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Page:Popular Science Monthly Volume 73.djvu/243

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tain lands, and the available water will decrease, because the timber helps to hold the water supply and to prevent floods. In any way change the face of nature, as man by his habits must needs to do continually, and more or less serious results must follow. As an instance we may consider the cotton boll weevil, a subject that is a remarkably earnest one in Texas. This insect originated in Central America and has spread northward; several years ago the natural barriers to its spread were broken down and consequently it has extended its feeding area. When it first appeared in Texas all sorts of rough remedies were applied, but in vain; then the help of the National Department of Entomology of the Bureau of Agriculture was called in. They responded by sending down experts: not men trained in boll-weevil methods, for these had to be learned, but men with a good knowledge of general entomology, ready to attack the matter as they would any scientific problem. First they proceeded to determine the life history, egg-laying habits, duration of the different developmental stages, number of broods, overwintering; then, knowing these facts, they could decide at what stage the injury may be most successfully fought. The method is of the first importance and this was given by pure science, and in a way the method of meeting the boll weevil is not unlike the method of fighting a parasite of the human body. The next step was to ascertain the natural animal and plant enemies of the pest, and to try to increase these enemies. Thus the field mice in Russia have been reduced by infecting them with pathogenic bacteria, and the "green-bugs" of wheat by increasing the number of lady beetles. These are the general methods of meeting any such practical questions. Farmers may laugh at naturalists, but they are wholly dependent upon them when such emergencies arise. Most of us are likely to smile at the man who collects and describes insects, counting the number of joints in the antennas of a bug, of hairs upon the forehead of a bee, or the arrangement of the veins upon the wing of a moth. Most people would hold that such a being is wasting his time in a foolish hobby. But I wish to drive the fact very firmly home, that the collecting and naming of animals and plants, occupations that even many biologists pity, are really fundamental for biology and therefore for the sciences that rest upon biology. For the study of animals and plants had reached a standstill, a stagnation, for want of a proper concise method of naming the numerous species that were being made known, until the great Swede Linnæus, in the middle of the eighteenth century, by originating the modern method of naming plants and animals, indirectly made possible advance in agriculture as well as in biology. The more our knowledge advances the greater grows the need of accurate determinations of species. Without systematic describers of species agriculture would be a hopeless matter. Thanks to the labors of gen-