the rough sketch is to the finished picture. For it is one thing to understand a difficult movement, another to be able to carry it out. To understand it, we need only to realize in it what is essential, just enough to distinguish it from all other possible movements. But to be able to carry it out, we must besides have brought our body to understand it. Now, the logic of the body admits of no tacit implications. It demands that all the constituent parts of the required movement shall be set forth one by one, and then put together again. Here a complete analysis is necessary, in which no detail is neglected, and an actual synthesis, in which nothing is curtailed. The imagined diagram, composed of a few nascent muscular sensations, is but a sketch. The muscular sensations, really and completely experienced, give it colour and life.
It remains to be considered how an accompaniment of this kind can be produced, andEvidence from certain forms of sensory aphasia, in which the motor diagram seems to be affected. whether it really is always produced. We know that in order effectively to pronounce a word the tongue and lips must articulate, the larynx must be brought into play for phonation, and the muscles of the chest must produce an expiratory movement of air. Thus, to every syllable uttered there corresponds the play of a number of mechanisms already prepared in the cerebral and bulbar centres. These mechanisms are joined to the higher centres of the cortex by
