10 



FARMERS BULLETIN 851. 



voided, not only in the excrement of the fly, but also in small droplets 

 of regurgitated matter which have been called "vomit spots." 

 When we realize that flies frequent and feed upon the most filthy- 



substances (it may be the excreta 

 of typhoid or dysentery patients 

 or the discharges of one suffering 

 from tuberculosis), and that sub- 

 sequently they may contaminate 

 human foods with their feet or ex- 

 creta or vomit spots, the necessity 

 and importance of house-fly control 

 is clear. 



In army camps, in mining camps, 

 and in great public works, where 

 large numbers of men are brought 

 together for a longer or shorter time, 

 there is seldom the proper care of 

 excreta, and the carriage of typhoid 

 germs from the latrines and privies 

 to food by flies is common and 

 often results in epidemics of typhoid 

 fever. 



And such carriage of typhoid is 

 by no means confined to great tem- 

 porary camps. In farmhouses in 

 small communities, and even in 

 badly cared for portions of large 

 cities, typhoid germs are carried 

 from excrement to food by flies, 

 and the proper supervision and 

 treatment of the breeding places 

 of the house fly become most im- 

 portant elements in the prevention 

 of typhoid. 



In the same way other intesti- 

 nal germ diseases, such as Asiatic 

 cholera, dysentery, and infantile 

 diarrhea, are all so carried. Thero 

 is strong circumstantial evidence 

 also that tuberculosis, anthrax, 

 yaws, ophthalmia, smallpox, tropical sore, and the eggs of parasitic 

 worms may be and are carried in this way. Actual laboratory proof 

 exists in the case of a number of these diseases, and where lacking is 

 replaced by circumstantial evidence amounting almost to certainty. 



FIG. 12. The house centipede (Scutigeraforceps) 

 Adult. Natural size. (Marlatt.) 



