SMUDGES AND FUMIGANTS. 37 



fumigate the room divide the cubic contents by 500, and the result will be the amount 

 of sulphur required in pounds. 



Take, for example, a room 15 feet long, 10 feet wide, and 10 feet high, we would 

 multiply 15 X 10 X 10, equals 1,500 cubic feet. Divide this by 500 and you will have 

 the amount of sulphur required, viz, 3 pounds. 



After a rigid series of experimental tests, Rosenau, of the U. S. Public 

 Health and Marine-Hospital Service, concludes that sulphur dioxid is 

 unexcelled as an insecticide. He shows that very dilute atmos- 

 pheres of the gas will quickly kill mosquitoes, and that it is quite as 

 efficacious when dry as when moist. He shows that it has surprising 

 power of penetrating through clothing and fabrics, and that it will 

 kill mosquitoes even when hidden under four layers of toweling in one 

 hour's time and with very dilute proportions. He states that 

 although this substance has long been disparaged as a disinfectant, 

 because it fails to kill spores, it must now be considered as holding the 

 first rank in disinfection against yellow fever, malaria^ filariasis, and 

 other insect-borne diseases. 



OTHER FUMIGANTS. 



In the early antimosquito work in European cities different sub- 

 stances were experimented with. Fermi and Lumbao in their out- 

 lined experiments recommend chlorin gas. These writers advise that 

 4 or 5 spoonfuls of chlorid of lime be placed in a dinner plate and that 

 from 5 to 10 cubic centimeters of crude sulphuric acid be poured upon 

 it. This liberates the chlorin gas, which kills the mosquitoes. The 

 same writers claim that the vapors of chloral act rapidly, killing mos- 

 quitoes in a few seconds. Celli and Casagrande in their early experi- 

 ments in Italy recommend a substance called larycith III, which is 

 probably a misprint for larvacide. This is dinitrocresol, a yellow 

 aniline color, which kills adult mosquitoes when burned in small quan- 

 tities. Formaldehyde gas was recommended in 1890, but has been 

 found to have almost no insecticidal value. 



Dr. John B. Smith® found that the powdered " jimson" weed {Da- 

 tura stramonium) can be burned to advantage in houses. He recom- 

 mends 8 ounces to fumigate 1,000 cubic feet of space. He states 

 that it should be made up by the druggist into an amount with niter 

 or saltpeter 1 part to 3 parts of Datura, so as to burn more freely. 

 He states that the fumes are not poisonous to human beings, are not 

 injurious to fabrics or to metals, and can be used with entire safety. 

 He suggests that it be burned in a tin pan or on a' shovel. 



A long list of fumigants is given by Celli in his work entitled 

 *' Malaria According to the New Researches," and this list has received 

 a critical review, which carries at the same time the results of certain 

 experimental work by Arthur J. Kendall, in Bulletin No. 1 of the 



a Bui. 216, N. J. Agr. Exp. Sta., p. 12, November 24, 1908. 



