Page:Popular Science Monthly Volume 67.djvu/332

326 powerless area from the other cortical areas, which were under excitement.

Now we know with certainty that increased intensity of the stimulation is followed by increased area of neural excitement. A spreading of the nervous processes on which the initiation of motor impulses depends—whatever the chemico-physical character of those processes may be—would, then, necessarily take place in the center of the N. facialis, in answer to the increased demands made upon it by the more intense stimulation from various higher areas. This spreading would, it is likely, have the double effect of enabling the center to use hitherto unused paths between itself and the center of the accessory nerve; and it might also compel the immature nerve-elements to myelinate themselves in preparation for the discharge of their new functions. When this enlarging area occupied, during its excitement, by the center of the facial nerve, had broken over, so to say, into the center of the accessory nerve, and had made good and useful the newly established connection between the two, then it could virtually resume its old functions of control, although now by a new and more roundabout path.

The assumptions previous to the last would all seem to be helpful, if not needful, to explain some of the features of this case of nerve-anastomosis and sequent recovery from facial paralysis. The last assumption is absolutely essential in order to make any satisfactory progress toward explaining it at all. The other assumptions very speedily bring us to the hitherto impenetrable veil of mystery which is met when any attempt is made to explain the facts of experience by our theories of cerebral physiology or of experimental and physiological psychology. But the last assumption seems somewhat to lengthen the distance to the veil. The picture of the unity in variety of the histological elements, and collections of elements, and of the physiological functions, which belong to the nervous system, offered by such experiences as that of this patient, assists in confirming the views arrived at experimentally by Professor Sherrington and other explorers in this field. But the unity and the variety of this infinitely complex system are not so much matters of wholly predetermined and, so to say, 'made-up' sort, dependent upon unchangeable histological peculiarities externally combined into a whole; they are, the rather, a growth, changeful, adaptable to varying conditions, dependent upon need and use, and conditioned' chiefly, if not wholly, upon the possibility of establishing the necessary connections amongst the differently located elements.

Many of the more important and interesting problems of psychology are suggested by this case of anastomosis. No other group of muscles is so expressive, so responsive to ideas and emotions, as those which