We are urged to subject ourselves to periodic physical examinations. Yet it is quite as important to keep our minds in good condition as our houses, our consciences or our bodies. Error is as contagious as disease. A false belief may make more trouble in the world than a wrong intention. Vacation is a good time to overhaul your brain from the frontal lobe to the cerebellum. Review your axioms, revise your postulates, and reconsider the unexpressed minor premises of your habitual forms of logic. All your reasoning, however correct, all your knowledge, however great, may be vitiated by some fundamental fallacy, carelessly adopted Get a and uncritically retained. lamp and peer into all the dark corners of your mind. No doubt, you keep the halls and reception rooms that are exposed in conversation to your friends in fairly decent and creditable order. But how would you like to let them look into your cere bral garret and subliminal cellar, where the toys of childhood and the prejudices you inherited from your ancestors mold and rot? Hunt out and destroy with great care every old rag of superstition, for these are liable at any time to start that spontaneous combustion of ideas we call fanaticism against which there is no insurance. The bigger the brain the more dangerous such things are, for they have the more fuel. A little decaying superstition in the mind of a great man has been known to conflagrate a nation. Errors breed errors. They multiply like microbes, especially through neglect. A single false belief may infect all the sound facts you pile in on top of it. Better an empty room than a rubbish heap. In the words of our American philosopher, Josh Billings, "it is better not to know so many things than to know so many things that are not so. Go systematically through your intellectual equipment and see wherein it is deficient. Add annuals to your mental cyclopedia. Pick up each one of the sciences where you left off at school and bring it down to date. Look over the fields of art and literature to see what you have missed or misconceived. Don't let your sociol ogy get too far behind the age. See that your philosophy and psychology bear the same date as the calendar. Examine your religious creed in the light of modern knowledge to see if it needs revision. Take down the atlas and consider how long it has been since you heard from each country. Visit the planets in turn. Take another view of ancient history through the telescope provided by modern scholarship. This inspection of one's stock of ideas is necessary because they do not keep as if they were in cold storage. They do not remain unchanged when stored away and neglected. There is a lot of thinking going on in our brains that we do not know anything about. Ideas are apt to sprout or spoil, like potatoes in a cellar. Facts will ferment from yeasty thoughts until they intoxicate the brain. Falsehoods generate ptomaines, poisoning the mind and producing inexplicable disease and death. You can not be too careful. Clean out your mind at least once a year. SCIENTIFIC ITEMS WE record with regret the death of Alexander Graham Bell; of Simon Nelson Patten, long professor of political economy in the Univer sity of Pennsylvania; of Jokichi Takamine, the industrial research chemist; of Jacobus Cornelius Kapteyn, professor of astronomy at Groningen; of Wilhelm Wislicenus, director of the chemical laboratory at Tübingen; and of Jacques Bertillon, the French statistician. THE CONSERVATION AND PROPER UTILIZATION OF OUR NATURAL __289 Evolution Working Backward; Atoms of Light; The Little Enemies of Man; The Birthplace of the Eels; The Total Solar Eclipse of September 21; Scientific THE SCIENTIFIC MONTHLY OCTOBER, 1922 THE CONSERVATION AND PROPER UTILIZATION OF OUR NATURAL RESOURCES1 By Dr. BARTON WARREN EVERMANN DIRECTOR OF THE MUSEUM OF THE CALIFORNIA ACADEMY OF SCIENCES THE HE natural resources of the United States are the richest and most varied of any country in the world. It is only necessary to call attention to our great coal and oil fields and natural gas, our varied mineral resources, wonderful forests of hard and soft woods, our multitude of species of wild game mammals and birds and fur-bearing animals, the hundreds of species of useful insectivorous and predaceous birds, and the rich fisheries of our Atlantic, Gulf and Pacific coasts, Great Lakes and other interior waters, to enable us to realize that our country has been exceedingly blessed in this regard. And this very richness of natural resources has had much to do with making us the most short-sighted, the most extravagant and the most wasteful people in all the world. There is not one of our natural resources which, in the beginning of the development of the country, was not handled in very wasteful ways; in numerous instances so wasteful and destructive that the resource was wiped out almost, if not quite, entirely. Such were the Buffalo, Wild Pigeon, Atlantic Salmon, Wild Turkey, Gray Squirrel, Sturgeon, Sea Otter, natural gas, white pine and many others that might be mentioned. It is now too late to do anything to correct the mistakes with some of the species that were once valuable assets to our people, because they are now entirely extinct, or are species whose wellbeing depends upon an environment which has passed and can not be restored. But there are many species of the native flora and fauna with which it is not too late and which, with proper care, 1 Presidential address delivered June 22, 1922, at the Salt Lake City meeting of the American Association for the Advancement of Science. Vol. XV.-19. can again be restored to something like their former abundance and usefulness. THE FORESTS It was my good fortune to be brought up in the middle Wabash Basin, a region in which was then found perhaps the greatest hardwood forest the world has ever seen. Great oaks, hickories and elms, each of several species, magnificent sycamores, black walnuts, yellow poplars or tulip trees, splendid gray ash and swamp ash, three or more species of maples or sugar-trees, poplars or cottonwoods of half a dozen species, some of them magnificent trees, and, scarcely less in size and value, but not at all in interest and beauty, were many others that might be named if time permitted. No other forest so rich in species and individuals of commercially important and esthetically interesting trees has ever existed elsewhere in the world. And the pity of it all is that the pioneers of those days never realized what a wonderful asset they had in their great forests. They regarded the forest simply as a source of supply for firewood and the small amount of logs and lumber they needed for buildings, fences and the like, and as something that must be got rid of as soon as possible in the interests of agricultural development. I have seen many a barn built largely, if not wholly, of black walnut logs; and I later saw some of those same barns and stables torn down and the walnut logs hauled away to the sawmill to be converted into high-priced lumber. On my own father's farm and on many others in the same county, there were thousands of walnut rails in the Virginia worm fences with which the farms and fields of those days were enclosed. In the early seventies, black walnut became so valuable that even the stumps were dug out and shipped away to furniture manufacturers. The wastefulness in clearing the land was almost beyond belief. Little or no effort was made to save any of the timber except that needed for immediate use. When a piece of land was to be cleared, all the trees were first girdled thus creating a deadening. Then the trees of whatever kind were felled or burnt down, after which the trunks were cut or burnt ("niggered off") into logs of lengths for convenient handling. With teams of horses or oxen, these logs were then snaked around and piled into great log-heaps, four logs on the ground constituting the bottom layer, three on top of these, two on top of them, and finally one at the top. Each log-heap would thus consist of 10 logs, with small limbs, chunks and trash filling the interstices to serve as kindling when the heaps were to be burned. So heavy and dense was the forest that there would be scores of these great heaps on every acre, each heap made |