But now--and this is the third link of the chain--bodily acts set up mental states, and a man cannot gesticulate or vocalize without feeling the emotions of which his actions are, as we say, expressive. «We feel sorry because we cry,» writes Professor William James in his brilliant, paradoxical way, «angry because we strike, afraid because we tremble;» and whether or not we agree with his extreme view that the mental state is entirely a reverberation of bodily disturbances, we cannot but realize that in all these cases executing the expression tends to give us the feeling. He who persistently smiles will end by being cheerful, and a moderate amount of sighing or groaning will make any one melancholy. Above all, the imitation of vocal movements, such as we all go through at least incipiently when we hear melody, and the «keeping time» that strong dance-music so irresistibly prompts--these actions very noticeably set up in us their appropriate states of feeling. We not only imitate the lip motions and throat contractions of a persuasive speaker or singer, but doing so fills us with the emotion that prompts his utterance. Tired soldiers not only step out to a potently rhythmical tune--that is, they not only imitate the beat--but they actually feel less weary, more energetic, so long as the stimulus lasts. Once a bodily activity is set up, no matter how, it arouses the mental state proper to it; in a word, expression generates emotion. Obviously, then, if in the first place the natural outlets of emotional excitement are bodily motions and vocal sounds, if in the second place the observation of such motions and sounds arouses the impulse to imitate them, and if finally this imitation produces again in the imitator the states of mind which first set the whole process going, then these motions and sounds, these inchoate germs of dance and song, possess an enormous latent power of expression, and need only to be systematized to become a wonderfully eloquent language. Such a language, in fact, is music. II