PLEAS. 27 



5 pounds of flake naphthalene over the floor, and closing the room 

 tightly for 24 hours. This remedy was found inexpensive, as the 

 naphthalene could be swept up and transferred to another room. 



Dr. Howard has called attention to the method of control used by 

 Miss Adele M. Fielde, who has had extended experience with fleas in 

 China. She states that it is possible to control the fleas there by 

 the use of alum. This substance is added to the whitewash or cal- 

 cimine used on the walls, paper is dipped in a solution of alum and 

 put under rugs and matting, and powdered alum is sprinkled on 

 carpets or other floor covering and swept in. It does not injure the 

 rugs or matting, but banishes the insects, according to Miss Fielde's 

 statements. 



In houses where vacuum cleaners are used at frequent intervals 

 the number of fleas coming from the floors may be reduced. In cases 

 of infested houses a thorough cleaning of the carpets and floors with 

 a vacuum cleaner, provided it is efficient, would largely mitigate the 

 pests. 



Fleas in different stages in dwellings or other buildings may be 

 destroyed by fumigation with sulphur fumes or hydrocyanic-acid 

 gas. Either of these f umigants, when properly handled, will destroy 

 the fleas, and has the advantage of killing the rats and mice as well. 

 The use of sulphur 1 is efficient and simple, but has the objection of 

 corroding metal and injuring plants. In fumigating, the infested 

 building should be closed up tightly and the sulphur weighed out 

 at the rate of 4 pounds to each 1,000 cubic feet of space. The sulphur 

 is piled up cone shaped in a pan or kettle, which is placed in a 

 larger pan or tub of water to avoid fire from the heat generated. 

 A depression should be made in the top of the cone of sulphur, a 

 little alcohol poured into it, and a match applied. Each room to be 

 fumigated should have a vessel, and large rooms should have two, 

 one located near each end. It is preferable to do all of the fumiga- 

 tion simultaneously. The rooms or building should be kept closed 

 for from 10 to 12 hours. Although this gas is not nearly so dan- 

 gerous to man as is hydrocyanic-acid gas, the rooms should be 

 thoroughly aired before entering them. The corrosive action of the 

 gas on metals and its effect on plants should not be overlooked. This 

 may be minimized by fumigating when the atmosphere is dry. 



Owing to the poisonous character of the ingredients used and the 

 deadliness of the gas generated, fumigation with hydrocyanic-acid 

 gas should not be undertaken without carefully reading the direc- 

 tions 2 for the operation, and then only by an experienced person. 



1 Marlatt, C. L. Sulphur dioxide as an insecticide. In U. S. Dept. Agr., Bur. Ent., Bui. 

 60, p. 139-146, 1906. 



2 Howard, L. O., and Popenoe, C. H. Hydrocyanic-acid gas against household insects. 

 U. S. Dept. Agr., Bur. Ent., Cir. 163, 8 p., 1912. 



