180 DISCUSSION OF THE DESICCATION QUESTION. 



Of the importance of a covering of vegetation, either grassy or arboreal, 

 in protecting the soil from being washed away by violent rains, especially 

 and chiefly on steep mountain slopes, nothing need here be said, for the sub- 

 ject is well understood and extensively acted on in practice. But forests as 

 regulators of the flow of the excess of precipitation over any given surface, 

 and forests as causes of that precipitation, are two very different matters. 



A few words may here be added in reference to a point already suggested,* 

 namely, an assumed antagonism between man and nature, in consequence 

 of which, all nations, after having reached an advanced stage of development, 

 must sink into decay, a certain destructiveness, or hostile' influence, inherent 

 in the race, gradually rendering the earth unfit for habitation, and thus 

 bringing about the downfall of that prosperity to the permanent continu- 

 ance of which the physical conditions had become unsuited. 



Precisely in what this hostile influence consists it is not so easy to make 

 out. Perhaps its nature may be inferred, to some extent, from the follow- 

 ing quotations from a popular work which is largely devoted to an elucida- 

 tion of the conflict between man and nature : t " Man has too long forgotten 

 that the earth was given to him for usufruct alone, not for consiuuption, still 

 less for profligate waste. Nnture has provided against the absolute destruction 

 of any of her elementary matter, the raw material of her works; the thun- 

 derbolt and the tornado, the most convulsive throes of even the volcano and 

 the earthquake, being only phenomena of decomposition and recomposition. 

 But she has left it within the power of man irreparably to derange the com- 

 binations of inorganic matter and of organic life, which through the night 

 of seons she has been proportioning and balancing, to prepare the earth for 

 his habitation, when in the fulness of time his Creator should call him forth 



to enter into its possession But man is everywhere a disturbing 



agent. Wherever he plants his foot, the harmonies of nature are turned to 

 discords. The proportions and accommodations which insured the stability 

 of existing arrangements are overthrown. Indigenous vegetable and animal 

 species are extirpated and supplanted b_y others of foreign origin, sponta- 

 neous production is forbidden or restricted, and the face of the earth is either 

 laid bare or covered with a new and reluctant growth of vegetable forms, 

 and with alien tribes of animal life. These intentional changes and substi- 



* See ante, p. 164. 



t Tlie Earth as Modified by Human Action. By George P. Marsh. A New and Revised Edition. New 

 York, 1877. 



