110 



NATURAL IIISTORy 



LETTER LVL 



TO THE SAME. 



They who write on natural history can- 

 . not too frequent advert to instinct, that 

 wonderful limited faculty, which, in some 

 instances, raises the brute creation as it 

 were above reason, and m others leaves 

 them so far below it. Philosophers have 

 defined instinct to be that secret influence 

 by which every species is impelled natu- 

 rally to pursue, at all times, the same 

 way or track, without any teaching or ex- 

 ample ; whereas reason, without instruction, 

 . would often vary and do that by many 

 methods which instinct effects by one alone. 

 Now this maxim must be taken in a qualified 

 sense ; for there are instances in which in- 

 stinct does vary and conform to the circum- 

 stances of place and convenience. 



It has been remarked that every species 

 of bird has a mode of nidification peculiar 



