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days later find that the barrel was neglected and mosquitoes 

 issuing from; it. 



The writer knows of no condition which cannot be overcome 

 and the breeding stopped. In Newark there are a number of 

 tanneries, in the vats of which mosquitoes breed. The owners 

 are opposed to having them oiled, claiming the oil would affect 

 the hides. This is overcome by the use of naphtha, which kills 

 the larva and evaporates. Another instance is a pond, the water 

 of which is used by a paper mill. This pond is a bad Anopheles 

 breeder, and the mill owners claim the oil would get into the 

 vats and spoil the paper. To overcome this objection we use 

 gasoline, which also evaporates, the owner paying part of the 

 cost. 



In oiling pools it is important that every inch of water surface 

 is reached, especially where there is an accumulation of growth. 

 Better work can be accomplished with a sprayer, but those doing 

 the oiling should not be averse to wading through and splash- 

 ing the water, thus enabling the oil to work over the entire sur- 

 face. 



While the prime object of a campaign of mosquito control 

 should be to find and do away with all standing water, it is neces- 

 sary to use oil or larvicide to keep down the breeding pending 

 other treatment. The expense of frequent oiling due to the rapid 

 evaporation of the oil should lead those engaged in the work to 

 look for a substitute for oil which would have the same effect 

 but be impervious to the sun. It is to be hoped that experiments 

 in this direction will be attempted. 



To the extra cost of larvicide as compared with oil and the 

 danger of it coming into contact with people, domestic animals 

 and fowl may be assigned the limited use of this material by the 

 writer. Larvicide may prove helpful in sparcely populated sec- 

 tions where it is too expensive to drain and where the conditions 

 will not permit oil to readily spread. 



Fish are valuable assets in some phases of mosquito control, 

 but it might be advisable not to place too much reliance in them, 

 as, for some reason which I am unable to explain, during the 

 height of the breeding season, for a brief period, the fish seem 



