NATURAL HISTORY OF SELBORNE. 
185 
LETTEE LVI. 
TO THE SAME. 
They who write on natural history cannot too frequently advert 
to instinct, that wonderful limited faculty, w^hich, in some instances, 
rises the brute creation as it were, above reason, and in others leaves 
them so far below it. Philosophers have denied 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 circumstances of place and con- 
venience. 
It has been remarked that every species of bird has a mode of nidifi- 
cation 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 architect. 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 {sitta Europcea), which live much on hazel- 
nut ; and yet they open them each in a different w^ay. 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, and yet so small 
that one would wonder how the kernel can be extracted through it ; 
while the last picks an irregular ragged hole with its bill : but as this 
artist has no paws to hold the nut firm while he pierces it, like an 
adroit workman, he fixes it, as it were, in a vice, in some cleft of a tree, 
or in some crevice ; when, standing over it, he perforates the stubborn 
shell. We have often placed nuts in the chink of a gate-post where 
nut-hatches have been known to haunt, and have always found that 
those birds have readily penetrated them. While at work they make a 
rapping noise that may be heard at a considerable distance. 
You that understand both the theory and practical part of music 
may best inform us why harmony or melody should so strangely assist 
some men, as it were by recollection, for days after the concert is over. 
What I mean the following passage will most readily explain : — 
