Prof. Halleck says: "By inducing an expression we can often cause its allied emotion.... Actors have frequently testified to the fact that emotion will arise if they go through the appropriate muscular movements. In talking to a character on the stage, if they clench the fist and frown, they often find themselves becoming really angry; if they start with counterfeit laughter, they find themselves growing cheerful. A German professor says that he cannot walk with a schoolgirl's mincing step and air without feeling frivolous." Prof. Wm. James says: "Whistling to keep up courage is no mere figure of speech. On the other hand, sit all day in a moping posture, sigh, and reply to everything with a dismal voice, and your melancholy lingers. If we wish to conquer undesirable emotional tendencies in ourselves, we must assiduously, and in the first instance coldbloodedly, go through the _outward movements_ of those contrary dispositions which we wish to cultivate. Smooth the brow, brighten the eye, contract the dorsal rather than the ventral aspect of the frame, and speak in a major key, pass the genial compliment, and your heart must indeed be frigid if it does not gradually thaw." Dr. Wood Hutchinson, says: "To what extent muscular contractions condition emotions, as Prof. James has suggested, may be easily tested by a quaint and simple little experiment upon a group of the smallest voluntary muscles of the body, those that move the eyeball. Choose some time when you are sitting quietly in your room, free from all disturbing influences. Then stand up, and assuming an easy position, cast the eyes upward and hold them in that position for thirty seconds. Instantly and involuntarily you will be conscious of a tendency toward reverential, devotional, contemplative ideas and thoughts. Then turn the eyes sideways, glancing directly to the right or to the left, through half-closed lids. Within thirty seconds images of suspicion, of uneasiness, or of dislike will rise unbidden to the mind. Turn the eyes on one side and slightly downward, and suggestions of jealousy or coquetry will be apt to spring unbidden. Direct your gaze downward toward the floor, and you are likely to go off into a fit of reverie or abstraction." Prof. Maudsley says: "The specific muscular action is not merely an exponent of passion, but truly an essential part of it. If we try while the features are fixed in the expression of one passion to call up in the mind a different one, we shall find it impossible to do so."