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394 C. GORDON HEWITT. 



of cleaning themselves, after which they were allowed to walk 

 over the films of media. Although we were unable to recover 

 B. typhosus the presence of B. coli was demonstrated. 

 B. coli was also obtained from flies obtained on a public tip 

 upon which the contents of pail-closets had been emptied; the 

 presence of B. coli, however, may not necessarily indicate 

 recent contamination with human excrement. Aldridge (I.e.) 

 isolated a bacillus apparently belonging to the paratyphoid 

 group from flies caught in a barrack latrine in India during 

 an outbreak of enteric fever. In appearance and behaviour 

 to tests it was very similar to B. typhosus. 



Although we are not certain yet as to the specific organism 

 or organisms which cause the intestinal disease known as 

 infantile or summer diarrhoea, which is so prevalent during 

 the summer months and is responsible for so great a mortality 

 among young children, I think we must consider the relation- 

 ship of M. domestica and its ally Homalomyia cani- 

 cular is to this disease epidemiologically similar to typhoid 

 fever. 



2. Anthrax. 



In considering the relation of flies to anthrax several facts 

 should be borne in mind. As early as the eighteenth century 

 it was believed that anthrax might result from the bite of a 

 fly, and the idea has been used by Murger in his romance 

 'Le Sabot Rouge.' A very complete historical account of 

 this is given by Nuttall (1899). Most of the instances in 

 support of this belief, however, that flies may carry the 

 infection of anthrax, refer to biting flies. As I have already 

 pointed out, M. domestica and such of its allies as H. 

 canicularis, C. ery throcephala, C. vomitoria, and 

 Lucilia cassar are not biting or blood-sucking flies. The 

 nearest allies of M. domestica which suck blood in England 

 are S. calcitrans, Hsematobia stimulans Meigen, and 

 Lyperosia irritans L. ; the rest of the blood-sucking flies 

 which may be considered in this connection belong to the 

 family Tabanidae, including the common genera Has ma- 



