TO INANIMATE NATURE. 
169 
never observed but to admire, the satisfaction, no less than 
the regularity, with which the greatest part of the irration¬ 
al world yield to this soft necessity, this grateful vicissi¬ 
tude: how comfortably the birds of the air, for example, 
address themselves to the repose of the evening; with what 
alertness they resume the activity of the day! 
Nor does it disturb our argument to confess, that certain 
species of animals are in motion during the night, and at 
rest in the day. With respect even to them, it is still true, 
that there is a change of condition in the animal, and an 
external change corresponding with it. There is still the 
relation, though inverted. The fact is, that the repose of 
other animals sets these at liberty, and invites them to their 
food or their sport. 
If the relation of sleep to night, and, in some instances, 
its converse, be real, we cannot reflect without amazement 
upon the extent to which it carries us. Day and night are 
things close to us; the change applies immediately to our 
sensations; of all the phenomena of nature, it is the most 
obvious and the most familiar to our experience; but in its 
cause, it belongs to the great motions which are passing 
in the heavens. Whilst the earth glides round her axle, 
she ministers to the alternate necessities of the animals 
dwelling upon her surface, at the same time that she obeys 
the influence of those attractions which regulate the order 
of many thousand worlds. The relation therefore of sleep 
to night, is the relation of the inhabitants of the earth to 
the rotation of their globe; probably it is more; it is a re¬ 
lation to the system, of which that globe is a part; and still 
farther, to the congregation of systems, of which theirs is 
only one. If this account be true, it connects the meanest 
individual with the universe itself: a chicken roosting upon 
its perch, with the spheres revolving in the firmament. 
VIII. But if any one object to our representation, that 
the succession of day and night, or the rotation of the earth 
upon which it depends, is not resolvable into central at¬ 
traction, we will refer him to that which certainly is,—to 
he change of the seasons. Now the constitution of ani¬ 
mals susceptible of torpor, bears a relation to winter, simi¬ 
lar to that which sleep bears to night. Against not only the 
cold, but the want of food which the approach of winter 
induces, the Preserver 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 sleep 
through the winter, must have starved, as the moths and 
flying insects, upon which it feeds, disappear. But the 
P 
