Proceedings of Eighth Annual Meeting 37 



great number found within some districts is such a menace to the 

 comfort of the residents that it cannot be neglected, if we desire to 

 keep mosquito annoyance below the point of complaint. Inspection 

 and advice may remove them temporarily, but usually the original 

 conditions may be found within a few weeks, when a second visit 

 is made. This makes backyard inspections in these sections neces- 

 sary. I believe this method of control work was responsible for the 

 great reduction in pipiens annoyance that we enjoyed during 1920. 



Another important part of mosquito control in large cities is found 

 in and about manufacturing plants of which we have about a thous- 

 and, such as silk dyeing and finishing works, in whose grounds or 

 yards are usually found unused or discarded dye vats, barrels and 

 other containers holding water. To prevent pipiens breeding in or 

 about these plants, inspection is absolutely necessary. 



To get results our efforts must be directed against breeding places 

 of any kind, wherever found, if we hope to make mosquito control 

 work successful. This can be done only by intelligent inspection in 

 those parts of large cities where unsanitary conditions usually pre- 

 vail. There seems to be some difference of opinion in various 

 counties as to the value of backyard inspection in mosquito control 

 work. Some counties have partly abandoned yard inspection, and 

 give as the reason that publicity of anti-mosquito work has been so 

 convincing that people have destroyed their pet rainbarrels and cov- 

 ered the open cisterns. Backyard inspections thus became just so 

 much lost motion and the cost of such inspection could be devoted 

 to more important features of the work. This plan may be advis- 

 able where the population is much scattered and the dominant fea- 

 ture of mosquito control is the elimination of salt marsh species. 

 However, we could not make this plan fit Passaic County, especially 

 in cities like Paterson and Passaic, where the density of population, 

 as above stated reaches 17,000 to the square mile, and there are a 

 thousand manufacturing plants of various kinds, whose owners fail 

 to recognize the economic value of mosquito control work. 



Passaic River 



The problem of controlling mosquito breeding on that part of the 

 Passaic River above tide-water and north of the Dundee Dam, I have 

 discussed many times in past years. It presents an area of three 

 hundred and fifty acres of which every inch is a potential breeding 

 spot. The rich organic matter from the sewage sludge and the slug- 

 gish flow furnish what might be called an immense open cesspool. 



