and which elevates and protrudes the under lip, was peculiar to
man; but I was deceived. The character of human expression
is in the triangularis oris, or depressor anguli oris, a muscle which
I have not found in any other animal; which I believe to be peculiar
to the human face, and for which I have been able to assign no
other use than what belongs to an organ of expression. It arises
from the base of the lower jaw, and passes up to be inserted with
the converging fibres of almost all the muscles of the side of the face
at the corner of the mouth. It produces that arching of the lip so
expressive of contempt, hatred, jealousy; and in combination with
the elevator of the under lip, and the orbicularis, it has a larger
share than any other muscle in the infinite variety of motion in the
mouth, expressive of sentiment.
When we compare the muscles of the human head with those
of animals, we may perceive many smaller distinctions, into a detail
of which I shall not at present enter. The D e p r e s s o r Al.m N a s i ;
the N a s a i.is L a b i i S u p e r i o r e s ; the descending fibres of the Oc-
c i p i t o - F r o n t a i .i s , are not in the brute; and in general the more
minute and fasciculated structure of all the muscles of the lips, in
the face of man, indicates a decided superiority in the provision for
the motion of the features.
We have already observed, that the chief expression of which
the faces of animals seem capable, are those of rage and of fear.
Even pain is very obscurely indicated, except in the voice, and in
the writhing and struggling of the body.
Eage is expressed most strongly by the carnivorous animals:
in them it is wild, ferocious, and terrifying. In the milder class
of animals the chief expression is such as may be called T o n ic ;
the effect of the excited state of the body. The rage of the carnivorous
animal, so far as it appears in the expression of the face, is
found in the strong action of the ringentes or snarling muscles, the
exposure of the canine teeth, the gnashing of the tusks,, and the
brilliant state of excitement of the eye. The rage of the graminivorous
is chiefly to be found in the eye, and in the inflation of the
nostril. The expression of human rage participates of both these;
the corresponding muscles of the lips and nostril, producing a
similar action with that of animals; an exposure and gnashing of
the teeth; a degree of sparkling of the eye, and an inflation of the
nostril. And of a face under the influence of such action, a spectator
would infallibly say, that the aspect is perfectly brutal, savage,
and cruel. Eut when the corrugator supercilii, a muscle peculiar
to human expression, is brought into action, the sign is altered.
The eyebrows are knit, the energy of mind is apparent, and the
mingling of human thought and emotion with the savage and brutal
rage of the mere animal.
In man, the action of the frontal muscle, and corrugator supercilii,
and of the orbicular muscle of the mouth, bestows a great