Mosquito Remedies and Enemies 127 



cloth hung on the bed will keep mosquitoes at a 

 distance, and the efficiency continues for a long 

 time. 



Tobacco and punk sticks do very well in a general 

 way, but do not prevent the ankles being bitten. 

 Mosquitoes do not appear to like moth balls, or 

 naphthaline, and I have successfully used these, pow- 

 dered, in low shoes. Most of the mosquito cones on 

 the market contain naphthaline and pyrethrum. 



General Remedies. — It is better to permanently 

 eradicate the breeding places than to be continually 

 treating them ; over large areas constant oiling is 

 almost impossible, and, even if feasible, is more ex- 

 pensive in the long run. In the case of troublesome 

 marshes, the destruction of breeding places is the 

 only possible course. Dr. Smith says that ditches 

 from two to two and one-half feet deep, and six 

 inches wide, at intervals of from sixty to one hun- 

 dred feet, are best for an ordinary marsh. About 

 eighty per cent, of marsh land can thus be treated. 

 Where the marshes are too soft for the narrow ditches 

 to hold, wider ones must be dug. The object is to 

 prevent the formation of pools by rains or tides, 

 and all surface water should be removed by proper 

 drainage within forty-eight hours. Large holes in 

 the marshes should be filled unless big enough so 

 that fish can dwell there, but over large marsh 

 areas ditches are all that is necessary. Just enough 

 drainage to remove all surface water in forty-eight 

 hours is necessary; it need not be such as to fit the 

 land for agricultural or other purposes. A hole 

 twelve inches or so in depth will collect water drained 



