y share the good
or evil which happens to either of them. The mind cannot put forth its
powers when the body is tired with inordinate exercise and too close
application to study destroys the body by dissipating the animal spirits
which are necessary to recruit it.[2]

The knowledge of the influence of the passions of the mind over the
bodily functions, is of ancient date. Plato, in his "_Timaeus_,"
states it as his firm conviction, that the spirit exerted a marked
influence in producing disease. This opinion was afterwards revived by
Helmont, Hesper Doloeus, and Stahl; the latter plainly says, that the
rational soul presides over and directs the animal functions. In this
doctrine he was followed by Nichols, in his "_Anima Medica_."
According to the doctrines of Stahl, the disorders of the body proceed
principally from the mind; and, according as it is variously affected,
it produces different effects (diseases.) Hence, when the mind, which
animates the most robust and best organized body, is violently agitated
by fright, rage, grief, vehement desire, or any other passion, whether
sudden, or attended by long and painful sensations, the body manifestly
suffers, and a variety of diseases, as apoplexy, palsy, madness, fever,
and hysterics, may be the consequence. If this be true, an attention to
the regulations of the mind is of much more importance than physicians
seem disposed to admit. The poet of health justly says,

"'Tis the great art of life to manage well
The restless mind."

In the course of this vitally important and deeply-interesting subject
of inquiry, it is not my intention to enter into any metaphysical
discussion respecting the inscrutable and mysterious union existing
between matter and mind, or to endeavour to point out the manner in
which the body influences the mind, and the mind the body. Such subjects
we do not think to be legitimate objects of inquiry. The medical
philosopher is engaged in less obscure and less uncertain researches; he
does not attempt to solve the question regarding the intimate union
subsisting between the natural and intellectual portions of our nature,
but he wisely confines himself to an attentive examination of the
phenomena which result from that union. Man is compounded of a soul and
body, so closely united, not _identified,_ that they frequently
struggle and occasionally overpower each other. Sometimes the mind
ascends the throne and subdues, in a moment, the physica