Fear

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1896 edition. Excerpt: ...quelquefois trop.' Descartes told us this two hundred years ago. If we bend the forearm forcibly against the upper arm, as though to touch the shoulder with the clenched fist, we notice at once that our hand trembles, because the discharges, by means of which the contractions are produced and regulated, do not exactly answer their purpose. If we press the butt of the musket too firmly against our shoulder, or shoot with a heavy gun, we hit the mark less easily because of the trembling of our arms. We may, however, in a great measure correct these physiological imperfections; thus it is that a few months of practice in drawing will enable anyone to draw straight lines and to outline with a firm touch. In order to understand the whole mechanism of trembling, we must remember that in grasping an object, we not only make use of those muscles which bend the fingers but also of those which serve to open the hand. The work of the muscles which oppose a movement, and which are therefore called antagonistic, is extremely efficacious, and is indeed indispensable in order to graduate and regulate muscular actions with accuracy. When we wish to move our eyes, all the muscles enter into tension, but one prevails and guides them to the desired point. When we take hold of thef pen to Write, we do not only bend the flexors of the'/ fingers but also involuntarily contract the extensors? Without this it would be impossible suddenly to arrest the hand, the eyes, or any other part of the body im rapid motion; Exhaustion or over-excitement of the nerve-centresv destroys the harmony of aim of muscular contractions The hand trembles, because the tension of the flexors and extensors is no longer evenly and firmly, but jerkily maintained. If we...