The House-Fly and Disease
BECAUSE the common house-fly is so potent an agent in spreading disease, many methods are suggested for its extermination. Dr. L. O. Howard, who stands at the head of the Department of Entomology in the United States Department of Agriculture, says: "The house-fly breeds only in fermenting organic matter. . . . The larvæ, moving in an excrementitious mass, accelerate putrefaction and help the spread of the putrefactive germs throughout the substance." Dr. John B. Smith, entomologist in the New Jersey Agriculturist Experiment Station, says: "The campaign is not so much against the fly as it is against the conditions which require the presence of the fly as a natural scavenger. . . . The fly is man's good friend and a necessity so long as man is a filthy animal. When he becomes a clean pig the flies will naturally disappear." Dr. C. Gordon Hewitt, dominion entomologist, Canada, puts it this way: "House-flies indicate the presence of refuse, garbage, and other insanitary conditions. The house-fly is useful therefore; it is of the greatest use as a danger-signal, as a 'red flag.' But we should not require danger-signals in such enormous quantities." Prof. S. W. Williston, of the University of Chicago, expresses himself to the effect that the fly is of domestic origin, that it does not exist apart from the insanitary conditions created by man. He points out that it is not found far removed from man's habitations. There are many places in the unsettled regions of the Rocky Mountains where a house-fly could not be found by hours of search. The same authority avers that thirty years ago the fly was unknown on the plains where it now exists in swarms. In summing up these facts Popular Mechanics says: "Thus it is not the fly which is primarily to blame for epidemics of typhoid fever and the like. It is man's segregation into cities and towns where he has not provided himself with the requisite sanitation. If the cause of the fly be removed, the fly will disappear, largely if not entirely, and the probability is that if in some miraculous way we could exterminate the fly without removing the cause, there would something worse speedily develop to take its place." The moral of all this is that the sanitary laws of cleanliness proclaimed by Moses, if they were carefully enforced, would rid the world of house-flies, and much of its troubles in the way of infectious diseases.