The importance of preventing food infection through the agency of common house flies is just beginning to be appreciated. These insects are admirably adapted to convey infection from their great numbers and incessant activity, as well as their numerous feet, capacious intestines, their frequent evacuations, and disgusting habits of alighting and feeding upon sputum, manure heaps, and all animal discharges. When fed on tubercular sputum the bacilli have been discovered alive in their intestines, and cholera germs have been found adhering to their feet by which they are easily transported from a choleraic stool to a piece of bread or a raw fruit or vegetable, destined in turn to infect the first person who is unlucky enough to eat it. During the cholera epidemic in Hamburg Dr. Simmonds found comma bacilli in the intestines of flies in the post-mortem room where dead cholera patients were examined. The bacilli remained one and a half hour in the flies - time enough to be carried a long distance or to be widely distributed. When the matter is further investigated it will doubtless be shown that other kinds of infection are often spread by the medium of these vulgar pests. Ordinary pus infection is readily carried by flies.

In the hastily constructed camps of our troops in the Spanish-American War, and in those of the British soldiers in the Boer War, many cases of typhoid fever were traced to infection by flies that had access to the latrines in which typhoid stools had been emptied.