474 THE POPULAR SCIENCE MONTHLY.
cises, his muscular sense is refined, and lie becomes aware of a series of new sensations which remain unknown to those who have never handled tools. In this way we account fairly well for im- portant modifications which are produced in the movements by education.
Absolute muscular force, measured by the dynamometer, soon reaches its maximum, and, if we limit ourselves to this gross measure, we shall have but a false idea of physical perfection- ment. It is not, in fact, in the absolute measure of muscular force that a great modification is to be found, but in the aptitude for producing a large sum of work with moderate fatigue and an economical expenditure of force. This refinement is produced in the nervous centers ; through attention sustained by the will, through the frequent repetition of well-defined muscular acts, we are able to reach the point of suppressing useless contractions in the desired movement, and bringing into play only a portion of the muscles which were at first contracted in a mass. To this intelligent distribution of the central nervous excitation in the co-operating groups are added a more perfect tact in appositeness, a surer realization of the direction of the intensity and the dura- tion of the contractions, and a greater promptitude in grasping at once all the conditions of the effort. Thus is realized a perfection- ment of the motor organs which is manifested externally by ad- dress, agility, and sureness of movements, and closely touches upon the higher qualities confidence in one's strength and courage.
Education should not only be applied to movements of precis- ion, but it ought also to have in view economy in the expendi- ture of nervous excitation and mechanical labor ; it ought to tend to reduce useful contractions to a minimum, and in the end to induce automatism by steadily diminishing the part played by attention, which is absolutely necessary in the beginning. Thus the performing musician is not born a virtuoso ; he reaches per- fection of execution on condition of frequently repeating the same exercises. To acquire perfection of skill, he seeks to obtain equality in the motions of his fingers, ease of hand, arm, and the whole body. He performs the details of a cadence slowly, quick- ens it progressively, and thus becomes able at last to maintain accuracy in lively movements. Associations of the nervous cells are doubtless produced in his system, which render easy and automatic certain muscular co-operations that were at first insur- mountably difficult. The visual perception in the musician comes at last to be translated immediately into a movement of the fingers without any effort of the attention. In the boxer or the swordsman, the slightest manifestation of his adversary's inten- tion produces an instinctive determination which is at once re- vealed in the attitude.