FINAL CAUSES. 15 



stances are compatible with vegetable existence, 

 we there find plants arise. It is well known 

 that, in all places where vegetation has been 

 established, the germs are so intermingled with 

 the soil, that whenever the earth is turned up, 

 even from considerable depths, and exposed to 

 the air, plants are soon observed to spring, as if 

 they had been recently sown, in consequence of 

 the germination of seeds which had remained 

 latent and inactive during the lapse of perhaps 

 many centuries. Islands formed by coral reefs, 

 which have risen above the level of the sea, 

 become, in a short time, covered with verdure. 

 From the materials of the most sterile rock, and 

 even from the yet recent cinders and lava of the 

 volcano, Nature prepares the way for vegetable 

 existence. The slightest crevice or inequality is 

 sufficient to arrest the invisible germs that are 

 always floating in the air, and affords the means 

 of sustenance to diminutive races of lichens and 

 mosses. These soon overspread the surface, and 

 are followed, in the course of a few years, by 

 successive tribes of plants of gradually increasing- 

 size and strength ; till at length the island, or 

 other favoured spot, is converted into a natural 

 and luxuriant garden, of which the productions, 

 rising from grasses to shrubs and trees, present 

 all the varieties of the fertile meadow, the tangled 

 thicket, and the widely spreading forest. Even 

 in the desert plains of the torrid zone, the eye of 



