1 84 FUMIGATION METHODS 



containing hydrocyanic^cid gas from fifty-thousandths 

 of a gramme of potassium cyanide per cubic foot and 

 in much less time than when soaked for twenty-four 

 hours. 



Grains and other seeds soaked for twenty-four hours 

 and then left for seven days in an atmosphere of hydro- 

 cyanic acid gas will remain inactive while in the gas 

 and from seven to twelve days after removal, but will 

 eventually germinate to some extent if the strength of 

 gas used does not exceed fifty-thousandths of a gramme 

 of potassium cyanide per cubic foot, i.e. , hydrocyanic 

 acid gas is capable of holding seeds in an inactive state 

 for two weeks or longer without destroying their vital- 

 ity, even when the conditions are otherwise favorable 

 for germination. 



Damp grains and other seeds treated with hydrocy- 

 anic acid gas of any strength even for short periods of 

 time should not be used for food until several hours 

 after removing from the gas. The effect of the gas 

 eventually passes off and the grain may be eaten with 

 safety, although long exposure to the gas seems to 

 render it unpalatable. 



In the first experiments conducted by the writer, 

 where grain and manufactured products were stored, 

 the gas was generated at the rate of o. 10 to 0.12 

 gramme per cubic foot. Very satisfactory results were 

 secured, but further experiments showed that it was 

 better to use from 0.20 to 0.25 gramme per cubic foot 

 of space enclosed. It was found that a greater volume 

 of gas remained in the building for a longer time 

 where larger doses were used. At the same time no 

 deleterious effects were observed either in the manu- 



