36 PEEVENTIVE AND REMEDIAL WORK AGAINST MOSQUITOES. 



the efficacy of the fumigant, but also the effectual ways in which the 

 Indian mosquitoes hide. He suggests that the fumigating should 

 be done toward 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 for invaliding men who 

 have been educated to use the latter is so heavy that it would be well 

 to adopt any measure likely to diminish it. 



In the course of the admirable work carried on during the last six 

 years in Rio de Janeiro and which has achieved such brilliant results, 

 it has been found that sulphur dioxid has given the best results in the 

 disinfection of houses. Cruz has given the following account of the 

 methods used: 



The house to be disinfected was completely closed. Every opening or orifice where 

 gas might escape was sealed with gummed paper. The furniture, too, after being 

 thoroughly cleansed, is tightly closed. Metallic or gilded objects are protected with a 

 covering of vaseline. After the roof is covered over with canvas the garrets are opened 

 for the free access of sulphur gas. The canvas is fastened to the walls with lath. 

 Then sulphur is burned in proportion of 10 to 20 grams per cubic meter, being deposited 

 in several receptacles distributed about the house and kept clear of the floor. Each 

 receptacle should not contain more than 1 kilogram [2.2 pounds] in order to insure 

 complete combustion. In the vacant spaces under the roof the burning sulphur should 

 be placed in receptacles set into others containing water to avoid danger of fire. After 

 all the receptacles are placed, the workmen close up the only exit left open and" keep 

 the house thus sealed for not less than 2 hours. The heated air and that displaced by 

 the sulphur gas escapes through the crevices of the roof, but the mosquitoes are kept 

 in by the canvas covering. 



In the admirable fight against the yellow-fever mosquito in New 

 Orleans in the summer of 1905, the following directions for fumigating 

 with sulphur dioxid were given out by the health authorities : 



Remove all ornaments of metal, such as brass, copper, silver, and gilt from the room 

 that is to be fumigated. All objects of a metallic nature which can not be removed 

 can be protected by covering the objects tightly with paper, or with a thin coating of 

 vaseline applied with a brush. 



Remove from the room to be fumigated all fabric material after thoroughly shaking. 

 Open all drawers and doors of furniture and closets. 



The room should be closed and made as tight as possible by stopping all openings in 

 chimney, floor, walls, keyholes, and cracks near windows and doors. 



Crevices can be closed by pasting strips of paper (old newspapers) over them with 

 a paste made of flour. 



The sulphur should be placed in an iron pot, flat skillet preferred, and this placed 

 on bricks in a tub or other convenient water receptacle with about an inch of water in 

 the bottom. This is a precaution which must be taken to guard against accidents, as 

 the sulphur is liable to boil over and set fire to the house. 



The sulphur is readily ignited by sprinkling alcohol over it and lighting it. 



The apartment should be kept closed for two hours, and then opened up and well 

 ventilated. 



Note.— To find the cubic contents of the room, multiply the length of the room by 

 the width, and this total by the height, and to find the amount of sulphur necessary to 



