that of the other classes; and there is a peculiar circumstance attending
this causation, which is, that it is entirely suspended during sleep;
whilst the other classes of motion, which are more immediately necessary to
life, as those caused by internal stimuli, for instance the pulsations of
the heart and arteries, or those catenated with pleasurable sensation, as
the powers of digestion, continue to strengthen their habits without
interruption. Thus though man in his sleeping state is a much less perfect
animal, than in his waking hours; and though he consumes more than one
third of his life in this his irrational situation; yet is the wisdom of
the Author of nature manifest even in this seeming imperfection of his
work!

The truth of this assertion with respect to the large muscles of the body,
which are concerned in locomotion, is evident; as no one in perfect sanity
walks about in his sleep, or performs any domestic offices: and in respect
to the mind, we never exercise our reason or recollection in dreams; we may
sometimes seem distracted between contending passions, but we never compare
their objects, or deliberate about the acquisition of those objects, if our
sleep is perfect. And though many synchronous tribes or successive trains
of ideas may represent the houses or walks, which have real existence, yet
are they here introduced by their connection with our sensations, and are
in truth ideas of imagination, not of recollection.

2. For our sensations of pleasure and pain are experienced with great
vivacity in our dreams; and hence all that motley group of ideas, which are
caused by them, called the ideas of imagination, with their various
associated trains, are in a very vivid manner acted over in the sensorium;
and these sometimes call into action the larger muscles, which have been
much associated with them; as appears from the muttering sentences, which
some people utter in their dreams, and from the obscure barking of sleeping