the axis-cylinder processes of the pyramidal cells in the psycho-motor zone. Along this path the impulse of the will travels. So, when we desire to articulate this or that sound, we transmit the order to act to this or that group of motor mechanisms selected from among them all. But, while the ready-made mechanisms which correspond to the various possible movements of articulation and phonation are connected with the causes (whatever these may be) which set them to work in voluntary speech, there are facts which put beyond all doubt the linkage of these same mechanisms with the auditory perception of words. First of all, among the numerous varieties of aphasia described in clinical reports, we know of two (Lichtheim's 4th and 6th forms) which appear to imply a relation of this kind. Thus, in a case observed by Lichtheim himself, the subject had lost, as the result of a fall, the memory of the articulation of words, and consequently the faculty of spontaneous speech; yet he repeated quite correctly what was said to him.[1] On the other hand, in cases where spontaneous speech is unaffected, but where word deafness is absolute and the patient no longer understands what is said to him, the faculty of repeating another person's words may still be completely retained.[2] It may be said, with Bastian, that these phenomena merely point to a fatigue of the articulatory or auditive
