_Muscles worth Developing._--When men and women are carefully compared, it is found that women, muscularly weaker as a whole, are most notably so as regards the arms, the muscles of respiration, and the muscles of the back. The muscles of the legs, and especially of the thighs, are relatively stronger. In these facts we can find some practical guidance. The muscles of all the limbs may be left comparatively out of account; whether naturally weak or naturally strong they are of subordinate importance. On the other hand, it is always worth while to cultivate the muscles of respiration, as it is always worth while to keep the heart in good order. Again, the weakness of the muscles of the back, and more especially in the case of the growing girl, is not a thing to be accepted as readily as the weakness of the biceps and the forearm muscles. Various observers find a proportion of between 85 per cent. and 90 per cent. of those suffering from lateral curvature of the spine to be girls, the great majority of these cases occurring between the ages of ten and fifteen. Everywhere it is our duty to prevent such cases, and everywhere physical training will find only too abundant opportunities for endeavouring to correct them. It may be doubted perhaps whether we may rightly follow Havelock Ellis in attributing woman's liability to backache to the relative weakness of the muscles of the back, for we know how often this symptom depends upon not muscular but internal causes peculiar to woman. On the other hand, we may certainly follow Havelock Ellis when he says, regarding this lateral curvature of the spine, from which so many girls and women suffer: "There can be no doubt that defective muscular development of the back, occurring at the age of maximum development, and due to the conventional restraints on exercises involving the body, and also to the use of stays, which hamper the freedom of such movements, is here a factor of very great importance." We shall not here concern ourselves with the details of practice, but the principle is to be laid down that perhaps second only in importance to the right development of the heart and the muscles of respiration is that of the muscles of the back. Always, however, we are apt to judge by the obvious and to value it unduly. Nature makes the biceps and the muscles of the forearm naturally the weakest in woman compared with man, but it is just the bending of the elbow that makes a good show on a horizontal bar or rope; and so we devote too much time to the training of these muscles in our girls, with the results which make such creditable exhibitions at the end of the session, while we forget the muscles of the back, the right development of which is far more valuable, but does not lend itself to display.