BROWN EAT. 309 



organization and habits, or, on the other, to zoological 

 classification. There are, it is true, certain groups which 

 are strictly confined within the boundaries of a particular 

 tract of country ; there are some, the habitations of which 

 are evidently regulated by climate, by soil, or by the 

 necessity of a particular kind of food ; whilst others 

 appear to be located with very little regard to any ob- 

 vious object. Some individual species, again, are found 

 but in one small corner of the globe, where they exist, 

 perhaps, in inconsiderable numbers ; whilst others, capable 

 of procuring their nourishment from the products of every 

 region, and readily transplanted by means of the com- 

 mercial intercourse of various nations, become naturalized 

 in every new colony to which they have been accidentally 

 transported, and at length identified with the original 

 natives of their adopted country. Of those which fall 

 within the scope of the latter observation, there are none 

 to which it applies with more force than to the common 

 Brown Rat, which is now so generally distributed wher- 

 ever man has planted his foot, that its original country 

 can no longer be ascertained, although there is reason to 

 believe that it comes from a warmer climate than our 

 own. It was doubtless brought hither by means of 

 merchant vessels from some southern or south-eastern 

 couAtry — Pennant imagines from the East Indies. It 

 certainly was known in Asia long before we have any 

 account of its existence in any part of Europe ; and its 

 transit from the Asiatic borders into European Russia 

 was well ascertained. In Paris it made its appearance 

 about the middle of the eighteenth century, and in Eng- 

 land not very many years earlier. It is by a strange 

 mistake called by many the Norway Rat, as if it were 

 aboriginal in that country ; whereas in fact, at the time 

 when the name was first applied to it, it was not known 



