The development of the auditory functions points to the same close connection of sound and movement. Sounds affect us as tone, and as impulse. The primitive sensation was one of impulse alone, mediated by the "shake-organs." These shake- organs at first only gave information about the attitude and movements of the body, and were connected with motor centres so as to be able to reestablish equilibrium by means of reflexes. The original "shake-organ" developed into the organs of hearing and of equilibrium (that is, the cochlea and the semicircular canals respectively), but these were still side by side in the inner ear, and the close connection with the motor centres was not lost. Anatomically, the auditory nerve not only goes to those parts of the brain whence the motor innervation emanates, and to the reflex centres in the cerebellum, but passes close by the vagus or pneumogastric nerve, which rules the heart and the vasomotor functions. We have then multiplied reasons for the singular effect of sound on motor reactions, and on the other organic functions which have so much to do with feeling and emotion. Every sound-stimulus is then much more than sound-sensation. It causes reflex contractions in the whole muscular system; it sets up some sort of cardiac and vascular excitation. This reaction is in general in the direction of increased amplitude of respiration, but diminution of the pulse, depending on a peripheral vaso-constriction. Moreover, this vasomotor reaction is given in a melody or piece of music, not by its continuity, but for every one of the variations of rhythm, key, or intensity,--which is of interest in the light of what has been said of the latent motor image. The obstacle in syncopated rhythm is physiologically translated as vaso-constriction. In general, music induces cardiac acceleration. All this is of value in showing how completely the attention- motor theory of rhythm applies to the rhythm of sounds. Since sound is much more than sound, but sound-sensation, movement, and visceral change together, we can see that the rhythmical experience of music is, even more literally and completely than at first appeared, an EMBODIED expectation. No sensorial rhythm could be so completely induced in the psychological organism as the sound-rhythm. In listening to music, we see how it is that we ourselves, body and soul, seem to be IN the rhythm. We make it, and we wait to make it. The satisfaction of our expectation is like the satisfaction of a bodily desire or need; no, not like it, it IS that. The conditions and causes of rhythm and our pleasure in it are more deeply seated than language, custom, even instinct; they are in the most fundamental functions of life. This element of music, at least, seems not to have arisen as a "natural language." IV