gO MANAGEMENT OF THE FORCING-HOUSE. 
Bisulphide of carbon.—This material has recently as- 
sumed a prominent position as an effective insecticide. It 
is a clear, transparent liquid, which evaporates rapidly, 
even at a low temperature. These fumes are fatal to in- 
sect as well as animal life, and may be used to a limited 
extent in the greenhouse. The vapor is of greatest value 
in destroying a small mite ( 7etranychus bimaculatus), 
that closely resembles the red spider. This mite is not 
as easily overcome by water as the red spider is, and in 
certain cases it may be advisable to resort to the bisul- 
phide of carbon treatment. This treatment is adapted to 
plants which are growing in pots, or to low-growing 
plants in beds. Whole houses could scarcely be treated 
in this manner, as the vapor is heavy, and an uneven dis- 
tribution would probably result. But for small, con- 
fined spaces, as bell-jars, tubs, or barrels, the remedy can 
be used with success. I have had no difficulty in de- 
stroying mites and red spider by the use of 60 minims 
or drops of the liquid to a space containing about 7 cubic 
feet. The liquid was poured on cotton batting, which was 
spread over a small rose from a watering can, the stem 
of the funnel being set in the soil. The plants remained 
covered with enamel cloth nearly two hours, which suf- 
ficed to kill all the insects, and did not injure the violets, 
these being the plants treated. 
Hydrocyanic gas.—The success which has followed the 
use of hydrocyanic gas in the treatment of scale insects 
infesting the orange groves of California has suggested 
the idea of its possible value in destroying greenhouse 
pests. The common method of making the gas is as fol- 
lows: One fluidounce of sulphuric acid is slowly added 
to 3 ounces of water. To this diluted acid there is then 
added 1 ounce of 60 per cent cyanide of potassium (very 
poisonous). Effervescence immediately takes place, and 
the gas is freely given off. The quantities here given are 
sufficient for a space containing 150 cubic feet, the plants 
being exposed to the gas for one hour. When trees are 
