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of the law of natural selection, they are fostered, cared for, and allowed to propagate their kind. "Society preserves for the progenitors of the future alike the weak, the strong, the diseased, and the healthy. If, then, this blind law of natural selection is the one key to progress, man must degenerate." One school of statistical writers maintains that this result does actually appear.

But Mr. Lewis shows conclusively that, while "civilization does largely sacrifice one principle of progress—the law of evolution by survivorship—it introduces another still more potent principle"—longevity. The outcome of careful breeding for a few generations, with a view to improvement in this direction, would produce a people who would live to a patriarchal age. The idea of such stirpiculture as this is repulsive to our present habits of thought. It is probable that the idea will never be realized, but there is a tendency toward something of that kind.

Mr. Lewis truly says that the subject leads us to the door of a world of restless thought and speculation.

The paper is extremely interesting and suggestive.

Elementary Lessons in Physical Geography. By Archibald Geikie, LL. D., F. R. S. London and New York: Macmillan & Co., 1877. Pp. 375. Price, $1.75.

One of the best of the "Science Primer Series" was that of Dr. Geikie on "Physical Geography," which in the present volume is expanded into the form of a text-book for rather more advanced scholars.

The author is undoubted authority on this subject, and may be fully trusted, and his material is well arranged for the purposes of teaching. The illustrations are taken close at hand, and not only show the way in which effects, with which we are familiar, have been produced, but teach the collateral lesson that Nature's processes are uniform; that the most stupendous results of far-away lands or past time have been wrought by the same methods that are in operation here and now. This is a lesson that scientific men were slow to learn, and it has not hitherto been sufficiently taught in our text-books. It is something gained when a boy, watching the little streams of a summer shower making their way through a sand-bank, knows that he is looking on the same forces at work that make and waste a continent.

The book is freely illustrated with good woodcuts, and with maps showing the distribution of atmospheric pressure, temperature, volcanoes and earthquakes, ocean-currents, etc.

Geological and Geographical Survey of Colorado and Adjacent Territory (1875). Pp. 834. Washington: Government Printing-Office.

It would be impossible, within the narrow compass of a book-notice, to summarize the contents of this valuable report; indeed, the space at our disposal would be insufficient even to give a simple list of the many wonderful natural curiosities and interesting ancient ruins here for the first time described and pictured. Then, in addition to the reports of the geologists and togpographers, we have an elaborate monograph on the American bison, by J. A. Allen; and a voluminous report by Dr. A. S. Packard, Jr., on the Rocky Mountain locust and other insects injurious to the field and garden crops of the Western Territories.

Fur-bearing Animals. By Elliott Coues. Pp. 362. With numerous Figures and Plates. Washington: Government Printing-Office.

Dr. Coues has for some time been engaged in preparing a systematic history of the North American mammals, both living and extinct, and the present volume is offered as a specimen of the method of treatment to be adopted in that work. The group of animal forms described in this monograph, the family Mustelidæ, he divides into five sub-families, namely, Mustelinæ (wolverene, marten, weasel), Mephitinæ (skunk), Melinæ (badger), Lutrinæ (otter), Enhydrinæ (sea-otter). The material on which the author bases his systematic classification is sufficiently voluminous, namely, the collections made by Hayden's Survey, of which he is the naturalist, and those of the National Museum at Washington. The purely scientific and technical aspects of the subject-matter are, of course, discussed