twitching movement. The arms may be protruded, as if to avert
some dreadful danger, or may be thrown wildly over the head.
* * * In other cases there is a sudden and uncontrollable tendency
to headlong flight; and so strong is this that the boldest soldiers
may be seized with a sudden panic. As fear rises to an extreme pitch,
the dreadful scream of terror is heard. Great beads of sweat
stand on the skin. All the muscles of the body are relaxed.
Utter prostration soon follows, and the mental powers fail.
The intestines are affected. The sphincter muscles cease
to act and no longer retain the contents of the body.
* * * Men, during numberless generations, have endeavored
to escape from their enemies or danger by headlong flight,
or by violently struggling with them; and such great exertions
will have caused the heart to beat rapidly, the breathing to
be hurried, the chest to heave, and the nostrils to be dilated.
As these exertions have often been prolonged to the last extremity,
the final result will have been utter prostration, pallor, perspiration,
trembling of all the muscles, or their complete relaxation.
And now, whenever the emotion of fear is strongly felt, though it
may not lead to any exertion, the same results tend to reappear,
through the force of inheritance and association"[*] (Fig. 12).


[*] Darwin: Expression of the Emotions in Man and Animals.


In an experimental research, we found evidence that the physiologic
phenomena of fear have a physical basis. This evidence is found
in the morphologic alterations in the brain-cells, which are similar
to those observed in certain stages of surgical shock and in fatigue