Atlantic City, N. J., April 29, 1921. 

 FRIDAY MORNING SESSION. 



(The meeting was called to order at 10.30 A. M. by President 

 Rider). 



President Rider : The meeting will come to order. The first on 

 the program this morning is "Symposium on the 1920 work of mos- 

 quito control and its results." The time is marked here on the pro- 

 gram to be limited to ten minutes. We will first hear from Hudson 

 County, Mr. Lewis E. Jackson, Executive Secretary, Hudson County 

 Mosquito Extermination Commission. 



The problems encountered in mosquito control work in Hudson 

 County during the season of 1920, the commission's eighth year of 

 operation, on both the salt marsh and upland, did not differ mater- 

 ially from those met with in previous years. 



As to methods employed, there can be but few essential changes 

 in those having become more or less standard in each class of work 

 through our state through numerous years of combat with the mos- 

 quito which pursues its life habits along very much the same lines 

 year after year, unchanged even by constitutional amendments. 



The commission has continued the cutting of new ditches in the 

 salt marsh where required to provide permanent drainage systems, 

 and the cleaning of systems previously installed to maintain their 

 efficiency. The commission's present policy in installing new sys- 

 tems is to employ ditches of greater width with increased distance 

 between them where the porosity of the soil will permit and to widen 

 some of the old ditches. The width of ditches and the plan upon 

 which they are installed, of course, depends upon local conditions 

 in each section treated but the commission is getting away from the 

 ten-inch ditch, the main reason, in addition to that of the limited 

 flow of the narrow ditch, being that it readily becomes blocked, thus 

 defeating the purpose for which it is planned and entailing a prohibi- 

 tive maintenance cost. 



All the ditches cut last season were thirty inches in width. The 

 prevailing standard depth of thirty inches has been maintained, it 

 having been found that the marsh of Hudson County drains readily 

 without the increased depth often contended as necessary. Under 

 conditions existing at present, I know of no section of the Hudson 

 County marsh requiring ditches of a greater depth than thirty inches. 



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