When a grammar-school boy I learned from the game "Quotations" that Louis Agassiz, scientist, had written the sentence with which I introduce a final appeal for living that will permit physical and civic efficiency. Agassiz has been called "America's greatest educator," and again "the finest specimen yet discovered of the genus _homo_, of the species _intelligens_." The story of his long life as teacher of teachers reads like a romance. But among his gifts to education and citizenship none can be made to mean more than the simple proposition that natural law is as sacred as a moral principle. All who remember this "beatitude" will be helped to solve many perplexing problems of dress, diet, play, education, philanthropy, morals, and civics. Reverence for the natural carries with it a distaste for the unnatural. Those who obey natural law soon come to regard its violation as a nuisance when not immoral. On the other hand, compromise with the unnatural, like compromise with vice, quickly leads first to toleration and thence to interest and practice. Therefore the importance of giving children Agassiz's conception of the sacredness of the laws that govern the human body. A passion for the natural is a strong foundation for habits of health and a priceless possession for one who wishes to know morality in its highest sense. "Natural" is less attractive to us than it would be had Agassiz first interpreted it for us rather than Rousseau or present-day exponents of "the simple life," "back to nature," and "back to the land." It is too often forgotten that no one sins against natural law more grievously than the primitive man or the isolated man in daily contact with non-human nature. Communing with nature seems not only to require communing with man but to give joys in proportion as the nature lover is concerned for the human society of which he is a part. Natural law does not become a moral principle until man is benefited or injured by man's use of nature's resources within and about him. Natural living according to natural law must be something sounder, more beautiful, and more progressive than can be read into or out of mountains, trees, brooks, and sky, or primitive society. Natural law points to a Nature Fore as well as a Nature Back, to a Nature Up and Beyond as well as a Nature Down and Behind. The Nature that was yesterday will not do for to-morrow, any more than a man is willing to give up his nature aspirations for the careless, animal ways of romping childhood. Civilization is constantly urged at each step to repeat the prayer of Holmes's old man who dreams for the Autocrat of the Breakfast Table: Oh for one hour of youthful joy! Give back my twentieth spring! I'd rather laugh a bright-haired boy Than reign a gray-beard king! Off with the wrinkled spoils of age! Away with learning's crown! Tear out life's wisdom-written page, And dash its trophies down!