FLEAS AND THEIR CONTROL. 13 



salt should be scattered about and thoroughly wet down. A second 

 wetting two or three days later usually will accomplish complete 

 destruction, but if this is not found sufficient, one or two additional 

 wettings may be given. Where crude petroleum is cheap and espe- 

 cially where Avater can not be applied easily, sprinkling the ground 

 with a liberal amount of this oil will give good results. The free 

 use of lime on the cleaned areas also apparently destroys many im- 

 mature fleas. In exceptional cases lawns become infested, and fleas 

 breed out around the roots of the grass. It is impracticable to apply 

 chemicals in such situations, but much may be done to check the 

 breeding by cutting the grass exceedingly short and thus exposing 

 the young fleas to the heat of the sun, which will usually accomplish 

 their destruction. In certain sections it has been found feasible to 

 destroy flea infestations in barns and hog runs by diking the in- 

 fested areas and pumping water in so as to flood them entirely. 



TRAPPING FLEAS. 



Following the treatment of host animals and the thorough clean- 

 ing up of the premises, as has been outlined, many of the remaining 

 adult fleas may be caught by the use of traps. 



There seems to be some virtue in the use of lights at night for at- 

 tracting the adult fleas. A small lamp set in a pan of water covered 

 with a film of kerosene may be used for this purpose. 



It has been found that a considerable number of fleas may be col- 

 lected about a room or cellar by allowing an animal such as a guinea 

 pig or cat to be free in the room. The fleas thus concentrated on the 

 animal may be destroyed by the methods mentioned under "The 

 destruction of fleas on cats, dogs, and hogs." In districts where the 

 plague is known to exist and it is desirable to catch the few fleas 

 which ma}^ be about the premises, this method is of some value. 



ISOLATING AND REPELLING. 



It has been determined that the greatest horizontal distance fleas 

 can jump is about 13 inches, and they can not jump more than one- 

 half of this distance vertically. It is possible, therefore, to prevent 

 them from gaining access to a bed by placing sticky fly paper about 

 13 inches wide on the floor around the bed, provided fleas are not 

 breeding out under it. It is also possible to keep fleas out by placing 

 the legs of the bed in pans of water covered with a film of kerosene, 

 if the bedding is prevented from reaching near the floor 



Many different substances have been advocated as repellents for 

 fleas. Among these may be mentioned such plants as pennyroyal 

 and boughs and chips of pine. Naphthalene crystals and pyrcthrum 

 have also been employed for dusting between the sheets in order to 



