19G ON THE GEOGRAPHICAL 



of vegetables from one country to another ; and, by cul- 

 tivation, be has so changed the face of nature which sur- 

 rounds him, that the surface of the earth has, in some 

 measure, lost its primeval features, and vegetation, at 

 least, has experienced great modifications. Most animals 

 have tlu' means of spreading themselves on the surface of 

 the globe. The element which saw their birth, offers no 

 limits to marine animals. Certain mammals extend, con- 

 stantly, the sphere of their habitation, and spread them- 

 selves by degrees over many parts of the Avorld. Other 

 species accompany man in his peregrinations, even beyond 

 seas, dispersing themselves in diverse regions, either when 

 transplanted by man himself, or wlicn, recovering their 

 liberty, they form, as it were, colonies far from their 

 mother country, where it sometimes happens that tlieir 

 race is totally destroyed, or that all the individuals have 

 ])assed to the domestic state. Birds enjoy more than other 

 animals the faculty of moving from one j^hice to another ; 

 the element in which they move nowhere presenting obsta- 

 cles to them, a large part of the inhabitants of the air lead 

 a real nonuide life, and often establish themselves in places 

 where they were never seen before ; a great number dis- 

 ])erse themselves, in their periodic migrations, into coun- 

 tries the most distant, and become true cosmopolites ; tlie 

 same species inhabiting, at the same time, all parts of the 

 earth. It is far otherwise with Reptiles. None of the 

 circumstances we have mentioned can be rigorously ap- 

 plied to these animals. Deprived, for the most part, of 

 the means of performing distant journies, they are, in 

 some measure, attached to the soil which gave them birth ; 

 and we do not recognise in them any instinct to flee the 

 natal soil, when certain circumstances would seem to de- 

 mand it. The cold which deprives them of the means of 

 subsistence, causes them at the same time to fall into a 

 profound lethargy ; and Nature, in this simple manner, 

 watches over their preservation during the winter. Man 

 entertains an aversion for these animals, some of w^hich 

 are noxious, it is true, but many of them are innocuous, 

 and even useful ; he repels them all, and seeks not to 

 tame them ; still less is he inclined to transplant them, 



