and idea, are thus made into distinct wholes of which each is supposed to be self-sufficing. And while, if we really confined ourselves to pure experience, the idea is what we should start from—since it is to the idea that the auditory memories owe their connexion and since it is by the memories that the crude sounds become completed,—on the contrary, when once we have arbitrarily supposed the crude sound to be by itself complete, and arbitrarily also assumed the memories to be connected together, we see no harm in reversing the real order of the processes, and in asserting that we go from the perception to the memories and from the memories to the idea. Nevertheless, we cannot help feeling that we must bring back again, under one form or another, at one moment or another, the continuity which we have thus broken between the perception, the memory and the idea. So we make out that these three things, each lodged in a certain portion of the cortex or of the medulla, intercommunicate, the perceptions going to awaken the auditory memories, and the memories going to rouse up the ideas. As we have begun by solidifying into distinct and independent things what were only phases—the main phases—of a continuous development, we go on materializing the development itself into lines of communication, contacts and impulsions. But not with impunity can we thus invert the true order, and as a necessary consequence, introduce into each term of the series elements which
