tion of what was before partially learned from their osteology and the little that was known of their embryological features, viz., that there must have been a root-stock out of which, in an unmeasured past, arose both the reptilia and the earliest mammals. But a new fact of even larger interest and carrying us inconceivably further back, taking us indeed, with something like clear light, to the origin of the vertebrates themselves, is presented to us by Mr. W. Baldwin Spencer, of the University Museum, Oxford. Mr. Spencer only presents the facts, but their bearing on the philosophy of evolution is apparently inevitable; and certainly they are inexplicable save by this hypothesis."
Then follows an account, for which we have not space, of the discovery, imbedded in the skull of a vertebrate animal, of an invertebrate eye—an atrophied organ, devoid of all function, but pointing to the conclusion, in Dr. Dallinger's words, "that the tunicates and the vertebrates arose in one stock of enormous antiquity." The above extract, however, is chiefly significant for the emphasis with which it asserts the dominion that the Darwinian philosophy has acquired over the minds of competent students of science, and the extent to which it is inspiring and directing their labors. In the face of such powerful testimony, how petty seems the quibble about "the sagacious tact of most naturalists" having decided that "within the historic period" the limits of "well-defined species" have not been changed! Whatever most naturalists may think on this altogether secondary point, it is abundantly evident that they accept the Darwinian theory as a whole, and make it a guiding light in biological research. Any one who wishes to see in what esteem Darwinism is held among men who occupy themselves with the study of organic nature need only turn to the proceedings of learned societies, and he will there see that Darwinism, or, as Dr. Dallinger happily expresses it, "the philosophy of the 'Origin of Species,'" is almost universally accepted as the starting-point of biological speculation. Its general principles will be found to be either tacitly assumed or expressly acknowledged, in nearly every contribution made to those sciences on which it has any bearing. How wide is the range of its application may partly be judged from the following summary, taken from "Nature" of October 23, 1884, of an essay read by Dr. Kirchhoff, of Halle, at the Magdeburg meeting of the Association of German Naturalists and Physicians, on the subject of "Darwinism and Racial Evolution":
"It was argued that the physical development of peoples was intimately dependent on the natural conditions of their respective surroundings. The inhabitants of northern lands are noted for a preponderance of the pulmonary functions; those of hot, moist, tropical regions for a more marked activity of the liver. Thus, the strongest lungs prevail among the Mexicans, Peruvians, and Thibetans, who occupy the three highest plateaus on the surface of the globe. . . . The daily pursuits of a people are constantly evoking special organic
