their revolution round the great source of heat and light.

'-----All combin'd
'and ruled unerring, by that single power
'which draws the stone projected, to the ground.'

In the animated part of the creation, we observe those beautiful
phenomena which are exhibited by an almost infinite variety of
individuals, all depending upon one simple law, the action of the
exciting powers on the excitability.

I cannot express my admiration of the wisdom of the creator better
than in the words of Thomson.

'O unprofuse magnificence divine!
'O wisdom truly perfect! thus to call
'from a few causes, such a scheme of things;
'effects so various, beautiful, and great.'

Life then, or those functions which we call living, are the effects
of certain exciting powers, acting on the excitability, or property
distinguishing living from dead matter. When those effects, namely,
the functions, flow easily, pleasantly, and completely, from the
action of the exciting powers, they indicate that state which we
call Health.

I have detained you a long time on this subject, but it is of
importance to make you acquainted with these laws; for it is from a
knowledge of them, that the rules for preserving health must be
deduced; and having rendered them, as I hope, intelligible to you, I