THE FERN PARADISE. 
Through these tiny but multitudinous apertures 
plants breathe, inspiring the atmosphere which sur- 
rounds them, appropriating what they require for 
their sustenance and growth, and respiring what 
they do not need. The carbonic acid gas of the 
atmosphere is only absorbed by plants that they 
may be enabled to extract from it its carbon con- 
stituent. Having done this, the oxygen of the 
compound is set free, and returned again to the 
air which gave it, for the use and healthful enjoy- 
ment of animal life. 
How simple, then, and beautiful is this process, 
by which animals and plants minister so essen- 
tially to each other’s necessities ! And it neces- 
sarily follows that the proximity of plants is 
conducive to a purification of the atmosphere by 
the absorption of carbonic acid gas. If this ap- 
plies, as it does, in the open air, where forests, 
woods and other abundant vegetation play a large 
part in the healthfulness of a locality, it applies 
also to the confined atmosphere of a room. No 
doubt, the most active operation of the process 
by which plants absorb carbonic acid gas, retain 
the carbon of the compound, and give back to the 
206 
