Page:Christian Greece and Living Greek.djvu/284

262 CHRISTIAN GREECE AND LIVING GREEK. the vocal organs in speaking ; the visual centre, by which the written words are seen; and the writing centre, which guides the motions of the hand in writing. The centres are capable of individual development by practice. Certain pathological conditions instruct us in the relative importance of each of these centres in the differ- ent ways of using language. The loss occa- sioned by the destruction of any language centre is an indication of the defect that must result from neglecting to cultivate the same centre by prac- tice. When the auditory centre is aroused by impulses coming from the ears, we have the sen- sation of sound; when it is aroused by nerve currents, not from the ears but from other parts of the brain, we have only the memory of sound. For a word to be understood, the auditory centre alone is not sufficient. The sound must awaken the memories of other sensations. The nerve currents passing from one centre to another are called association impulses. Prompt and strong associations must be cultivated as a means of securing clear and vivid ideas. The auditory centre is the first language centre to be devel- oped. A child first hears, then understands the sound of a few words, then it imitates the sounds it understands, and soon can use them.