on Mosquito Extermination. 33 



or in the yard, where there are not many people around, as 

 this gas is a very dangerous one and I would rather do the 

 manipulation from outside. The best way in which to do 

 this is, after placing the receptacle containing the acid in the 

 car, lower the cyanide contained in a muslin bag by a cord 

 run through a transom. As far as the disinfection of houses 

 is concerned, sulphur is the best thing to use unless there are 

 fabrics that it would destroy. It should be used, one pound to 

 1,000 feet, and will kill the stegomyia and other species of 

 mosquitoes. Hydrocyanic acid gas is dangerous for use in a 

 house, except under very favorable conditions. Tobacco smoke 

 can also be used, but it is not a good agent; it will kill the 

 mosquitoes, but stains the fabric and leaves a very disagreeable 

 odor. Pyrethrum is an efficient agent, provided the mos- 

 quitoes are promptly brushed up and burned, as only a portion 

 are killed, the others being simply stupefied and will recover 

 in the fresh air. Used as above, it forms a desirable agent 

 in killing mosquitoes in houses, especially in thickly inhabited 

 districts. 



Chairman : We had expected to have with us to-day Dr. 

 Ernst J. Lederle, President of the Department of Health of 

 the City of New York. He has written a letter, which Mr. 

 Weeks w'ill read. 



New York, December 14, 1903. 

 Chairman Anti-Mosquito Convention: 



Dear Sir: — I regret very much that a promise of mine to 

 address the Connecticut State Board of Health in New Haven 

 on December i6th will prevent my attendance at the Conven- 

 tion over which you have been invited to preside. I know 

 that the occasion will be important and profitable, and beg 

 to assure you, and, through you, the other members of the 

 Convention, of the continued interest of this Department in the 

 work of mosquito extermination in this city and vicinity. I 

 am deeply sensible of the importance of united efifort in this 

 respect, and I doubt not that your interest in the matter will 

 lend to the movement the co-operation of the State of New 

 Jersey. 



