CARRIAGE OF DISEASE 145 



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. L, by Prof. G. F. Sykes (1910), of Brown 

 University. The conclusions reached by him were as 

 follows: (i) 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 domestica, the remaining frac- 

 tional per cent, being Lucilia cccsar, (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 



