Page:Popular Science Monthly Volume 79.djvu/145

Rh windows or screenless doors in the same building. Add to these conditions dense ignorance on matters of hygiene, indifference and intolerance of being interfered with, together with the fatalistic spirit above referred to, and one realizes that conditions there are almost always ripe for an epidemic.

It is hardly necessary to dwell at length on the house fly, now known as the typhoid fly, as a factor in the spread of the disease from which it is named. The excellent work of Dr. Howard along these lines, as well as later investigations, has placed the responsibility of one means of dissemination of typhoid where it belongs, and, as you well know, although we should still have typhoid if the house fly did not exist, and in spite of the fact that other insects may well carry the germ, the house fly is so evidently the chief offender that the name, "typhoid fly," is a very proper one to call attention to the danger of its presence.

In the eighties the possibility of flies carrying disease germs was called to the attention of physicians and the public. In 1898 we find what is perhaps the first reference to observations on the house fly's frequenting typhoid excreta, and thence flying to food, and the statement that bacterial cultures were obtained from both fly tracks and fly specks. Closely following this, in 1899, came the outbreak of typhoid amongst our soldiers in camp at Porto Principe, and Major Reed's report to the War Department that the epidemic was due to flies. The public then began to turn its serious attention toward the fly question. In 1900 Howard's article, published in the Proceedings of the Washington Academy of Sciences, on "A Contribution to the Study of the Insect Fauna of Human Excrement," further emphasized the great danger from the presence of flies in the household, and, as the house fly is the most common fly in that locality, designated that insect especially as an enemy to health. Work of different observers along these lines followed rapidly enough, every year showing additions to the evidence against this common insect, and the campaign against it was inaugurated, but it was not until recently that, as significant of its habits, and in order to help in this battle, the name of "typhoid fly" was suggested and adopted by entomologists.

We know that it may carry typhoid germs on its feet, on the hairs over its body, and in its alimentary canal and that these germs may live and be potent for some time even after having passed through its intestine. We know, in view of recent work, that this fly not only breeds in horse manure, but also in human excrement and other forms of filth, and it is a matter of common observation that this insect frequents all kinds of pollution from which it may carry disease germs to human food. You will readily see then, from the description of the domestic conditions prevailing amongst the miners on the Iron Range,