Further reports (no. 4) on flies as carriers of infection.

Date:
1911
Catalogue details

Licence: In copyright

Credit: Further reports (no. 4) on flies as carriers of infection. Source: Wellcome Collection.

    33/52 (page 31)
    4.—Further Observations on the Ways in which Arti- ficially Infected Flies (Musca domestica and Calliphora erythrocephala) carry and distribute pathogenic and other Bacteria. By G. S. Graham-Smith, M.D., University Lecturer in Hygiene, Cambridge. Contents. Page Introduction 31 Experiments designed to ascertain whether flies can infect fluids on which they feed ... ... ... ... ... ... ... 31 Experiments with house flies (M. domestica) 31 Experiments with blow-flies (C. erythrocephala) 35 Observations on the habits of blow-flies and their bearing on feeding experiments 41 Experiments on blow-flies (C. erythrocephala) bred from artificially infected larvae 43 Summary 47 The experiments described in this paper, which were carried on during the year 1910, were designed with the purpose of further investigating certain problems in relation to the distribution of bacteria by flies, to which but little attention was paid in the work described in the last report.# In that report (p. 25) are described certain experiments made with the object of ascertaining whether artificially infected flies can contaminate fluids on which they feed. The experiments were few in number and inconclusive, but seemed to show that flies (iff. domestica) do not usually contaminate fluids on which they feed. This subject has been re-investigated, and, as will be seen in the following pages, it has been shown that both house-flies (M. domestica) and blow-flies (C. erythrocephala) can infect fluid substances for several days after they have been allowed to feed on emulsions of cultures.! Two other problems have also received attention ; the development of infected blow-flies from artificially infected larvae, and the anatomy and function of the oral discs of the proboscis of the blow-fly. The investigations on the latter subject will be described in a separate paper. Experiments designed to ascertain whether Flies can Infect Fluids on which they Feed. Experiments were carried out both with house-flies (M. domestica) which had been caught in traps, and with blow-flies ( C. erythrocephala) which had been bred in captivity from eggs. The fluids used for the experiments were syrup and sterilised milk. I.—Experiments ivith House-flies (M. domestica). Experiment 1.—Flies (M. domestica), confined in three different cages, were allowed to feed for 30 minutes on syrup infected with # Reports to the Local Government Board on Public Health and Medical Subjects. Further Reports (No. 3) on Flies as Carriers of Infection. f The signs made use of in the previous paper (for explanation see p. 18) are letained for indicating the results of cultures from infected flies, etc.