442 HOUSEHOLD INSECTS 



Since that time the gas has been used by many people in 

 different parts of the United States for the destruction of 

 various insects. The author has treated many single 

 rooms, entire dwelling-houses, and one large dormitory 

 building annually for several years with this gas. In 

 nearly every instance the treatment has been satisfac- 

 tory. Where it has not produced the desired result, it 

 has been due to defective calking of cracks and holes or 

 to a poor quality of chemicals. 



It should be said, however, that the susceptibility of 

 insects to the effects of this gas varies considerably. For 

 example, the snout-beetles, commonly known as weevils, 

 are much harder to kill with this gas than moths, butter- 

 flies, or bugs. In general, it may be said that the soft- 

 bodied insects succumb more readily to the effects of the 

 gas than do the hard-bodied ones, like the beetles. For- 

 tunately, most of the abundant and serious household pests 

 are soft-bodied insects and, therefore, are easily overcome 

 by the gas. In addition, the gas will kill rats and mice, 

 and it is said will always drive them out where they will 

 die in the open. 



Moreover, the gas is not inflammable or explosive. In 

 this respect it differs markedly from the vapor of carbon 

 bisulfide. Again, hydrocyanic acid gas does not bleach 

 the colors of wall papers, draperies, or other household 

 fabrics. In general, it may be said that the gas does not 

 attack metals or gilt on picture frames and furniture. 

 It will, however, slightly tarnish nickel fixtures in bath- 

 rooms. The effect seems to be very superficial, because 

 it is easily removed by wiping the fixtures with a cloth. 

 Indeed, if the fixtures are covered or wrapped with towels, 

 they will not be affected. The gas has no deleterious effect 



