Great nervous excitement is possible, every one knows, without muscular tension; therefore in all these motions for gaining freedom and a better physical equilibrium in nerve and muscle, the warning cannot be given too often to take every exercise easily. Do not work at it, go so far even as not to care especially whether you do it right or not, but simply do what is to be done without straining mind or body by effort. It is quite possible to make so desperate an effort to relax, that more harm than good is done. Particularly harmful is the intensity with which an effort to gain physical freedom is made by so many highly strung natures. The additional mental excitement is quite out of proportion to the gain that may come from muscular freedom. For this reason it is never advisable for one who feels the need of gaining a more natural control of nervous power to undertake the training without a teacher. If a teacher is out of the question, ten minutes practice a day is all that should be tried for several weeks. XIII. TRAINING FOR MOTION "IN every new movement, in every unknown attitude needed in difficult exercises, the nerve centres have to exercise a kind of selection of the muscles, bringing into action those which favor the movement, and suppressing those which oppose it." This very evident truth Dr. Lagrange gives us in his valuable book on the Physiology of Exercise. At first, every new movement is unknown; and, owing to inherited and personal contractions, almost from the earliest movement in a child's learning to walk to the most complicated action of our daily lives, the nerve centres exercise a mistaken selection of muscles,--not only selecting more muscles than are needed for perfect co-ordination of movement, but throwing more force than necessary into the muscles selected. To a gradually increasing extent, the contracting force, instead of being withdrawn when the muscle is inactive, remains; and, as we have already seen, an arm or leg that should be passive is lifted, and the muscles are found to be contracted as if for severe action. To the surprise of the owner the contraction cannot be at once removed. Help for this habitual contraction is given in the preceding chapter. Further on Dr. Lagrange tells us that "Besides the apprenticeship of movements which are unknown, there is the improvement of already known movements." When the work of mistaken selection of muscles has gone on for years, the "improvement of already known movements," from the simplest domestic action to the accomplishment of very great purposes, is a study in itself. One must learn first to be a grown baby, and, as we have already seen, gain the exquisite passiveness of a baby; then one must learn to walk and to move by a natural process of selection, which, thanks to the contractions of his various ancestors, was not the process used for his original movements. This learning to live all over again is neither so