vens.

close to us: the change applies immediately to our fenfations: of all the phænomena of nature, it is the most familiar to our experience: but, in its caufe, it belongs to the great motions which are paffing in the heaWhilst the earth glides round her axle, fhe minifters to the alternate neceffities of the animals dwelling upon her surface, at the same time that the obeys the influence of thofe attractions which regulate the order of many thousand worlds. The relation therefore of fleep to night, is the relation of the inhabitants of the earth to the rotation of their globe; probably it is more: it is a relation to the system, of which that globe is a part; and, ftill further, to the congregation of systems, of which theirs is only one. If this account be true, it connects the meaneft individual with the universe itself; a chicken roofting upon its perch, with the spheres revolving in the firmament.

But if any one object to our representation, that the fucceffion of day and night, or the rotation of the earth upon which it depends, is not refolvible into central attraction, we will refer him to that which certainly is,—to the change of the feafons. Now the conftitu

tion of animals fufceptible of

torpor,

bears a

relation to winter, fimilar to that which fleep bears to night. Against not only the cold, but the want of food, which the approach of winter induces, the preferver of the world has provided, in many animals by migration, in many others by torpor. As one example out of a thousand, the bat, if it did not fleep through the winter, must have starved, as the moths and flying infects, upon which it feeds, disappear. But the tranfition from fummer to winter carries us into the very midst of physical astronomy, that is to fay, into the midst of those laws which govern the folar system at least, and probably all the heavenly bodies.

CHAPTER XVIII.

INSTINCTS.

THE order may not be very obvious, by which I place inftincts next to relations. But I confider them as a species of relation. They contribute, along with the animal organization, to a joint effect, in which view they are related to that organization. In many cafes they refer from one animal to another animal; and, when this is the cafe, become strictly relations in a second point of view.

An INSTINCT is a propenfity, prior to experience, and independent of instruction. We contend, that it is by inftinct that the sexes of animals feek each other; that animals cherish their offspring; that the young quadruped is directed to the teat of its dam; that birds build their nefts, and brood with fo much patience upon their eggs; that infects, which do not fit upon their eggs, depofit them in those particular fituations, in which the young, when hatched, find their appropriate food; that it is instinct, which carries the

falmon,

falmon, and fome other fish, out of the fea into rivers, for the purpose of shedding their fpawn in fresh water.

We may fele& out of this catalogue the incubation of eggs. I entertain no doubt, but that a couple of sparrows hatched in an oven, and kept separate from the reft of their species, would proceed as other fparrows do, in every office which related to the production and preservation of their brood. Afsuming this fact, the thing is inexplicable upon any other hypothesis, than that of an instinct, impreffed upon the conftitution of the animal. For, first, what should induce the female bird to prepare a neft before she lays her eggs? It is in vain to suppose her to be poffeffed of the faculty of reasoning; for no reasoning will reach the cafe. The fullness or diftenfion which she might feel in a particular part of her body, from the growth and folidity of the egg within her, could not poffibly inform her, that she was about to produce fomething, which, when produced, was to be preferved and taken care of. Prior to experience, there was nothing to lead to this inference, or to this fufpicion. The analogy was all against it; × 3

for,

for, in every other inftance, what iffued from the body was caft out and rejected.

But, fecondly, let us fuppofe the egg to be produced into day: How should birds know that their eggs contain their young? There is nothing either in the afpect, or in the internal composition of an egg, which could lead even the most daring imagination to a conjecture, that it was hereafter to turn out, from under its fhell, a living perfect bird. The form of the egg bears not the rudiments of a refemblance to that of the bird. Infpecting its contents, we find ftill less reason, if poffible, to look for the refult which actually takes place. If we should go fo far, as, from the appearance of order and diftinction in the difpofition of the liquid fubftances which we noticed in the egg, to guess that it might be defigned for the abode and nutriment of an animal, (which would be a very bold hypothefis,) we fhould expect a tadpole dabbling in the flime, much rather than a dry, winged, feathered creature; a compound of parts and properties impoffible to be used in a ftate of confinement in the egg, and bearing no conceivable relation, either in quality or material, to any thing obferved in

it.