th. It
would likewise lay the foundation for the attainment of a more just,
accurate, and practical knowledge of our _intellectual_ and _moral
nature_. There is a _physiology_ of the _mind_ as well as of the _body_,
and both are so intimately united that neither can be well understood
without the study of the other. The physiology of man comprehends both.
Were even what is already known of this science and what might be easily
communicated made a part of general education, how many evils would be
avoided! how much light would be let in upon the understanding! and how
many aids would be afforded to the acquisition of a sound body and a
vigorous mind! prerequisites more important than are commonly supposed
to the attainment of wisdom and the practice of virtue.

Human physiology, says Dr. Combe, in his admirable treatise on that
subject, from which I have already quoted, is as important in its
practical consequences as it is attractive to rational curiosity. In its
widest sense, it comprehends an exposition of the functions of the
various organs of which the human frame is composed; of the mechanism by
which they are carried on; of their relations to each other, or the
means of improving their development and action; of the purposes to
which they ought severally to be directed, and of the manner in which
exercise ought to be conducted, so as to secure for the organ the best
health, and for the function the highest efficacy. A true system of
physiology comes thus to be the proper basis, not only of a sound
_physical_, but of a sound _moral_ and _intellectual_ education, and of
a rational hygiene; or, in other words, it is the basis of every thing
having for its object the physical and mental health and improvement of
man; for, so long as life lasts, the mental and moral powers with which
he is endowed manifest themselves through the medium of organization,
and no plan which he can devise for their cultivation, that is not in
harmony with the laws which regulate that organization, can possibly be
successful.

Let it not be said that knowledge of this description is superfluous to
the unprofessional reader; for society groans under the load of
suffering inflicted by causes susceptible of removal, but left in
operation in consequence of our unacquaintance with our own structure,
and of the relation of different parts of the system to each other and
to external objects. Every medical man must have felt and lamented the
ignor