PERSEVERE 113 



The same thing occurred in Cairo. Mosquito migra- 

 tion will not affect in any way the work of clearing 

 towns, villages, or even parts of towns, of the insects. 

 But if once cleared, and the work is allowed to fail for 

 any reason, the mosquitos will surely return. At 

 Ismailia and at Port Said, if the mosquito brigades 

 stop work for a single week even now after several 

 years of continuous work mosquitos return. This 

 shows that it is not possible to exterminate mosqui- 

 tos ; they can only be reduced. But this reduction 

 can be made so efficacious that the insects become 

 reduced to a negligible quantity, and the fevers will 

 be exterminated. Therefore it is clearly the duty 

 of every one, wherever mosquitos exist, to start pre- 

 ventive measures against them, including those 

 of the domestic species, in that extent of district as 

 means will allow. Sooner or later the presence of 

 mosquitos will mean the presence of disease carried by 

 them, even if these do not exist already. 



After the mosquitos have been reduced to negli- 

 gible numbers, and the work is being well maintained 

 at a diminished cost, the moustiquiers may be em- 

 ployed as ordinary sanitary inspectors. They will be 

 well acquainted with the town, with all its houses, 

 will know the inhabitants, who in turn will know 

 them. They can then be utilised to report on in- 

 sanitary places, unhealthy shops and overcrowded 

 factories, dangerous trades, and can even notify 

 disease or cases of sickness. They will learn from the 

 servants which houses have sick tenants, and such 

 cases can be investigated early and dealt with 

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