372 MOSQUITOES OF NORTH AMERICA 
“3, While sulphur is injurious to metals, fabrics, paint, and colors, pyrofume 
leaves them unehanged. . : 
“4, Pyrofume is suitable for fumigating the engine rooms and cabitis 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. 
“¥, 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. Jt 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. 8. 
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 
