eir nourishment.
These are devoured by animals, which in their turn die, and are
decompounded; thus, in the living world, as well as in the inanimate,
every thing is subject to change, and to be renewed perpetually.

"Look nature through, 'tis revolution all,
All change, no death; day follows night; and night,
The dying day; stars rise, and set, and rise;
Earth takes th' example; see the summer gay,
With her green chaplet, and ambrosial flowers,
Droops into pallid autumn; winter gray,
Horrid with frost, and turbulent with storm,
Blows autumn and his golden fruits away,
Then melts into the spring; soft spring with breath
Favonian, from warm chambers of the south
Recals the first. All to reflourish, fades;
As in a wheel, all sinks to reascend."

The subject on which we are entering is of the utmost importance;
for, by pointing out the manner in which life is supported and
modified by the action of external powers, it discovers to us the
true and only means of promoting health and longevity; for the action
of these powers is generally within our own direction; and if the
action of heat, food, air, and exercise, were properly regulated, we
should have little to fear from the attacks of diseases.

When we examine the human body, the most curious and unaccountable
circumstance that we observe, is its life, or its power of motion,
sensation, and thought: for though the structure of the different
parts which we have examined must excite our admiration and wonder,
each part being admirably fitted for the performance of its different
functions, yet without the breath of life, all these beautiful
contrivances would have been useless. We have seen that the structure
of the eye indicates in its contriver, the most consummate skill in
optics; and of the ear the most perfect knowledge of sounds; yet if
sensibility had not being given to the nerves which administer to
these organs, the pulses of the air might have been communicated to
the fluid in the labyrinth, and the rays of light might have formed
images in the retina, without our being, in the smallest degree,
conscious of their existence.

Though our efforts to discover the nature of life have hitherto been,
and perhaps always will be, unsuccessful, yet we can, by a careful
induction, or observation of facts, discover the laws by which it is
governed, with respect to the action of external objects. This is
what I shall now attempt to do