244 SUNSHINE AND SPORT IN 



jointly been responsible for so much of its bad 

 reputation in the past. If these pestilential agents 

 of sickness were as enterprising as the Southern 

 Express Company, the problem of their suppres- 

 sion would be such as to baffle all the resources 

 brought to bear on it. Fortunately for the human 

 race, heir to all the ills they carry about with them, 

 these gnats live their mischievous lives within a 

 very limited area, flying (unless borne by the wind) 

 but a little distance from their watery birthplace. 

 It is therefore practicable to eradicate them, so far 

 as the dissemination of disease by their agency is 

 concerned, for a clear radius of five hundred yards 

 round human dwellings is probably sufficient to 

 insure immunity from their attacks. Of exterminat- 

 ing Stegomyia in every remote district of the 

 Isthmus there is no hope or need. The work 

 taken up by Colonel Gorgas and his assistants is 

 very thorough, embracing street cleaning (on the 

 principles that answered so successfully in the city 

 of Havana), whitewashing houses, the free distri- 

 bution of pure water, and actual warfare on the 

 mosquito. This campaign against a small and 

 irreconcilable foe includes the cleaning out of 

 tanks, wells, cisterns, calabashes and any and 

 every likely breeding-place, filling up ditches with 

 great stones so as to make it impossible for stag- 

 nant water to lie anywhere, oiling such water as 

 cannot be got rid of by placing over it five-gallon 

 barrels that drip slowly on the surface, or even im- 

 pregnating it with copper sulphate, which kills the 

 algae that afford cover for the larvae of Anopheles. 

 Native huts are fumigated with sulphur and pyre- 

 thrum, gutters are closed, crab-holes (favourite 



