and by a succession of so many eminent men, every thing must
have been disclosed. Those who hold this opinion cannot be aware
that every discovery in science opens a new field of inquiry, and
that this is especially true of anatomy. No part of knowledge
stands so much connected with the other departments, and is so
universally dependent on discoveries in other sciences, as anatomy;
if we understand by that term the knowledge of the functions as
well as the structure of animal bodies.
I have regretted the influence of this opinion on our students,
because it takes from them that animation and pleasure which
belong to their time of life, and their peculiar studies, which, if
followed as they ought to be, afford an ever new hope and prospect
of discovery.
Nor ought the study of animal structure to be limited to that
only which appears useful; but, on the contrary, extended in a
liberal manner to all the ramifications which promise to improve
our general knowledge. We never know to what useful conclusion
the inquiry may lead, while it is sure to gratify us, to give rise to
admiration, and a sort of involuntary praise. At one time I thought
an apology was necessary for paying attention td expression, a subject
of mere amusement, when I might have been more usefully
employed; and now, if I shall have any reputation as a discoverer,
1 shall owe it principally to the views which this neglected subject
has suggested to me. Here I first learned to look upon the fabric
of the human body as a combination of parts which differed
essentially from things of human invention—that while the latter
were pieces fitted and contrived to produce some ultimate effect,
the former was cast with such perfection that each part performed
many functions. I saw in the face so many different offices performed,
that I began to inquire by what peculiarities of structure
this was attained, and being led to examine other organs in the
same manner, I laid the ground of my observations on the nervous
system.
A very remarkable error has been propagated, and as long as
it continued there could be little known of the machinery of expression
; nothing certainly, unless through our experience of the
sympathies planted in our nature. These sympathies, when followed
after the manner of philosophical inquiries, or pursued as
matters of taste, led to nothing, or at most to some unsubstantial
theory. However excellent the works may be which set forth
these theories, however to be valued for the beauties of composition,
for just sentiment and classical illustration, and all the graces of a
cultivated understanding, they leave us as to knowledge where
we were.
The error to which I have alluded is a substantial one, being
no less than a mistake as to the organs on which expression depends.
There is a system of nerves extended over the frame called
sympathetic, because they were universally believed to be the
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