266 REPORT OF THE DEPARTMENT OF ENTOMOLOGY OF THE 
CHARACTBR OF HYDROCYANIC ACID GAS. 
Hydrocyanic acid gas may be generated by bringing cyanide of 
potassium in contact with sulphuric acid. It is colorless, has a 
faint odor of almonds, and when inhaled, unless largely diluted 
with air, is very dangerous. Much care should therefore be 
used in handling it. | 
CLASSIFICATION. 
The experiments were divided into two series. Series I 
included the experiments with uninfested buds and Series II the 
experiments with the hibernating scales. 
SERIES I. EFFECT OF THE GAS UPON BUDS. 
The following experiments with buds of a variety of fruits 
were undertaken to ascertain if possible whether bud sticks 
could be safely fumigated with the gas strong enough to kill the 
scale. The conditions were not entirely satisfactory as the 
treatment was somewhat delayed and the treated buds were not 
set in until the first week of August. This was out of season 
for most of the varieties. Also the treated buds were not set 
in until after the checks, which were budded at the proper time, 
and were placed about four inches above them where they were 
too high to be protected by the earth thrown against the trees 
during fall cultivation. In addition to this they were neces- 
sarily placed on the furrow sides of the trees thus endangering 
them to injury during cultivation. These unfavorable condi- 
tions must be in part, and probably in large part, the cause for 
the failure of the treated buds to set or grow, on the average, 
equally as well as the checks. 
