hypotheses, each hypothesis involving multitudes of speculations, all of which evaporate as the truth slowly crystallizes. Speculation is valuable to science only as it directs the mind into otherwise-undiscoverable paths; but when the truth is found, there is an end to speculation. So much for facts in general; let us now look for a moment at the particular class of facts of which this work is a collection. [Sidenote: TENDENCY OF PHILOSOPHIC INQUIRY.] The tendency of philosophic inquiry is more and more toward the origin of things. In the earlier stages of intellectual impulse, the mind is almost wholly absorbed in ministering to the necessities of the present; next, the mysterious uncertainty of the after life provokes inquiry, and contemplations of an eternity of the future command attention; but not until knowledge is well advanced does it appear that there is likewise an eternity of the past worthy of careful scrutiny,--without which scrutiny, indeed, the eternity of the future must forever remain a sealed book. Standing as we do between these two eternities, our view limited to a narrow though gradually widening horizon, as nature unveils her mysteries to our inquiries, an infinity spreads out in either direction, an infinity of minuteness no less than an infinity of immensity; for hitherto, attempts to reach the ultimate of molecules, have proved as futile as attempts to reach the ultimate of masses. Now man, the noblest work of creation, the only reasoning creature, standing alone in the midst of this vast sea of undiscovered truth,--ultimate knowledge ever receding from his grasp, primal causes only thrown farther back as proximate problems are solved,--man, in the study of mankind, must follow his researches in both of these directions, backward as well as forward, must indeed derive his whole knowledge of what man is and will be from what he has been. Thus it is that the study of mankind in its minuteness assumes the grandest proportions. Viewed in this light there is not a feature of primitive humanity without significance; there is not a custom or characteristic of savage nations, however mean or revolting to us, from which important lessons may not be drawn. It is only from the study of barbarous and partially cultivated nations that we are able to comprehend man as a progressive being, and to recognize the successive stages through which our savage ancestors have passed on their way to civilization. With the natural philosopher, there is little thought as to the relative importance of the manifold works of creation. The tiny insect is no less an object of his patient scrutiny, than the wonderful and complex machinery of the cosmos. The lower races of men, in the study of humanity, he deems of as essential importance as the higher; our present higher races being but the lower types of generations yet to come.