CARRIAGE OF DISEASE 143 



may be difficult to prove directly and to the laboratory 

 man that any certain percentage of typhoid cases are 

 caused in this way, but how much more difficult will 

 it be to prove that they are not? And is not a great 

 preponderance of such evidence as we have in favor 

 of the conclusion that house flies are great dangers even 

 in cities as well cared for as the best of our American 

 cities ? 



As to the "repetitious babble of sentiment in deal- 

 ing with flies/' is it not a mistake to apply such words 

 to a conscientious effort to warn the public of a danger 

 which surely exists under certain conditions and most 

 probably exists in all? 



It was stated in the editorial which we are consid- 

 ering that the intensive study of typhoid fever in Wash- 

 ington, D. C., which extended over several years yielded 

 no evidence that fly transmission had any noteworthy 

 share in typhoid causation in the city. This statement 

 was based largely upon the fact that the fever for the 

 most part was absent or rare in portions of the city 

 where the box-privy nuisance still exists (and it should 

 be stated that the health officer has every one of these 

 nuisances carefully marked on a map) and that an ef- 

 fort made during the summer of 1908 to ascertain 

 whether there was any relation between the curve of 

 typhoid increase and the curve of fly increase resulted 

 in apparent failure. 



The effort was undertaken by the Bureau of En- 

 tomology of the U. S. Department of Agriculture in 

 co-operation with the Public Health and Marine-Hos- 



