EFPECT OP PLANT AND ANIMAL LIFE 387 



mansions, and * quarters' are undermined, and wliole villages, 

 once the home of wealth and luxury, are being swept away at 

 the rate of acres for each year. ' ' 



''The ravages committed by man," writes Marsh,i '' subvert 

 the relations and destroy the balance which nature had estab- 

 lished between her organized and her inorganic creations, and 

 she avenges herself upon the intruder by letting loose upon her 

 defaced provinces destructive energies hitherto kept in check 

 by organic forces destined to be his best auxiliaries, but which 

 he has unwisely dispersed 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 

 ai'e turned to ridges of dry rock, which encumbers the low 

 grounds and chokes the watercourses with its debris, and — 

 except in countries favored with an equable distribution of rain 

 through the seasons, and a moderate and regular inclination 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, turfless hills, and of swampy and 

 malarious plains. There are parts of Asia Minor, of northern 

 Africa, of Greece, and even of Alpine Europe, where the opera- 

 tion of causes set in action by man has brought the face of the 

 earth to a desolation almost as complete as that of the moon; 

 and though, within that brief space of time which 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 reclaimable by man, nor can 

 they become again fitted for human use, except through great 

 geological changes, or other mysterious influences or agencies 

 of which we have no present knowledge, and over which we 

 have no prospective control. The earth is fast becoming an 

 unfit home for its noblest inhabitant, and another era of equal 

 human crime and human improvidence, and of like duration 

 with that through which traces of that crime and that improvi- 

 dence extend, would reduce it to such a condition of impover- 

 ished productiveness, of shattered surface, of climatic excess, 

 as to threaten the depravation, barbarism, and perhaps even 

 extinction of the species." 



^The EaTth as modified by Human Action, a new edition of Man and 

 Nature, by Geo. P. Marsh, pp. 43, 44, 



