GREENHOUSE AND COLD FRAME FUMIGATION 137 
numerous insecticides, hydrocyanic acid gas was used. 
The work was placed in the hands of H. D. Hemen- 
way. All the results obtained were not conclusive, 
and it is impossible to give definite details relative to 
future work. Some of these results, however, are in- 
teresting, and are given herewith. Other tests should 
be made. 
After several preliminary experiments with some 
of the more delicate plants in a wooden box, two 
rooms, known as the stove and cactus, were fumigated 
at the same time, the connecting doors between them 
having been opened. Many of the cacti were infested 
with the common cactus scale, Diaspzs cactz, In the 
stove-room, all through the twining vines, were white 
waxy threads protecting the eggs and young mealy 
bugs. 
The cactus-room contained 7,076 cubic feet of air 
space and the stove-room 7,357 cubic feet. Forty 
ounces of potassium cyanide were used in each room, 
and they were kept closed for thirty minutes. The 
ventilators, which had been previously prepared, were 
then opened from the outside. The temperature of 
the house was about 60° F. The conditions of the 
weather were perfect for such a test, as it was rain- 
ing, the water filling all the cracks in the house, and 
thus preventing the escape of the gas. It was also 
warm outside, so the house was not cooled too low 
while the ventilators were open. It was perfectly 
dark. The ventilators were left open for about an 
hour, and closed for the night. 
The rcom contained many different kinds of cacti, 
begonias in variety, passifloras, allamandas, bananas 
