NATURAL HISTORY OF SELBORNE. 261 
be eee le Vol. 
TO THE SAME. 
THEY who write on natural history cannot too frequently advert 
to instinct, that wonderful limited faculty, which, in some instances, 
rises the brute creation as it were, above reason, and in others 
leaves them so far below it. Philosophers have defined instinct to 
be that secret influence by which every species is impelled naturally 
to pursue, at all times, the same way or track, without any teaching 
or example; 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 instinct 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 to itself, so that a school-boy would at once 
pronounce on the sort of nest before him. This is the case among 
fields and woods, and wilds; but, in the villages round London, 
where mosses and gossamer, and cotton from vegetables, are hardly 
to be found, the nest of the chaffinch has not that elegant finished 
appearance, nor is it so beautifully studded with lichens, as in a 
more rural district ; and the wren is obliged to construct its house 
with straws and dry grasses, which do not give it that rotundity 
and compactness so remarkable in the edifices of that little archi- 
tect. Again, the regular nest of the house-martin is hemispheric; 
but where a rafter, or a joist, or a cornice, may happen to stand in 
the way, the nest is so contrived as to conform to the obstruction, 
and becomes flat, or compressed. 
In the following instances instinct is perfectly uniform and con- 
sistent. There are three creatures, the squirrel, the field-mouse, 
and the bird called the nut-hatch (sétta Europea), which live much 
on hazel-nut ; and yet they open them each in a different way. 
The first, after rasping off the small end, splits the shell in two 
with his long fore-teeth, as a man does with his knife ; the second 
nibbles a hole with his teeth, so regular as if drilled with a wimble, 
