I do not say that there are no ethnological facts--it may be that we occasionally find ethnological theories--in the Greek writers subsequent; I only state that they by no means answer the expectations raised by the names of the authors, and the opportunities afforded by the nature of their subjects. Something is found in Hippocrates in the way of theory as to the effect of external condition, something in Aristotle, something in Plato--nothing, however, by which we find the study of Man as an animal recognized as a separate substantive branch of study. More than this--in works where the description of new populations was especially called for, and where the evidence of the writer would have been of the most unexceptionable kind, we find infinitely less than there ought to be. How little we learn of Persia from the Cyropædia, or of Armenia from the Anabasis--yet how easily might Xenophon have told us much!
Amongst the successors of Aristotle, we find none who writes a treatise περὶ βαρβάρων--yet how natural the subject, and how great the opportunities!--great, because of the commerce of the Euxine, and the institution of domestic slavery: the one conducting the merchant to the extreme Tanais, the other filling Athens with Thracians, and Asia Minor with Africans. The advantages which the Greeks of the age of Pericles neglected, are the advantages which the Brazilian Portuguese neglect at present, and which, until lately, both the English and the States-men of America neglected also. And the loss has been great. Like time and tide, ethnology waits for no man; and, even as the Indian of America disappears before the European, so did certain populations of antiquity. The process of extinction and amalgamation is as old as history; and whole families have materially altered in character since the beginning of the historical period. The present population of Bulgaria, Wallachia, and Moldavia is of recent introduction. What was the ancient? “Thracians and Getæ” is the answer. But what were they? “Germans,” says one writer; “Slavonians,” another; “an extinct race,” another. So that there is doubt and difference of opinion. Yet we know some little about them in other respects. We know their political relations; a little of their creed, and manners; the names of some of their tribes. Their place in the classification of the varieties of our species we do _not_ know; and this is because, though the Greeks wrote the _civil_, they neglected the _physical_ history of Man.