Results 225 



Devices for making wire screening continuously 

 efifective, together with systematic inspection 

 and repair. 



The complete eradication of mosquito-producing 

 conditions in hillside ditches and the elimination 

 of maintenance costs by the introduction of a 

 thin reinforced concrete lining of special design. 



The elimination of seepage water breeding areas 

 by the use of special methods designed to suit 

 local conditions, where standard methods of sub- 

 surface drainage were valueless. 



The use of automatic oil drips to control mos- 

 quito breeding in running water in streams and 

 ditches, and that of oil-soaked waste for small 

 see page outcrops. 



In describing the use of oil on the Isthmus Dr. 

 Malcom Watson, who has had extensive experi- 

 ence in measures for malaria eradication, and 

 directed the successful control of malaria in the 

 Federated Malay States, after inspecting the 

 methods used at Panama, reported to the Royal 

 Colonial Institute as follows : 



As the greatest sanitary achievement the world has 

 seen, it has a lesson for us. I went there because 

 I wanted to study the details of their methods, in 

 particular how much of their excellent results was 

 due to drainage, and how much to screening, oiling, 



IS 



