CARRIAGE OF DISEASE 
115 
been plotting the curve of typhoid prevalence, and on 
comparison it was found impossible to derive any dis¬ 
tinct connection between the two curves—such connec¬ 
tion as would be suggestive of cause and effect. 
During the summer of 1909 a series of investigations 
of a very similar character was carried on in Provi¬ 
dence, R. I., by Prof. G. F. Sykes (1910), of Brown 
University. The conclusions reached by him were as 
follows: (1) Fly nuisance is local. (2) Geographic 
distribution of pestiferous flies is determined by local 
sanitary conditions. (3) The seasonal distribution is 
conditioned by meteorological influences (temperature 
and sunshine). (4) Over ninety-nine per cent, of the 
flies caught were Musca dornestica, the remaining frac¬ 
tional per cent, being Lacilia ccesar. (5) The plotted 
curve for typhoid cases did not show a close relation 
to the fly curve, but did show a close parallel to the 
temperature curve. (6) The high-water mark for 
deaths from diarrhea antedated that for the fly season 
by fully three weeks, and followed from one to two 
weeks after a noticeable rise in temperature.. (7) The 
geographic distribution of typhoid cases over the city 
was largely independent of areas known as “unsani¬ 
tary” and as “fly centers.” 
It is to be mentioned that the flies caught by Pro¬ 
fessor Sykes were collected in three kitchens, the Wash¬ 
ington observations covering sixty-two stations. 
It is possible that Doctor Chapin, of Providence, the 
writer referred to in the editorial under consideration, 
was confirmed in his opinion by the result of Professor 
