FUMIGATING HOUSES 63 



sulfuric acid, and four ounces of water. If cyanide of soda is 

 employed, use three ounces sulfuric acid. The cyanide should be 

 broken into lumps about two inches in diameter and placed in 

 manila paper bags. Workmen should use gloves. Water should 

 be placed in earthen crocks, large enough to prevent the liquid 

 from boiling over, the acid added, pouring it gently into the water. 

 The acid should never be poured into the jar before the water. 

 This crock is placed in the center of the room or box, the trees or 

 scions lying on racks above it. When everything is ready the 

 proper charge of cyanide contained in a paper bag is dropped 

 into the liquid and the box or room tightly closed. Exposure to 

 fumes should last about one hour, the fumigation chamber then 

 opened and allowed to air for fifteen minutes. Stock to be fumi- 

 gated should not be wet. Fumigation of nursery stock is far pref- 

 erable to "dipping." Where not practicable, however, stock may 

 be dipped in oil emulsion or lime-sulfur, avoiding wetting the roots, 

 or, better, it may be planted out and sprayed with these scalecides. 



The greatest care must be observed in handling this poison and 

 during the operation. In cleaning up, every particle of cyanide 

 should be accounted for, and all tools and utensils employed made 

 scrupulously clean. One should avoid inhaling the dust in break- 

 ing up the cyanide, and it should be kept out of sores or cuts in 

 the hands. (For the fumigating of mills with hydrocyanic acid 

 gas, see Chapter XVIII.) 



Fumigating Granaries and Grain Bins with Hydrocyanic Acid 

 Gas. This is described on page 353. It is useful if bins are empty. 

 For full bins carbon bisulfid should be used as directed under that 

 head. Both processes may be resorted to for the same building, 

 one following the other. 



Fumigating Houses with Hydrocyanic Acid Gas. This process 

 is very effectual against bedbugs, fleas and ants. At the same time 

 it is very dangerous, and every precaution must be taken to prevent 

 accident. It should not be resorted to if other effective measures 

 are available. The same general method is followed as given under 

 fumigation of mills. All polished metal must be protected, rugs 

 and carpets safeguarded against the boiling over or breaking of 

 jars, and the house must be left unoccupied during the fumigation 

 and ventilation. All moist foods should be removed. Fumigation 

 of one apartment of a double house or apartment house would be 

 attended with grave dangers to occupants of the other apartments. 

 As pointed out elsewhere, in working with this gas, one should 



