20 N. J. Mosquito Extermination Association 



trouble, because the effluent was strong enough to acidify the 

 water of Redroot Creek and make it uninhabitable for mos- 

 quito larvae as well as for the small killifish. 



As you' know the uinderlying' principle of controlling salt-marsh 

 mosquitoes is the turning of one great natural force against an- 

 other; the turning of the killihsh or salt minnows against the 

 mosquito larvae on the salt marshes. 



After the Nixon Nitration Works, ceased operations for a 

 time during the summer, we found that the mosquitoes were 

 breeding in. Redroot Creek and all the branches thereof and on 

 the meadow that it drained. At the same time we could find not 

 a single killifish anywhere through that section; yet when one 

 went outside of that section one found an abundance of killifish. 

 Obviously, the slight amount of acid was not quite sufficient to 

 prevent the mosquito wrigglers from breeding. 



It was found by experiment that even the faintest trace of 

 acid, a trace so slight that ordinary chemical reagents for detect- 

 ing acidity would show no' acid, was sufficient to repel the fish. 



We built some long tanks and filled them with salt-marsh 

 creek water. Fish were placed in them;. Just a trace of acid was 

 dropped into one end of one of these tanks. Fish, which were 

 swimming normally back and forth in the tank, all promptly 

 swam to the other end and stayed there. 



It then became necessary tO' find out how this acid problem 

 should be met. We tried neutralizing the acid with lime. We 

 used ground limestone. We found that neutralizing the acid in 

 this way and dropping it into a hitherto untreated tank, at ten 

 times the strength used in the first experiment, did not drive the 

 fish to the other end. In fact, the fish seemed unaware that there 

 was any material going into the tank. Their normal activities 

 were not disturbed in the least. We believe that we have found 

 the way to eliminate the undesirable results of this acid effluent. 

 We believe that running this effluent over limestone, or discharg- 

 ing into it milk of lime, will so neutralize the acid as to do away 

 with the injurious effect. We will admit without any hesitation 

 at all that this conclusion is based solely upon laboratory experi- 

 mental results, and that when put into practice out-of-doors it 

 may not work. 



