SMUDGES AND FUMIGANTS. 35 



A summary of Doctor Francis's experimental work follows: 



1. As compared with sulphur, pyrofume stands on an equal footing in price. 



2. Whereas the federal regulations require two hours' exposure to sulphur, pyro- 

 fume is eflScient against mosquitoes in one hour. 



3. While sulphur is injurious to metals, fabrics, paint, and colors, pyrofume leaves 

 them unchanged. 



4. Pyrofume is suitable for fumigating the engine rooms and cabins of ships, and 

 for cars and fine residences. 



5. In amounts necessary to kill mosquitoes it does not injure bananas. 



6. A person can walk about in a room full of fumes and can sleep without discomfort 

 in a room two hours after fumigation. 



7. It requires only five minutes to fumigate a large room of 5,000 cubic feet. 



8. The fumes are generated outside the room and conducted into it. 



These conclusions were favorable, but the substance has not been 

 taken up in the practical work of the Public Health Service on 

 account of the fact that special contrivances necessary for the best 

 application of the substance have not yet been perfected. 



SULPHUR DIOXID. 



The damage done by sulphur dioxid to household goods is the 

 principal objection to its use as a fumigant, but in the case of yellow 

 fever epidemics where absolutely thorough fumigation is necessary 

 it is the most reliable of all substances to use. It was used prac- 

 tically exclusively in the antimosquito work during the yellow-fever 

 outbreak of 1905 in the city of New Orleans. Suspected houses 

 were fumigated in the most thorough way. Every effort was made 

 to close all crevices in the rooms fumigated. Heavy paper was 

 pasted over all apertures, including cracks. This gas is obtained by 

 burning flowers of sulphur or lump sulphur in a small pot, fire being 

 started with alcohol. It should be used on a bright day, and pots 

 and polished metal and delicate things should be removed. It has 

 been found that 2 pounds of sulphur for each 1,000 cubic feet of 

 space will be perfectly efficient against mosquitoes and other 

 insects. Sulphur candles may be used where available.*^ 



Writing of sulphur, Giles objects to pure sulphur fumigation on 

 account of the difficulty of burning it, and suggests a mixture of 1 

 part of niter and charcoal to 8 of sulphur, the mixture being made up in 

 pastilles weighing 4 ounces each, by means of a little gum water, dried 

 in the sun. In India he burned one of these pastilles for every 1,000 

 cubic feet of space and found that the effect was admirable, and that 

 even in thatched buildings hardly a mosquito escaped. After fumigat- 

 ing, the floor of a bathroom in which hardly any mosquitoes could be 

 found was covered with dead mosquitoes, which indicates not only 



« For an excellent account of certain careful experimentation with sulphur, see an 

 article by Passed Assistant Surgeon Francis, of the United States Public Health and 

 Marine-Hospital Service, published in Public Health Reports, March 29, 1907, vol. 

 22, No. 13, pp. 346-348. 



