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JAMA. 1903;XLI(1):39. doi:10.1001/jama.1903.04470030043016.
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The extinction of malaria is one of the great medical questions of the day, and it is only natural that active minds should constantly find new points bearing on this subject. One of the latest suggestions is that given by Dr. Arthur R. Waddell in the Lancet, June 6. In experiments on the destruction of mosquitoes and mosquito larvæ he was impressed with the observation that very minute quantities of ammonia were decidedly fatal to these insects. Using strong liquor ammonia as a standard, a solution of 1 in 4,000 proved absolutely fatal for mature larvæ, and a solution so much weaker killed immature larvæ that he made the calculation that 1 in 20,000 or 30,000 would be sufficient to make water uninhabitable for them. His experiments indicated that ammonia is poisonous to mature larvæ in all its combinations. This suggested to him the fact that the nitrification of the


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