inarticulate cries or language, they will likewise be voluntarily
employed, and the habit will thus be strengthened. But whether or not
of service as a means of communication, the tendency to perform
opposite movements under opposite sensations or emotions would, if we
may judge by analogy, become hereditary through long practice; and
there cannot be a doubt that several expressive movements due to the
principle of antithesis are inherited.
CHAPTER III. GENERAL PRINCIPLES OF EXPRESSION _concluded_.
The principle of direct action of the excited nervous system on the
body, independently of the will and in part of habit Change of colour
in the hair Trembling of the muscles Modified
secretions Perspiration Expression of extreme pain Of rage, great joy,
and terror Contrast between the emotions which cause and do not cause
expressive movements Exciting and depressing states of the
mind Summary.
We now come to our third Principle, namely, that certain actions which
we recognize as expressive of certain states of the mind, are the
direct result of the constitution of the nervous system, and have been
from the first independent of the will, and, to a large extent, of
habit. When the sensorium is strongly excited nerve-force is generated
in excess, and is transmitted in certain directions, dependent on the
connection of the nerve-cells, and, as far as the muscular system is
concerned, on the nature of the movements which have been habitually
practised. Or the supply of nerve-force may, as it appears, be
interrupted. Of course every movement which we make is determined by
the constitution of the nervous system; but actions performed in
obedience to the will, or through habit, or through the principle of
antithesis, are here as far as possible excluded. Our present subject
is very obscure, but, from its importance, must be discussed at some
little length; and it is always advisable to perceive clearly our
ignorance.
The most striking case, though a rare and abnormal one, which can be
adduced of the direct influence of the nervous system, when strongly
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