MILLS AND OTHER BUILDINGS 161 
poured upon it. The cyanide is afterwards dropped 
into the liquid, bag and all. The acid soon eats 
through the paper and a bubbling reaction follows, 
similar to that produced by placing a piece of red-hot 
iron in cold water. ‘This lasts a few moments only, 
or until the acid acts upon the cyanide. 
A cloud of white steam is almost instantaneously 
disseminated throughout the room or enclosure. The 
odor of this gas is decidedly that of peach pits, and is 
therefore easily detected. /¢ zs considered one of the 
most deadly poisons known to chemical science and ts cer- 
tain death to any animal inhaling it. If a person 
shouJd breathe his lungs full of it he would not live 
to know when he took his second breath, if he got it 
at all. Attention has been called to the dangerous 
character of the cyanide and this gas in each chapter, 
and the writer again cautions those who are interested 
in the subject to handle the material with great care. 
When so handled there is no danger whatever, and 
the results are satisfactory in every respect. The 
effects on animal life given in Chapter IV. should be 
carefully read in this connection. 
Resisting power of insecis,—After much experi- 
mental work and many practical tests, we have found 
that the most resistant insects infesting grain and 
manufactured products are destroyed when the gas is 
generated at the rate of 0.25 gramme cyanide per 
cubic foot of space enclosed. ‘The adults of the Med- 
iterranean flour moth, Aphestia kuehniella, the Angou- 
mois grain moth, Sztotroga cerealella, and the Indian 
meal moth, Plodia interpunctella, are destroyed readily 
with 0.12 to 0.15 gramme cyanide per cubic foot. The 
