300 MAN AND NATURE. 



and by the place they occupy in the classification of 

 the zoologist. But this place is so defined as ever to 

 render them objects of deep interest, and of curious 

 though not pleasant speculation to our reason. 



The most remarkable examples of numerical in- 

 crease in species occur in those new countries to which 

 Man has transported the animals valuable to him for 

 domestic uses. In the vast regions west of the 

 Alleghanies, in the Pampas of South America, and in 

 the new world of Australia, the multiplication of these 

 animals of the horse, cattle, sheep, and swine has 

 been on a scale more than commensurate with that of 

 human population. Bevelling in their wide and un- 

 fenced domains, severally more spacious than European 

 kingdoms, and breeding there with unwonted rapidity, 

 some of these animals have even relapsed into the wild 

 state, and become again the prey of the hunter. 

 Everywhere they not merely aid the growth of popu- 

 lation on the spot, but yield large material for export 

 to the very countries from which their own races were 

 derived. 



And this leads us to speak of that power, which 

 Man has so extensively used, of making one region of 

 the globe minister to another, not solely through the 

 products of animal and vegetable life, but by local ex- 

 change of the animals and plants producing them. 

 This forms an extraordinary chapter in the natural 

 history of the earth, and one that deserves to be more 

 carefully read than it is. We must note, however, in 

 the outset, that this transport and exchange is not due 

 to Man alone, but, in the case of plants more espe- 



