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(4) If men are put in such a state that they cannot develop 

 malaria, even if bitten by mosquitoes, naturally malaria is con- 

 trolled. This it is attempted to do with immunizing doses of 

 quinine. 



The first two methods aim at control of the mosquito, the 

 last two of the human host. The first and third are community 

 methods, the second and fourth individualistic, but they overlap 

 in this respect. The methods working by control of mosquitoes 

 should especially appeal to you, and it is only to these that I am 

 going to refer this evening. 



Which is the best method? There isn't any best method; or 

 rather, each one of themi is best under certain conditions. Let 

 me explain : The first method, getting rid of mosquitoes, is abso- 

 lutely effective. It should be so theoretically, and it has been 

 proven at Port Said, Panama and a dozen places in the United 

 States, that if the production of Anopheles mosquitoes is con- 

 trolled, malaria is controlled or eliminated. And it is always 

 physically possible to control the production of these mosquitoes. 

 Why then should we consider any other method? Because it is 

 not everywhere that this production can be controlled with the 

 allowable economic limit. 



I need not with this audience go into the methods of con- 

 trolling Anopheles production. It is in principle the same that 

 you pursue for your Aedes, viz. : Destruction of breeding 

 places by (a) removing the water in which they breed by drain- 

 ing or filling, or (b) rendering it unfit for breeding by current, 

 oil, larvicides, fish, etc., or a combination of them;. It differs in 

 detail because the life history of the two species is quite dif- 

 ferent. Although not the only method of malaria control, and 

 in some cases not advisable this, the control of Anopheles produc- 

 tion, is the one depended on in most of the work hitherto done 

 in the South. Quite frequently with screening — itself an anti- 

 mosquito measure — as an adjuvant. In my opinion, v^henever 

 it is not prohibited by the cost, it is the method of election. It 

 has these advantages: 



(i) The maim work is done once for all and the upkeep is 

 usually small. 



