2o6 The Control of Mosquitoes 



authorities, who are more competent to judge 

 the importance of the defects deemed unworthy 

 of attention by the average layman, builder, and 

 architect. 



In a malarious locality the screening of dwellings 

 is a necessity. With a view to determining as 

 nearly as possible the difference in malaria infec- 

 tion between the inhabitants of screened and 

 unscreened dwellings at Gatun, a study was made 

 by. Dr. Orenstein. The conclusions reached were 

 that screened dwellings reduce the malaria inci- 

 dence by at least one third. 



It is almost certain that the protection afforded 

 is greater than this study showed, for the reason 

 that while the people residing in the screened 

 quarters of Gatun were obliged to consult a govern- 

 ment physician when incapacitated for duty by 

 illness, the residents of the unscreened section 

 were not required to adhere to this rule, and con- 

 sequently there is no record of a probably large 

 number of cases from these houses. 



INFORMATION CONCERNING METALLIC MOSQUITO 

 SCREENING 



1 6 mesh copper aUoy gauze will permit the 

 passage of Aedes calopus only under stress of 

 circumstances. 



