152 



THE COMMON HOUSE-FLY 



vigilant in the use of fly-screens, fly-traps, etc. During the 

 late war the late Professor Leidy pointed out, with bene- 

 ficent results, that the common house-fly was instrumental 

 in spreading the contagion of hospital gangrene. Why not 

 beware of this imprudent and ubiquitous little dipter in car- 

 rying and spreading the contagion of the dreaded Asiatic 

 plague now menacing us?" 



"During the months of August, September and October, 

 but mainly during September, it is a very common occur- 



Fig. 127. — Disease of house-fly. Greatly enlarged. 



rence to find dead house-flies adhering to the walls, window- 

 panes and other conductors of heat, firmly fixed by their 

 proboscis and with the legs spread out in quite an unnatural 

 manner, thus differing from dead flies in general which have 

 the legs contracted. In about t^venty-four hours after death 

 a kind of fatty substance of a white color is found in the 

 form of a ring projecting out between each of the rings of the 



