IDfi 3[0SQnT()ES 



it t'ri'e from orj?anie matter for thirty days, at a po.st of 2") cents ; 

 tliat with care a whole state may be kept free of insect pests at a 

 small cost. An efficacious method is to scatter a few crystals 

 widely ai)art. A single pinch of permanganate has killed all the 

 germs in a 1,000-gallon tank. 



The item is so obviously ridiculous upon its face that 

 it would hardly seem woitli while to make any attempt to 

 refute its statements. Nevertheless, it has been so widely 

 read that detiuite experimentation seems necessary to set 

 the matter at rest. The unknown author's ignorance of 

 the life history of mostjuitocs in the opening" sentence 

 need not necessarily imply that he would not know a g^ood 

 remedy if he found one. Careful experiments were under- 

 taken by the writer in July, 1898, with various strensrths 

 of perman^-anate of potash, in water containing]: mosquito 

 larvju fr(nn one to six days old. It was found that small 

 amounts of the chemical had no effect whatever upon the 

 larvie, which were, however, killed by usin.s:: amounts 

 so lari;-e that, instead of using- a " handful to a ten-acre 

 swamp," at least a wagon-load would have to bo used 

 to accomplish any result. Moreover, after the use of 

 this large amount and after the larvje were killed, the 

 same water, twenty-four hours later, sustained freshly 

 hatched mosquito larvjiB perfectly, so that even were a 

 person to go to the prohibitive expense of killing mos- 

 quito larv5\3 in the swamp with i)ermanganate of potash, 

 the same task would have to be done over again two days 

 later. 



The same conclusion was subseqmmtly reached, after 

 careful experiment, by Dr. Lederle, of the New York 



