PREFACE TO THE FIEST EDITION. 



The object of the present volume is : to indicate the character 

 and, approximately, the extent of the changes produced by hu- 

 man action in the physical conditions of the globe we inhabit ; 

 to point out the dangers of imprudence and the necessity of cau- 

 tion in all operations which, on a large scale, interfere with the 

 spontaneous arrangements of the organic or the inorganic world ; 

 to suggest the possibility and the importance of the restoration of 

 disturbed harmonies and the material improvement of waste and 

 exhausted regions ; and, incidentally, to illustrate the doctrine 

 that man is, in both Mnd and degree, a power of a higher order 

 tiian any of the other forms of animated life, which, like him, 

 are nourished at the table of bounteous nature. 



In the rudest stages of life man depends upon spontaneous 

 animal and vegetable growth for food and clothing, and his con- 

 sumption of such products consequently diminishes the numerical 

 abundance of the species which serve his uses. At more ad- 

 vanced periods, he protects and propagates certain esculent vege- 

 tables and certain fowls and quadrupeds, and, at the same time, 

 he wars upon rival organisms which prey upon these objects of 

 his care or obstruct the increase of their numbers. Hence the 

 action of man upon the organic world tends to derange its orig- 

 iaal balances, and while it reduces the numbers of some species, 

 or even extirpates them altogether, it multiplies other forms of 

 animal and vegetable life. 



The extension of agricultural and pastoral industry involves 



(Tii) 



