220 The Control of Mosquitoes 



sick at the same time their actual earnings are 

 small. 



The rich lands in malarial sections of the tropics 

 cannot be economically developed without syste- 

 matic malaria control. It is no longer a question 

 of whether a corporation can afford to pay for 

 the necessary anti-malaria measures; it is now 

 admitted to be foolish to attempt development 

 without reasonable sanitary precautions. 



The preventive measures taken in the Canal 

 Zone cost less than one cent a day for each 

 person. 



During the reconstruction of the Panama 

 Railroad, in many camps we housed laboring 

 forces in outfit-cars siirrounded by extensive 

 swamps, where drainage or economic control of 

 mosquito life was impossible. By screening the 

 cars, and destroying Anopheles in them once a day, 

 the infection of laborers was prevented. Live 

 mosquitoes caught daily in the cars were examined 

 for parasites, but no infected specimen cotild be 

 found. These preventive measures had not been 

 attempted before, but can be applied again, and 

 the efficiency of our troops on the Isthmus, and 

 elsewhere, may be kept up to the standard. 



Large forces of men employed in commercial 

 enterprises may now be kept in good health where 



