68 



Insects and Disease 



of New York Harbor as a Menace to the Health by 

 the Dissemination of Intestinal Diseases Through 

 the Agency of the Common House-fly," he shows 

 graphically that the prevalence of typhoid and 

 other intestinal diseases is coincident with the 

 prevalence of flies, and that the greatest number 

 of deaths from such diseases occurs near the river 

 front where the open or poorly constructed sewers 

 scatter the filth where the flies can feed on it, or 

 along the wharves with their inadequate accom- 

 modations and the resulting accumulation of 

 filth. 



FLIES AND OTHER DISEASES 



Not only is the house-fly an important factor in 

 the dissemination of typhoid fever, but it has been 

 definitely shown that it is capable of transmitting 

 several other serious diseases. 



The evidence that flies carry and spread the 

 deadly germs of cholera is most conclusive. The 

 germs may be carried on the body where they will 

 live but a short time, or they may be carried in the 

 alimentary canal where they will live for a much 

 longer period and are finally deposited in the fly- 

 specks where they retain their virulence for some 

 time. Flies that had been allowed to contaminate 

 themselves with cholera germs were allowed ac- 

 cess to milk and meat. In both cases hundreds of 



