Emotion always causes numerous and intense bodily effects. Furious anger
may cause frowning brows, grinding teeth, contracted jaws, clenched
fists, panting breath, growling cries, bright redness of the face or
sudden paleness. None of these effects is voluntary; we may not even be
conscious of them.

Fright may produce a wild beating of the heart, a death-like pallor, a
gasping motion of the lips, an uncovering or protruding of the
eye-balls, a sudden rigidity of the body as if "rooted" to the spot.

Grief may cause profuse secretion of tears, swollen, reddened face, red
eyes and other familiar symptoms.

Shame may cause that sudden dilation of the capillary blood-vessels of
the face known as "blushing."

[Sidenote: Bodily Effects of Perception]

The sight of others laughing or yawning makes us laugh or yawn. The
sound of one man coughing will become epidemic in an audience. The
thought of a sizzling porter-house steak with mushrooms, baked potatoes
and rich _gravy_ makes the mouth of a hungry man "water."

Suppose I show you a lemon cut in half and tell you with a wry face and
puckered mouth that I am going to suck the juice of this exceedingly
sour lemon. As you merely read these lines you may observe that the
glands in your mouth have begun to secrete saliva. There is a story of a
man who wagered with a friend that he could stop a band that was playing
in front of his office. He got three lemons and gave half of a lemon to