USE OF GASES AGAINST HOUSEHOLD INSECTS 443 



on dry food products, like bread, crackers, cakes, meats, 

 and similar materials. In fact, some experiments per- 

 formed by R. Harcourt at the Ontario Agricultural 

 College showed that flour fumigated with hydrocyanic 

 acid gas made just as good and, in some instances, appar- 

 ently better bread than the normal flour. On the other 

 hand, wet food-stuffs like butter, milk, and cream are liable 

 to absorb some of the gas and should be removed before 

 fumigation. 



The poisonous nature of the gas. There is, however, 

 one serious drawback to the general use of this gas. It 

 is one of the most poisonous substances known. It is a 

 deadly poison to all forms of animal life including man. 

 A few full inhalations of the gas will produce asphyxiation. 

 Moreover, the potassium cyanide, from which the gas is 

 derived, is a most virulent poison. A very little of it 

 accidentally eaten will produce death. This poisonous 

 quality of the cyanide and of the gas militates against the 

 use of the latter as a universal and general insecticide 

 and it necessitates great care and precaution in handling 

 the materials. 



Notwithstanding the poisonous nature of the gas and 

 the cyanide, we do not believe any careful, thoughtful 

 person should be deterred from employing this method of 

 controlling household pests. The writer has used over 

 340 pounds of the cyanide and fumigated over 250 rooms 

 every year for several years without the slightest accident 

 to any one connected with the work. The nature of the 

 gas demands calm, thoughtful, and orderly methods of 

 work. 



The greatest care must always be exercised in fumigating 

 houses or rooms that are being occupied. Before fumiga- 



