THE HOUSELEEK TRIBE. 107 



they, in common with all other plants, but in a higher 

 degree, possess of abstracting from the atmosphere its 

 impure air, or carbonic acid, which they convert from 

 a gaseous into a solid state, by separating the charcoal 

 or solidifiable portion, and liberating the vital air or 

 oxygen that was combined with it. By this wondrous 

 process, living plants become the great purifiers of the 

 air we breathe, and it appears quite certain, that if it 

 were not for them the earth would soon become so pes- 

 tiferous as to be uninhabitable. 



All nature is in a continual state of decay and reno- 

 vation. The perishing remains of animals and plants 

 exhale putrid effluvia, which mix with the atmosphere 

 and reAder it impure ; the incessant action of respira- 

 tion through the whole animal world, increases the im- 

 purity by abstracting the vital air or oxygen, and sub- 

 stituting foul air or carbonic acid. This combined 

 action has been going on from the beginning of the 

 present order of created things, and yet it does not 

 appear that the air we breathe is less suited to our 

 constitutions now than it was in the beginning. This 

 is owing to the agency of plants, which, existing 

 wherever animals or man can exist, are perpetually at 

 hand to catch up and consume the impure particles of 

 the atmosphere as fast as they are generated, and by 

 fixing the carbonaceous part in their owti systems, and 

 again liberating the vital air or oxygen, with which the 

 former was in combination, they restore to the air all 

 the purity it had lost. 



Here, then, you have another of those admirable 

 proofs of wisdom and design that meet the philosophical 



