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Page:Popular Science Monthly Volume 21.djvu/339

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THE PHYSIOLOGY OF EXERCISE.

nervous system comes into consideration in most composite movements. The sight, the sense of pressure, and the muscular sense, and finally the mind, must be prepared to take in the position of the body at each instant, so that the muscles may be in a proper state of adjustment; this is plainly shown in the exercises of fencing, playing billiards, rope-dancing, vaulting on horses in motion, or leaping down a mountain slope. Thus not only the motor, but the sensor nervous system also, and the mental functions, are capable of being exercised and need it; and the muscles again appear to acquire a deeper importance in gymnastics. What is said here of the coarser bodily movements applies equally to all skilled work, of the highest as well as of the lowest kind. Although a Liszt, or a Rubinstein, without an iron muscularity of arm, can not be thought of, and although, likewise, the movements of Joachim's bow during a symphony may correspond to many kilogramme metres, still their power as virtuosos resides in their central nerve-system. The readiness of the turner, the machinist, the watchmaker; of the glass-blower and glass-polisher; the skill of the anatomist and surgeon; writing and drawing; womanly labors like sewing and knitting, crocheting and lace-making; finally, the hardly considered yet more or less artful performances of daily life, dressing and undressing, the use of the sponge, comb and brush, knife and fork—what are they all at last but acquired concatenations of the actions of ganglion cells which, after they have often run on in an appointed course, now succeed each other in the same manner with qualified facility, catching into each other, pausing and resuming again, like the voices in an artfully composed concert? When Lessing asked whether Raphael would have been any the less a great painter if he had been born without hands, he perceived this truth. Is it necessary to add that the same principle applies to all the movements as well as to those of the hands; that, for example, vocal culture rests upon no other one? Singers need not only flexible vocal cords, strong respiratory and laryngeal muscles, ringing resonance of the air-passages—all these would in themselves alone be of no more use to them than a Stradivarius violin to a wood-cutter—their talent has its root in the gray substance at the base of the fourth ventricle. Here also is concealed, but awaiting a higher command, exercising its functions through the hinder third of the left third convolution, the machinery of the speech mechanism, as bulbar paralysis sadly teaches.

It is very remarkable in all these processes that the more any composite movement is practiced, the more unconscious is the act of the nervous system directing it, until at last the latter can not be distinguished from spontaneous nervous mechanisms like the involuntary reflex and by-movements. Erasmus Darwin remarked that, when any one learns to turn, each movement of the hands seems at first to be directed by the will, but that at last the action of the hands becomes so at one with the effect that the turner's will seems to reside in the