296 MAN AND NATURE. 



sign of which Man cannot be the single object, even if 

 he be the final termination of the series. 



The modes through which Man exercises his power 

 over the animal and vegetable life of the earth we may 

 briefly denote as being either by culture and augmenta- 

 tion, or by extirpation, or by transference of species 

 from one region to another. Many examples of these 

 modes of action will at once be obvious. But there are 

 others not equally familiar, though very important to the 

 well-being of mankind ; and connected with that phe- 

 nomenon of high interest in the economy of the globe, 

 viz., the local apportionment of genera and species, 

 and even of certain types of life, to particular portions 

 of its surface. Without speaking of the many curious 

 and inexplicable cases of limitation of species to a 

 single spot, we may cite a few general facts in illustra- 

 tion, such as that of the Cactacea3 being peculiar to the 

 New World, the heaths to the Old ; that no rose has 

 been found in the Southern hemisphere, no oak tree or 

 wild apple in the vast regions of Siberia from the Tobol 

 to the Amour ; that the salmon, existing around the globe 

 in certain latitudes of our hemisphere, is nowhere found 

 in the Southern, &c. This singular distribution of the 

 forms of life (original we may call it, as far as Man's 

 existence is concerned) has furnished problems of 

 equal and similar interest to the zoologist and botanist, 

 with a further appeal to the geologist in seeking for 

 their solution. But long before speculation had been 

 directed to these local diversities or provinces of life 

 on the earth, practical changes were already in opera- 

 tion, in the transference from one region to another, 



