and long-lived than those taken and kept under the same conditions in the summer, seems to support the view that the former may persist throughout the winter as adults. II. The contents of the second report (No. 16) are as follows : — (1) Memorandum on Lines of Investigation : by Dr. Cope- man. (2) Notes on Colouring Flies for Purposes of Identification: by Mr. Jepson. (8) Preliminary note on Examination of Flies for the Presence of Bacillus coli: by Dr. Graham-Smith. (4) Abstracts of Literature and Bibliography: by Prof. Nuttall and Mr. Jepson. In his preliminary memorandum Dr. Copeman set out certain conditions as necessary for securing comparable data. Mr. Jepson, working at the colouring of flies for purposes of identification, showed that the employment of finely-powdered coloured chalks gave the most satisfactory results, and that of the colours employed Yelloiv and Brick Bed were the best, lasting in the first case for nine days and in the second case 20 days. The dusting was accomplished by placing the balloon containing the flies in a paper bag, pouring in the ground-up chalk, and gently shaking it about. By this means the flies became completely covered with chalk, which persistently adhered to the upper portion of the thorax and the base of the wings. Dr. Graham-Smith’s preliminary note on the presence of the colon bacillus dealt with the examination of 148 flies, mainly