48 WINDOW AND PARLOR GARDENING 
In many dwelling-houses the atmosphere is excessively dry, 
and where this is the case a good many useful plants cannot be 
grown. Many kinds of insects are liable to attack plants ina 
dry atmosphere. Much can be done to overcome this trouble 
by spraying the foliage often, or by growing plants that require 
a great deal of moisture in terrariums or double windows. 
Many Ferns, Orchids, and tropical foliage-plants require an at- 
mosphere laden with moisture. Cacti, many kinds of bulbous 
plants, Palms, and Bromeliads, as also many florist-flowers, do 
well in a dry room, but all except Cacti need occasional wash- 
ings and sprayings. 
A room in which the atmosphere is kept sweet and buoyant 
by means of heating and ventilation, can produce as good 
flowers as the best greenhouse. 
