Proceedings of Seventh Annual Meeting 25 



very numerous and often very hard to find and since the maturing 

 of these snow-water mosquito larvae is very rapid. To treat all of 

 these pools over the surface of an entire mountain and in the course 

 of two weeks, as I attempted to do, is almost impossible. Very 

 many little, hidden pools will be overlooked, and thus many mos- 

 quitoes will escape to last on into the summer. 



The Eysell method of burning over in the autumn the fallen 

 leaves in such hollows where such pools will be formed the fol- 

 lowing spring from the melting snow-water would be dangerous in 

 a forested region where autumn fires are to be avoided. There is, 

 nevertheless, here an idea of great potential value. 



In 191 5 Carter and LePrince published their important studies on 

 impounded waters and their effects on the prevalence of malaria in 

 the United States. 



In 1 91 3 Mayor described a new mosquito-proof and storm-proof 

 house for the tropics. 



In 191 3 also Balfour, as the result of experiments at Khartoum, 

 recommended a special tincture of pyrethrum, soft-soap and glycer- 

 ine, diluted for use with twenty times its amount of water, as a larvi- 

 cide substitute for petroleum. 



In 1 91 4 Bacot announced the efficiency of naphthalene sprinkled 

 on the surface of water as destroying mosquitoes in covered cisterns 

 and wells. 



In 1916 Laveran described the mosquito-nets adopted by the 

 armies of the United States and Japan, considering the Japanese 

 the more effective. One of these nets consists of a cylinder of net 

 supported by two rings of steel about ten inches in diameter kept 

 apart by a spiral of the same metal. The upper part of the cylinder 

 is closed, and to the lower ring is attached a fold of cloth which can 

 be placed closely around the neck when the net is worn. It can be 

 folded up when not in use. 



In 1916 the Sergents in Algeria, having conducted anti-malaria 

 campaigns in Algeria since 1902, announced the control of anopheline 

 larvae in alternate drainage, alternating the outflow of the water each 

 week. Two drain channels instead of one must be made for each 

 spring, and during the summer one of these will be used for one week 

 and then dammed up while the water is allowed to flow into the other. 

 The disused one will dry up and the mosquito larvae in it will be 

 killed. At the same time these channels act as mosquito traps. By 

 applying this principle to irrigation, breeding places may be rendered 

 harmless without prejudice to agricultural requirements. 



