194 THE HOUSE FLY— DISEASE CARRIER 



whether it would be possible to treat a manure pile in 

 such a way as to stop the breeding of flies. Previous 

 experience with the use of air-slaked lime on cow 

 manure to prevent the breeding of the horn fly sug- 

 gested the experimentation with different lime com- 

 pounds. It was found to be perfectly impracticable 

 to use air-slaked lime, land plaster, or gas lime with 

 good results. Few or no larv^ were killed by a thor- 

 ough mixture of the manure with any of these sub- 

 stances. 



Chloride of lime, however, was found to be an ex- 

 cellent maggot-killer. Where one pound of chloride 

 of lime was mixed with eight quarts of horse manure, 

 ninety per cent, of the maggots were killed in less than 

 twenty-four hours. At the rate of a quarter of a pound 

 of chloride of lime to eight quarts of manure, however, 

 the substance was not sufficiently strong. Chloride of 

 lime, although cheap in Europe, costs at least three and 

 one-half cents a pound in large quantities in this coun- 

 try, so that frequent treatment of a large manure pile 

 with this substance would be out of the question in ac- 

 tual practice. Moreover, if the manure receptacle is in 

 the stable where horses are kept, or in close proximity 

 to it, the chlorine fumes arising from a pile thus treated 

 would be an irritant to the eyes of the live stock. 



After these experiments with lime, kerosene was 

 used. It was found that eight quarts of fresh horse 

 manure sprayed with one pint of kerosene which was 

 afterwards washed down with one quart of water was 

 thoroughly rid of living maggots — every individual 



