24 



A description of the methods and apparatus used during these 

 experiments is given, as the technique has been considerably improved 

 upon since those recently described [R.A.E., B, viii, 96]. 



Symposium on the Progress in Mosquito Work. — Proc. Fifth Ann. 

 Meeting, New Jersey Mosquito Extermination Assoc, Trenton, 

 1918, 116 pp. 1 plate. [Received 2nd December 1920.] 



This includes a number of reports from various counties of New 

 Jersey detailing the particular remedial measures suitable to the locality 

 that have been carried out. It is estimated by R. F. Engle that 9,000 

 acres can be added to the area of drained marshland, which already 

 comprised 95,000 acres in 1917, the drained areas remaining free from 

 infestation. The latest mechanical devices and ditching macliines 

 are described by H. I. Eaton. Thoroughness in ditching and draining 

 operations are considered the most essential factors in mosquito 

 eradication by E. Winship, who describes the drainage operations in 

 Greater New York. The necessity for organising a proper patrolling 

 force is emphasised. 



Young (D.). The Problem o£ Water Pollution in Relation to Mosquito 

 Control. — Proc. Fifth Ann. Meeting, New Jersey Mosquito Exter- 

 mination Assoc, Trenton, 1918, pp. 35-42. [Received 2nd 

 December 1920.] 



The purification of rivers and streams after years of gross pollution, 

 which has encouraged intensive mosquito breeding, is a difficult 

 problem, and is likely to require far more expenditure than the public 

 is prepared for. Frequently the discharge of sewage and manufacturing 

 waste-products into ponds, pools and streams, while increasing mosquito 

 breeding, has destroyed fish and other natural enemies. In studying 

 the question of purification it is necessary to determine the origin, 

 character and quantity of the pollution. The only existing method of 

 mosquito destruction in polluted waters is oil spraying, and this is 

 a temporary expedient, hmited in its effect on large areas, only 

 minimum results being obtained from maximum effort. There are 

 also many specific problems dependent upon the kind and condition 

 of the polluting material present. For example, the discharge 

 from tanneries of tannic acid, Hme and clay waste causes discoloration 

 and affects fish life. The spent lye discharged from soap works, and 

 nitric and sulphuric acid from ammunition and powder factories, 

 destroy all insect life and fish. Sewage-polluted streams, and even salt 

 water, seem to have a particular attraction for the female of Culex 

 pipiens, while they preclude the presence of the kilhfish that are 

 natural enemies of mosquitos. In water polluted with commercial 

 waste both C. pipiens and [Aedes] sylvestris have been found breeding 

 prolifically, the only remedies being frequent trimmings of the banks 

 of open sewers and the liberal use of crude oil. Sewage-polluted 

 meadow pools are more troublesome than fresh or salt water, for C. 

 pipiens appears in these much sooner after oil treatment than in fresh 

 or salt water pools. 



It is suggested that part of the responsibihty for river and stream 

 pollution rests with health officers, who frequently fail to enforce the 

 Board of Health ordinances and the State Sanitary Code enactments. 



The discovery of a larvicide of such a chemical character that it 

 would be harmless to plant life and to domestic animals and would 

 remain effective during the season, would be of the greatest advantage. 



