Two things will disclose the strength or weakness of a bank and the soundness or unsoundness of a nation's banking policy, namely, a financial crisis or an expert audit. A searching audit that analyzes each debit and each credit frequently shows that a bank is solvent only because it is not asked to pay its debts. It continues to do business so long as no obvious weaknesses appear, analogous to measles, adenoids, or paralysis. A frequent disorder of banking results from doing too big a business on too little capital, in making too many loans for the amount of cash held ready to pay depositors upon demand. This disorder always comes to light in a crisis--too late. It can be discovered if looked for in advance of a crisis. Many individuals and communities are likewise physically solvent only because their physical resources are not put to the test. Weaknesses that lie near the surface can be discovered before a crisis by physical examination for individuals and sanitary supervision for communities. Whether individuals or communities are trying to do too much business for their health capital, whether the health reserves will pay debts that arise in a crisis, whether we are ill or well prepared to stand a run on our vitality, can be learned only by carefully analyzing our health reserves. Health debits are compared with health credits for individuals by vitality tests, for communities by vital statistics. Of the many vitality tests none is practicable for use in the ordinary class room. Scientific training is just as necessary for such tests as for discovering the quality of the blood, the presence or absence of tubercle bacilli in the sputum, diphtheria germs in throat mucus, or typhoid germs in milk. But scientific truth, the results of scientific tests, can be made of everyday use in all class rooms. State and national headquarters for educators, and all large cities, can afford to engage scientists to apply vitality tests to school children for the sake of discovering, in advance of physical breakdown and before outward symptoms are obvious, what curriculum, what exercise, what study, recreation, and play periods are best suited to child development. It will cost infinitely less to proceed this way than to neglect children or to fit school methods to the loudest, most persistent theory. The ergograph is an interesting strength tester. It takes a picture (1) of the energy exerted, and (2) of the regularity or fitfulness of the manner in which energy is exerted. Perhaps the time will come when science and commerce will supply every tintype photographer with an ergograph and the knowledge to use it. Then we shall hear at summer resorts and fairs, "Your ergograph on a postal card, three for a quarter." We can step inside, harness our middle finger to the ergograph, lift it up and down forty-five times in ninety seconds, and lo! a photograph of our vitality! If we have strong muscles or good control, the picture will be like this: