Page:Popular Science Monthly Volume 58.djvu/262

254 are rather carrion species. Other forms were taken, but either their household occurrence was probably accidental or from their habits they have no significance in the disease-transfer function.

It appears plainly that the most abundant species breeding in or attracted to dejecta do not occur in kitchens and dining rooms, but it is none the less obvious that while the common house-fly, under ordinary city and town conditions as they exist at the present day, and more especially in such cities and towns, or in such portions of cities as are well cared for and inhabited by a cleanly and respectable population, may not be considered an imminent source of danger, it is, nevertheless, under other conditions a factor of the greatest importance in the spreading of enteric fever.

The house-fly undoubtedly prefers horse manure as a breeding place. We have shown that it is not one of the most abundant species of flies breeding in or attached to human fæces, but, in the course of the observations made in the summer of 1899, we have definitely proved

the following facts relative to the house-fly, and in the statement of these facts it must be remembered that every specimen has been carefully examined by an expert dipterologist, so that there can be no mistake:

(1.) In the army camps the latrines are not properly cared for and where their contents are left exposed, Musca domestica will, and does, breed in these contents in large numbers, and is attracted to them without necessary oviposition.

Such observations were not made by the writer at the concentration camps of 1898, but were made at the summer camps of the District of Columbia Militia, during the summers of 1899 and 1900.

The contrast between the conditions here observed and those which existed at the great army camp at the Presidio, San Francisco, California, as observed by the writer through the courtesy of Surgeon General Sternberg and Colonel W. H. Forwood, surgeon in charge of the Department of California, in the late autumn of 1899, was most