138 THE HOUSE FLY DISEASE CARRIER 



Influence of Flies in the Carriage of Typhoid in Cities 



Much of what we have just written refers to the 

 carriage of typhoid by flies in encampments of troops 

 and, in such facts as we have given about the Spanish- 

 American War and the Boer War, to their effective 

 carriage in temporary camps. We have equally shown 

 their influence, however, at more or less permanent 

 army posts and the certainty of the inference under 

 these conditions is acknowledged by practically every 

 one. And the same free acknowledgment must be 

 made in the case of any emergency which calls together 

 for temporary purposes large bodies of men, engaged 

 on great public works, for example, as the Panama 

 Canal or the construction of great reservoirs, or in 

 mining camps. Any slight lack of care in the disposal 

 of excreta under such conditions almost invariably 

 brings about an outbreak of typhoid, and most often 

 by the carriage of the causative organism by flies. But 

 does the same thing hold for cities? The opinion of 

 a certain class of conservative medical men on this 

 point is well expressed in a recent editorial in the Jour- 

 nal of the American Medical Association, as follows: 



"It is sometimes easier to implant a new idea in the 

 human mind than to extract it or modify it when it 

 has once taken firm root. The notion that bad smells 

 from faulty sewers give rise to specific infections, such 

 as diphtheria and typhoid fever, or that piles of gar- 

 bage 'breed disease/ are cases in point. In the public 

 mind, methods of garbage disposal and elaborate 



