One moment let my life blood stream From boyhood's fount of flame! Give me one giddy, reeling dream Of life all love and fame! But every experiment in turning back exalts the present and the future. Gifts as well as problems are seen to come with complexity, and civilization flatly refuses to relinquish these gifts. Sound maturity is better than youth or age: The smiling angel dropped his pen,-- "Why, this will never do; The man would be a boy again, And be a father too!" Problems of health and of civics can never be solved by appealing to Nature Back, when only the few could be healthy, when one baby in three died in infancy, when old age was toothless and childish, when infection ravished nations, when the average life was twenty years shorter than now, and when unspeakable filth was tolerated in air, street, and house. They can all be solved by appeals to Nature Fore, which holds up an ideal of mankind physically able to enjoy all the benefits and to conquer all the dangers of civilization. It is not looking back, but looking in and forward that reveals what natural law promises to those who obey it. By using numerous tests which have been suggested in preceding chapters we can learn how far we and our communities obey natural law when working and playing. Health for health's sake has nowhere been urged. On the contrary, healthful living has been frankly valued for its aid to efficient living by individual and by community; wherefore the emphasis upon others' health and upon the civic aspects of our own health. Tests furnish us with the technic necessary to efficient living; civics, with the larger reason; natural law, with the "pillar of fire by night" to help us choose our path among habits and pleasures whose immediate results upon efficient living cannot easily be determined. Fashions, tastes, mannerisms, personal indulgences, have been left for Agassiz to deal with. Generally speaking, we all know of numerous acts committed and numerous acts omitted in our daily routine that convict us of not living up to our knowledge of physiology and hygiene,--wearing tight shoes or tight corsets, drinking strong coffee, smoking, reading while reclining, failing to insure clean air and clean bodies. Then there are other acts whose omission or commission violate no physical law so far as we can see, but whose unnaturalness we concede,--putting chalk on the eyebrows, wearing false hair or curious puffs, putting perfumery in the bath or on handkerchiefs, assuming artificial poses of body or mouth. These violations of natural law are forced upon us by "style" or "custom" or family convenience. When we come to choose between following fashions and disobeying them, we generally decide that it is better to do a foolish or slightly harmful thing than to occasion criticism, mirth, or even special notice by our dress or our abstemiousness.