THE PRACTICAL VALUE OF PURE SCIENCE 239 



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 con- 

 tinually, 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 re- 

 sponded by sending down experts: not men trained in boll-weevil 

 methods, for these had to be learned, but men with a good knowl- 

 edge 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 Eussia 

 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 biolo- 

 gists 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 Linnaeus, in the middle of the eighteenth century, 

 by originating the modern method of naming plants and animals, indi- 

 rectly 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- 



