390 A MANUAL OF BACTERIOLOGY 



The ordinary domestic fly, the blue-bottle and other similar flies 

 (of which there are many) have no biting proboscis, but undoubtedly 

 directly convey infection to food, etc., by carrying organisms upon 

 various parts of their body, or by the organisms passing through 

 the digestive tract and infecting the food with the faeces. In tin's 

 way, typhoid, bacillary dysentery, B. enteritidis, summer diarrhoea, 

 cholera, and possibly anthrax, and also the ova of certain worms, 

 may be conveyed. 



The ordinary house-fly breeds in dung and garbage containing 

 dung, and it has a possible range of flight of about a mile. The 

 house-fly experimentally infected remains grossly infected for at 

 least three days, and a smaller degree of infection persists for ten 

 days or even longer. 1 



1 Sec Reports to the Loc. Gov. Board on Flies as Carriers of Infection, 

 Nos. 1-4, 1910 and 1911. Martin, Brit. Med. Jovrn., 1913, I., p. 1. 



