rfulness or depression, comfort or
discomfort, hope or despair. These lines, whether temporary or
permanent, are made by the contractions of certain muscles passing from
one part of the skin to another or from the underlying bones to the
skin. These are known in our anatomical textbooks by the natural but
absurd name of "muscles of expression."

Their play, it is true, does make up about two-thirds of the wonderful
shifting of relations, which makes the human countenance the most
expressive thing in the world; but their original business is something
totally different. Primarily considered, they are solely for the purpose
of opening or closing, contracting or expanding, the different orifices
which, as we have seen, appear upon the surface of the face. This
naturally throws them into three great groups: those about and
controlling the orifice of the alimentary canal, the mouth; those
surrounding the joint openings of the air-tube and organ of smell, and
those surrounding the eyes.

As there are some twenty-four pairs of these in an area only slightly
greater than that of the outspread hand, and as they are capable of
acting with every imaginable grade of vigor and in every possible
combination, it can readily be seen what an infinite and complicated
series of expressions--or, in other words, indications of the state of
affairs within those different orifices--they are capable of. Only the
barest and rudest outlines of their meaning and principles of
interpretation can be attempted. To put it very roughly, the main
underlying principle of interpretation is that we make our first
instinctive judgment of the site of the disease from noting which of the
three great orifices is distorted furthest from its normal condition.
Then by constructing a parallel upon the similarity or the difference of
the lines about the other two openings, we get what a surveyor would
call our "lines of triangulation," and by following these to their
converging point can often arrive at a fairly accurate localization.

The greatest difficulty in the method, though at times our greatest
help, is the extraordinary and intimate sympathy which exists between
all three of these groups. If pain, no matter where located, once
becomes intense enough, its manifestations will travel over the
face-dial, overflowing the organ or system in which it occurs, and eyes,
nostrils, and mouth will alike reveal its presence. Here, of course, is
where our second gre