IRRIGATION 



It is quite commonly asserted that malaria makes 

 its appearance together with irrigation. This is evi- 

 dently true, but it need not be so if proper attention 





$2 



Sw §1 





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Fig. 2g. Breaks in the irrigation ditch are responsible for considerable inundation, 

 producing favorable breeding places for Anopheles mosquitoes. The rapidly running 

 water in the ditch is unfavorable for mosquitoes. 



were paid to the best methods of irrigation. Cer- 

 tainly southern California is necessarily the scene of 

 much irrigation, yet malaria is virtually unknown, so 



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