There is no calling of the unmarried woman where vigorous health and strength--not great or herculean, but simply such as every well-built and well-developed woman ought to have--would not be of great, almost priceless value to her. The shop-girl, the factory operative, the clerk in the store, the book-keeper, the seamstress, the milliner, the telegraph operator, are all confined, for many hours a day, with exercise for but a few of the muscles, and with the trunk held altogether too long in one position, and that too often a contracted and unhealthy one. Actually nothing is done to render the body lithe and supple, to develop the idle muscles, to deepen the breathing and quicken the circulation--in short, to tone up the whole system. No wonder such a day's work, and such a way of living, leaves the body tired and exhausted. It would, before long, do the same for the strongest man. No wonder that the walk to and from work is a listless affair. No wonder that, later on, special or general weakness develops, and the woman goes through life either weak and delicate, or with not half the strength and vigor which might readily be hers. And is it any better with the married woman? Take one of limited means. Much of the work about her home which servants might do, could she employ them, she bravely does herself, willing to make ten times this sacrifice, if need be, for those dearest to her. Follow her throughout the day, especially where there are children: there is an almost endless round of duties, many of them not laborious, to be sure, or calling for much muscular strength, but keeping the mind under a strain until they are done, difficult to encompass because difficult to foresee. In the aggregate they are almost numberless. A man can usually tell in the morning most of what is in front of him for the day--indeed, can often plan so as to say beforehand just what he will be at each hour. But not so the housewife and mother of young children. She is constantly called to perform little duties, both expected and unexpected, which cannot fail to tell on a person not strong. A healthy child a year old will often weigh twenty pounds; yet a woman otherwise weak will carry that child on her left arm several times a day up one or more flights of stairs, till you would think she would drop from exhaustion. Let sickness come, and she will often seem almost tireless, so devotedly will she keep the child in her arms. While children are, of course, carried less when they begin to walk, many a child two, or even three years old, is picked up by the mother, not a few times a day, even though he weighs thirty or forty pounds instead of twenty. Now for this mother to have handled a dumb-bell of that weight would have been thought foolish and dangerous, for nothing about her suggested strength equal to that performance. And yet the devotion of a weak mother to her child is quite as great as that of a strong one. Is it any wonder