Real understanding of the place of flies as vectors of disease probably dates from the report of the Typhoid Commission of 1898. Thus Vaughan,1 who had been one of the members of this commission, states that typhoid was less frequent among those who ate in screened mess rooms than among those who took their food in unprotected quarters. Flies were found swarming over infected fecal matter in the latrines and the same ones visiting and feeding on the food prepared for the soldiers in the mess tents. Now it is generally recognized that the house fly also plays a part in the distribution of conditions other than typhoid.
The exact rôle of the common fly as a carrier of disease probably varies greatly in different localities. A recent report by Parisot and Fernier2 is significant in this connection. Their particular interest in the subject arose from the fact