42 HUMAIS^ AND BRUTE ACTIOT^ COMPAEED. 



that corresponds to this ? "We have no reason to beheve that, in 

 that portion of the American continent which, though peopled 

 by many tribes of quadruped and fowl, remained uninhabited by 

 man or only thinly occupied by purely savage tribes, any sensible 

 geographical change had occurred within twenty centuries before 

 the epoch of discovery and colonization, while, during the same 

 period, man had changed millions of square miles, in the fairest 

 and most fertile regions of the Old World, into the barrenest 

 deserts. 



[The ravages committed by man subvert the relations and de- 

 stroy the balance which nature had estabhshed between her or- 

 ganized and her inorganic creations, and she avenges herself upon 

 the intruder, by letting loose upon her defaced provinces de- 

 structive energies hitherto kept in check by organic forces des- 

 tined to be his best auxiliaries, but which he has unwisely dis- 

 persed and driven from the field of action. When the forest is 

 gone, the great reservoir of moisture stored up in its vegetable 

 mould is evaporated, and returns only in deluges of rain to wash 

 away the parched dust into which that mould has been converted. 

 The well-wooded and humid hills are turned to ridges of dry 

 rock, which encumber the low grounds and choke the water- 

 com'ses with their debris, and — except in countries favored with 

 an equable distribution of rain through the seasons, and a moder- 

 ate and regular inchnation of surface — the whole earth, unless 

 rescued by human art from the physical degradation to which it 

 tends, becomes an assemblage of bald mountains, of barren, turf- 

 less hills, and of swampy and malarious plains. There are parts 

 of Asia Minor, of Northern Africa, of Greece, and even of Al- 

 pine Europe, where the operation of causes set in action by man 

 has brought the face of the earth to a desolation almost as com- 

 plete as that of the moon ; and though, within that brief space of 

 Itime which we we call " the historical period," they are known to 

 have been covered with luxuriant woods, verdant pastures, and 

 fertile meadows, they are now too far deteriorated to be reclaim- 

 vegetable and even of animal species. But when the bird drops the seed of a 

 fruit it has swallowed, and when the sheep transports in its fleece the seed- 

 vessel of a burdock from the plain to the mountain, its action is purely me- 

 chanical and unconscious, and does not differ from that of the wind in pro- 

 ducing the same effect. 



