s is only an additional reason why it should be begun
in a proper manner, and pursued with energy. The mode of procedure is
the chief object of difficulty; but the experience and success of
investigators in the other sciences, will be of great advantage in
directing us in this. In the sciences of anatomy and physiology, for
example, the investigations of the philosopher are designed to direct
the several operations of the physician, the surgeon, and the dentist;
in the same way as the investigations of the Educationist are intended
to direct the operations of the Teacher. Now the mode of procedure in
those sciences for such purposes is well known, and forms an excellent
example for us in the present case. The duty of the anatomist, or
physiologist, is simply to examine the operations of Nature in the
animal economy, and the plans which she adopts for accomplishing her
objects during health, and for throwing off impediments during disease.
In conducting his investigations, the enquirer begins by taking a
general view of the whole subject, and then separating and defining its
leading parts. Pulsation, respiration, digestion, and the various
secretions and excretions of the body, are defined, and their general
connection with each other correctly ascertained. These form his
starting points; and then, taking each in its turn, he sets himself to
discover the principles, or laws, which regulate its working in a
healthy state;--what it is that promotes the circulation or stagnation
of the blood, the bracing or relaxing of the nerves, the several
processes in digestion, and the various functions of the skin and
viscera. These are all first ascertained by observation and experience,
and then, if necessary, established by experiment.

These principles, having thus been established by science, are available
for direction in the arts. The physician acts under their guidance; and
his object is simply to regulate his treatment and advice in accordance
with them. In other words, _he endeavours to imitate Nature_, to remove
the obstructions which he finds interfering with her operations, or to
lend that aid which a knowledge of these principles points out as
necessary. The surgeon and the dentist follow the same course, but more
directly. In healing a wound, for example, the surgeon has to ascertain
from science how Nature in similar cases proceeds when left to herself;
and all his cuttings, and lancings, and dressings, are nothing more