They who write on natural history cannot too frequently advert to
instinct, that wonderful limited faculty, which in some instances raises
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 compelled 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 convenience.
It has been remarked that every species of bird has a mode of
nidification peculiar to itself, so that a schoolboy 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 consistent.
There are three creatures, the squirrel, the field-mouse, and the bird
called the nut-hatch (_sitta Europaea_), which live much on hazelnut; 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, and yet so small that one could 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 gatepost 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:--
"Praehabebat porro vocibus humanis, instrumentisque harmonicis musicam
illam avium: non quod alia quoque non delectaretur: sed quod ex musica
humana relinqueretur in animo continens quaedam, attentionemque et
somnum conturbans agitatio; dum ascensus, exscensus, tenores, ac
mutationes illae sonorum, et consonantiarum euntque, redeuntque per
phantasiam:--cum nihil tale relinqui possit ex modulationibus avium
quae, quod non sunt perinde a nobis imitabiles, non possunt perinde
internam facultatem commovere."--_Gassendus in Vita Peireskii_.
This curious quotation strikes me much by so well representing my own
case, and by describing what I have so often felt, but never could so
well express. When I hear fine music I am haunted with passages
therefrom night and day; and especially at first waking, which, by their
importunity, give me more uneasiness than pleasure; elegant lessons still
tease my imagination, and recur irresistibly to my recollection at
seasons, and even when I am desirous of thinking of more serious matters.