13 



Fumigation. — In addition to the hydrocyanic-acid gas treatment 

 noted above, two or three other forms of fumigation may be employed 

 against house roaches. Wherever roaches infest small rooms or apart- 

 ments which may be sealed up nearly air-tight, and also on shipboard, 

 the roach nuisance can be greatly abated by the proper use of poisonous 

 gases, notably bisulphid of carbon. This substance, distributed about 

 a pantry or room in open vessels, will evaporate, and, if used at the 

 rate of 1 pound to every 1,000 cubic feet of room space, will destroy 

 roaches. Unless the room can be very tightly sealed up, however, the 

 vapor dissipates so rapidly that its effect will be lost before the roaches 

 are killed. The hatches of ships, especially of smaller coasting ves- 

 sels, may be battened down, a very liberal application of bisulphid of 

 carbon having been previously made throughout the interior. If left 

 for twenty-four hours the roaches and all other vermin will unquestion- 

 ably have been destroyed. In the use of this substance it must be 

 always borne in mind that it is violently explosive in the presence of 

 fire, and every possible precaution should be taken to see that no fire is 

 in or about the premises during the treatment. It is also deadly to 

 higher animals, and compartments should be thoroughly aired after 

 fumigation. 



A safer remedy of the same nature consists in burning p3'rethrum in 

 the infested apartment. The smoke and vapors generated by the 

 burning of this insecticide are often more effective in destroying roaches 

 than the application of the substance in the ordinary way as a powder. 

 There is no attendant danger of explosion, and the only precaution 

 necessary is to see that the room is kept tightly closed for from six to 

 twelve hours. The smoke of burning gunpowder is also very obnoxious 

 and deadly to roaches, particularly the black English roach. On the 

 authority of Mr. Theo. Pergande, gunpowder is commonly used in Ger- 

 many to drive these roaches out of their haunts about fireplaces. The 

 method consists in molding cones of the moistened powder and placing 

 them in the empty fireplace and lighting them. The smoke coming 

 from the burning powder causes the roaches to come out of the crevices 

 about the chimney and fire bricks in great numbers, and rapidly 

 paralyzes or kills them, so that tliey may be afterwards swept up and 

 destroyed. This remedy will onl}' apply to old houses with large fire- 

 places, and has no special significance for the modern house. It is 

 presented, however, as a means applicable wherever conditions similar 

 to those described occur. 



Trapping. — Various forms of traps have been very successfully 

 employed in England ami on the Continent of Europe as a means of 

 collecting and destroying roaches. These devices are all so constructed 

 that the roaches may easily get into them and can not afterwards 

 escape. The destruction of the roaches is effected either by the liquid 



[Cir. 51] 



