Page:Popular Science Monthly Volume 33.djvu/620

602 almost exclusively upon the development of one intellectual center (music upon the auditory, painting upon the visual); and one in whom this center is poorly developed is deprived of all but mediocre achievement in that direction. But a far larger share of mental work is done by the combined use of various centers; and here, in what one does best by using the eye as the leading sense, another may succeed better by employing the ear as the teacher. The learning of one's mother-tongue is probably the best example of the operation in question. (A remark must be here inserted regarding the acquiring and the retaining of knowledge. It may be that one sense acquires knowledge readiest and another retains it best. But the utility of either process is so generally dependent upon the soundness of the other that we have good reason to believe that cases where different senses take charge of the two processes would be the exception. However, the question can only be settled by an experimental test. In general, the different sensory types will be supposed to refer to the combined process of memory and apperception, with the reservation, in necessary cases, of the possible difference just referred to.) In learning a language, one must first associate certain ideas with certain sounds, and again with the accompanying feelings of the vocal apparatus when making the sounds, and again with a certain set of visual symbols (usually more than one set—capitals, small letters, printed characters, script, etc.), and again with a set of muscular feelings when writing. And all this—the work of years—can be further complicated by the knowledge of several languages, of short-hand, and so on. In spite of this wonderfully complex and compact interassociation of the elements of language—as expressive of the intellectual utilization of sense-impressions—each sense keeps its store of images and its apperceptive grasp quite distinct. Pathology demonstrates that the distinctions here made are not abstractions, but have correlated with them separate physical substrata in the cells of various parts of the cortex; disease can paralyze any one of these cell-groups, shutting off one part of the language complex, and leaving all others quite intact. A few cases of this kind will bring out very clearly the distinctions in types of memory and apperception here treated. Dr. Charcot records the most striking case: A highly intelligent gentleman, well versed in several languages, was gifted with a remarkable visual memory. He could read pages of his favorite authors from the mental image of the printed page; he could sketch well from memory; and the mention of a scene in a play or of an incident of any of his many travels at once called up a bright and complete picture of the entire scene. He had, however, no fondness for music, and what he heard impressed him very little. As a consequence of business troubles, he became nervous and irritable.