of the feeling. I believe it to be a general law of the mind
that along with the fact of inward feeling or consciousness,
there is a diffusive action or excitement over the bodily members."
In another place he adds, "A very considerable number of the facts
may be brought under the following principle: namely, that states
of pleasure are connected with an increase, and states of pain
with an abatement, of some, or all, of the vital functions."
But the above law of the diffusive action of feelings seems too
general to throw much light on special expressions.

Mr. Herbert Spencer, in treating of the Feelings in his `Principles
of Psychology' (1855), makes the following remarks:--"Fear,
when strong, expresses itself in cries, in efforts to hide or escape,
in palpitations and tremblings; and these are just the manifestations
that would accompany an actual experience of the evil feared.
The destructive passions are shown in a general tension of the
muscular system, in gnashing of the teeth and protrusion of the claws,
in dilated eyes and nostrils in growls; and these are weaker
forms of the actions that accompany the killing of prey."
Here we have, as I believe, the true theory of a large number
of expressions; but the chief interest and difficulty of the
subject lies in following out the wonderfully complex results.
I infer that some one (but who he is I have not been able to ascertain)
formerly advanced a nearly similar view, for Sir C. Bell says,[9]
"It has been maintained that what are called the external signs
of passion, are only the concomitants of those voluntary movements
which the structure renders necessary." Mr. Spencer has also
published[10] a valuable essay on the physiology of Laughter,
in which he insists on "the general law that feeling passing
a certain pitch, habitually vents itself in bodily action,"