GREENHOUSE AND COLD FRAME FUMIGATION 135 
cess, only a few treatments during the season being 
required. Leaf-eating larvee, slugs, millipedes, cut- 
worms, etc., when exposed are killed as well as plant- 
lice. Red spiders, however, are not entirely eradicated 
by the treatment. The foliage of single violets, like 
California and Princess of Wales, are sometimes slightly 
injured by the stronger dose of gas. A weaker dose, 
one-tenth of a gramme potassium cyanide per cubic 
foot, should be used when they are to be treated. 
Other plants.—Other plants on which the gas has 
been tried on a small scale indicate that it may prob- 
ably have quite a wide range of usefulness. It has 
been used on the following plants at the rate of one- 
tenth gramme of cyanide per cubic foot of space for 
twenty minutes without injury. Further experiment, 
however, is necessary before the treatment can be 
recommended for these: Alocasia macrorhiza variegata,; 
Anthurium crystallinum, Areca lutescens, Aralia filici- 
folia; Adiantum cuneatum, Adiantum ballit; Campy- 
lobotrys refulgens; Cissus discolor; Crotons (in variety ), 
Cichorium intybus,; Diffenbachia lenmannii; Ficus elas- 
tica, Fuchsias (in variety) ; Jacaranda mimosefolia ; 
Marantas (in variety); Mymphea candidissima, and 
odorata rosea; Pontederia crasstpes; Pandanus vettchiz; 
Phrynium variegatum,; Phyllotenium lindenti; Panax 
victorie, Stenanthium lindenit. 
Roses.—Perle des jardins, Mermet, and Bride. 
The young growth on roses is particularly sensitive, 
and has been more or less injured in all our experi- 
ments. 
Carnations.—Scott, Garfield, Meteor, and Mc- 
