Results 219 



Much valuable experience has been gained, 

 that will aid future anti-malarial campaigns, and 

 these newly devised methods of procedure and 

 the important discoveries made as the work 

 progressed will now make it possible for many- 

 sections of the tropics to develop their agricultural 

 and natural resources. 



Until now Aedes calopus and a few species of 

 Anopheles have prevented the Caucasian race 

 from settling and developing the tropics. In some 

 of the richest parts of the United States more 

 than fifty per cent, of the agricultural population 

 is infected with malaria. In some parts of the 

 tropics the malaria rate exceeds seventy-five per 

 cent, of the rural population, and the transmission 

 of infection often continues throughout the year. 

 Under such conditions can progress or social 

 development be expected? 



In South America there are parts of the sea- 

 coast, and even cities, to which laborers from the 

 hill-country cannot be induced to go. They 

 refuse a high rate of wage, and their reasons 

 and judgment are sound. In recent railroad 

 construction in Brazil, European laborers 

 would not remain in the company's employ 

 although paid an exceedingly high rate of wage. 

 Where eighty per cent, of the laboring force is 



