372 MOSQUITOES OF NORTH AMERICA 



" 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 5000 cubic feet. 



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



The 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 DIOXIDE. 



The damage done by sulphur dioxide 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 practically exclusively in the anti-mosquito 

 work during the yellow-fever outbreak of 1905 in the city of New Orleans. 

 Houses suspected of containing yellow-fever infection 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 flours 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 

 two pounds of sulphur for each 1000 cubic feet of space will be perfectly 

 efficient against mosquitoes and other insects. Sulphur candles may be used 

 where available. For an excellent account of certain careful experimentation 

 with sulphur, see an article by Passed Assistant Surgeon Francis, of the U. S. 

 Public Health and Marine-Hospital Service, published in Public Health Re- 

 ports, March 29, 1907, vol. xxii, No. 13, pp. 346 to 348. 



Writing of sulphur, Giles objects to pure sulphur fumigation on account of 

 the difficulty of burning it, and suggests a mixture of one part of nitre and 

 charcoal to eight of sulphur, the mixture being made up in pastilles weighing 

 four ounces each by means of a little gum water, dried in the sun. In India 

 he burned one of these pastilles for every thousand feet of space and found that 

 the effect was admirable, and that even in thatched buildings hardly a mos- 

 quito escaped. After fumigating, the floor of a bathroom in which hardly any 

 mosquitoes could be found was covered with dead mosquitoes, which indicates 

 not only the efficacy of the fumigant, but also the effectual ways in which the 

 Indian mosquitoes hide. He suggests that the fumigating should be done 

 towards the end of the hibernating season, and during the heat of the day, 

 when practically all of the mosquitoes are under shelter. He urges the adoption 

 of this method of fumigation in all government barracks, showing that each 

 pastille costs no more than one Lee-Medford cartridge, and that the annual bill 



