EO ae net nt 
Igor | EFFECT OF HYDROCYANIC ACID GAS 245 
potassium, and should be kept in air tight cans or jars until ready 
for use. 
4 If the seeds were to be treated in the dry state, no moisture 
was added except what was used to dilute the acid, and this 
consisted of only a few cubic centimeters of water. On the 
other hand, if damp seeds were to be treated with hydrocyanic 
acid gas, they were first soaked for the desired length of time in 
water, and then placed on moist filter paper under the bell jar, 
which was lined with damp filter paper, thus providing for the 
seeds a moist atmosphere favorable for their germination. All 
the chambers, whether damp or dry, were kept in the general 
laboratory where a pretty constant temperature of about 18° C. 
was maintained. Further details in regard to methods can best 
| be made clear by referring to the accompanying tables and their 
descriptions. The materials used in these experiments con- 
| sisted for the most part of corn, wheat, beans, and clover seed. 
: Occasionally other seeds were used in addition to those men- 
| tioned, but these four were carried through all the experiments 
and may be considered as fairly representing the seeds of mono- 
cotyledonous and dicotyledonous plants. Under certain condi- 
tions some of the seeds used seemed to be more sensitive to the 
treatment to which they were subjected than the others, but in 
general the behavior of the seeds under the conditions used was 
| similar for all seeds under identical conditions, the difference 
being simply a matter of degree. In other words, if the effect 
of the treatment was to accelerate germination all the seeds ger- 
minated more quickly than under normal conditions, whereas if 
the effect of the treatment was to retard germination then all 
germinated less readily than under normal conditions, although 
| all seeds of the same kind did not germinate at the same 
| moment. 
The strength of hydrocyanic acid gas used in these experi- 
ments is stated in terms of the weight per cubic feet of space 
to be fumigated of the cyanid of potassium used in generating 
the gas. In fumigating nursery stock for the destruction of 
insect pests, as well as for fumigating mills, barns, etc., 0.25%" of 
