APPENDIX 

 HYDROCYANIC ACID GAS AGAINST HOUSEHOLD INSECTS 



The following directions for fumigating with hydrocyanic acid 

 gas are taken from Professor Herrick's circular published by the 

 Cornell Reading Course: 



Hydrocyanic acid gas has been used successfully against house- 

 hold insects and will probably be used more and more in the future. 

 It is particularly effective against bed-bugs, and cockroaches, but 

 because it is such a deadly poison it must be used very carefully. 



The gas is generated from the salt potassium cyanid, by treating 

 it with sulfuric acid diluted with water. Potassium cyanid is a 

 most poisonous substance and the gas emanating from it is also 

 deadly to most, if not all, forms of animal life. The greatest care 

 must always be exercised in fumigating houses or rooms in buildings 

 that are occupied. Before fumigation a house should be vacated. 

 It is not necessary to move furniture or belongings except brass or 

 nickel objects, which may be somewhat tarnished, and butter, milk, 

 and other larder supplies that are likely to absorb gas. If the nickel 

 and brass fixtures or objects are carefully covered with blankets 

 they will usually be sufficiently protected. 



There may be danger in fumigating one house in a solid row of 

 houses if there is a crack in the walls through which the gas may find 

 its way. It also follows that the fumigation of one room in a house 

 may endanger the occupants of an adjoining room if the walls be- 

 tween the two rooms are not perfectly tight. It is necessary to keep 

 all these points in mind and to do the work deliberately and thought- 

 fully. The writer has fumigated a large college dormitory of 253 

 rooms, once a year for several years, without the slightest accident 

 of any kind. In order to fumigate this building about 340 pounds 

 of cyanid and the same amount of sulfuric acid were used each time. 

 In addition to this, the writer has fumigated single rooms and smaller 

 houses with the gas. In one instance the generating jars were too 

 small; the liquid boiled over and injured the floors and the rugs. 

 Such an accident should be avoided by the use of large jars and by 

 placing old rugs or a quantity of newspapers beneath the jars. 



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