motions have been shewn in a former part of this work to depend on the
irritations of peculiar fluids, and as they have never been classed amongst
the instinctive actions of animals, are precluded from our present
disquisition.

But all those actions of men or animals, that are attended with
consciousness, and seem neither to have been directed by their appetites,
taught by their experience, nor deduced from observation or tradition, have
been referred to the power of instinct. And this power has been explained
to be a _divine something_, a kind of inspiration; whilst the poor animal,
that possesses it, has been thought little better than _a machine_!

The _irksomeness_, that attends a continued attitude of the body, or the
_pains_, that we receive from heat, cold, hunger, or other injurious
circumstances, excite us to _general locomotion_: and our senses are so
formed and constituted by the hand of nature, that certain objects present
us with pleasure, others with pain, and we are induced to approach and
embrace these, to avoid and abhor those, as such sensations direct us.

Thus the palates of some animals are gratefully affected by the mastication
of fruits, others of grains, and others of flesh; and they are thence
instigated to attain, and to consume those materials; and are furnished
with powers of muscular motion, and of digestion proper for such purposes.

These _sensations_ and _desires_ constitute a part of our system, as our
_muscles_ and _bones_ constitute another part: and hence they may alike be
termed _natural_ or _connate_; but neither of them can properly be termed
_instinctive_: as the word instinct in its usual acceptation refers only to
the _actions_ of animals, as above explained: the origin of these _actions_
is the subject of our present enquiry.