6o2 THE POPULAR SCIENCE MONTHLY. 



almost exclusively upon the development of one intellectual center 

 (music upon the auditory, painting upon the visual) ; and one in 

 whom this center is i)oorly developed is deprived of all but medi- 

 ocre 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 x^rocess 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 let- 

 ters, printed characters, script, etc.), and again with a set of mus- 

 cular 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 ex- 

 pressive 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 phys- 

 ical 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 conse- 

 quence of business troubles, he became nervous and irritable. 



