CHAPTER VIII 



ATTACK ON PROPAGATION AREAS BY FILLING 



IN beginning anti-malarial work near a village 

 '^ where this work has not been done before, 

 the filling of depressions, etc., that hold water 

 should be accomplished. These places may be 

 controlled by the application of oil or larvacides, 

 but this method is not as good, because the work 

 needs to be repeated at frequent intervals, and also 

 because the personal equation is involved and 

 some propagation areas may be left untreated suf- 

 ficiently long to produce one or more broods. All 

 small depressions that hold water, including cow- 

 hoof marks, badly cut-up land, wheel-track marks, 

 small ponds that cannot be drained satisfactorily, 

 and fiat lands that do not dry with sufficient 

 frequency to prevent the development of pupas 

 during the wettest periods, should receive atten- 

 tion. There is nothing to be gained by filling 

 depressions having such absorbent qualities that 

 they become dry before a brood of mosquito 



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