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- 
