The relation and reaction above mentioned are interesting not only from the viewpoint of theory but also because of their practicable application in emotional development and training. It is an established truth of psychology that each physical expression of an emotional state serves to intensify the latter; it is pouring oil on the fire. Likewise, it is equally true that the repression of the physical expression of an emotion tends to restrain and inhibit the emotion itself. Halleck says: "If we watch a person growing angry, we shall see the emotion increase as he talks loud, frowns deeply, clinches his fist, and gesticulates wildly. Each expression of his passion is reflected back upon the original anger and adds fuel to the fire. If he resolutely inhibits the muscular expressions of his anger, it will not attain great intensity, and it will soon die a quiet death. * * * Not without reason are those persons called cold blooded who habitually restrain as far as possible the expression of their emotion; who never frown or throw any feeling into their tones, even when a wrong inflicted upon some one demands aggressive measures. There is here no wave of bodily expression to flow back and augment the emotional state." In this connection we call your attention to the familiar and oft-quoted passage from the works of Prof. William James: "Refuse to express a passion and it dies. Count ten before venting your anger and its occasion seems ridiculous. 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. There is no more valuable precept in moral education than this, as all who have experience know: If we wish to conquer undesirable emotional tendencies in ourselves, we must assiduously, and in the first instance cold-bloodedly, go through the outward movements of those contrary dispositions which we prefer 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, and your heart must be frigid indeed if it does not gradually thaw." Along the same lines Halleck says: "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 clinch the fists 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."