180 FUMIGATION METHODS 



the influence of the ga, and should not remain more 

 than two or three hours in gas of sufficient strength to 

 destroy animal life. 



Dry seeds. Only a few experiments have been 

 performed along this line, but probably a sufficient 

 number to determine the point in question, viz., 

 whether dry seeds treated with hydrocyanic acid gas 

 retain enough of the gas to make them injurious to 

 animal life. Grain was subjected to gas of different 

 strengths, and for longer or shorter periods of time, 

 varying from one to sixty days. Grains thus treated 

 were from time to time fed to mice that had been 

 caught without injury, and placed in glass cages so 

 that they could be observed constantly. The cages 

 were provided with an abundant supply of air and 

 water, and kept at ordinary normal temperature of the 

 laboratory where the mice had been living previous to 

 the beginning of the experiment. Occasionally the 

 mice began eating the grains as soon as they w r ere 

 placed within reach, but, as a rule, several minutes to 

 several hours elapsed between the time the grains were 

 taken from the hydrocyanic acid gas and the time they 

 were eaten by the mice, thus giving time for any gas 

 that remained in contact with the seed or that had 

 penetrated the seed-coat to escape into the amosphere. 



In one instance, for example, a mouse was fed one 

 dozen kernels of corn and three dozen grains of wheat 

 that had been for four and one-fourth days in an at- 

 mosphere containing gas from one gramme of potas- 

 sium cyanide per cubic foot. The mouse began eating 

 the grain at once, and at the end of twenty-four hours 

 had eaten the whole of five grains of corn and had 



