considerable detail and with many illustrations. But these chapters are not a mere collection of facts. The bearing of these relics and ruins on the question of man's antiquity and his early migrations is shown. A much debated question—more in debate formerly than now perhaps—is that of the "specific" unity of man. Is man a single zoological species, divided into races, that is, varieties, or is he a genus divided into species? From a study of race crossing, from anatomical resemblances, from psychic unity and on physiological grounds, the author concludes that man is one species, and that his subdivisions are only varieties. The first part closes with a review of the criteria physical and mental, used in determining race. Of the physical the most valuable are the shape of the skull, the facial and nasal indices and the hair. There is today no pure race. The four or five divisions usually recognized and called races are all more or less mixed. Just as there are peoples belonging to the White, Caucasian or Eurafrican race who are almost black, so there are men of a light brown or yellow color who belong to the Black, Ethiopian or Austafrican race. Racial divisions are based not on any one character but on many taken together. But men differ not merely physically. There are mental differences as well. Language is the "chief mental criterion." Here we are on uncertain ground. Uncertain however only when we forget with what readiness people may change and often have changed their speech. Difference of language does not mean necessarily difference of race. Language often tells us something of a people's history, of its conflicts and collisions with other peoples, but often fails to tell us anything of racial connections. The author does not lose sight of this fact. He gives many instances to illustrate the adoption of a new tongue. There are the Cornish and a large part of the Irish, Keltic peoples both, now speaking a Teutonic tongue; the French people, in part Kelts, in part Teutons, in part too, perhaps, Iberians, speaking an Italic tongue. In the midst of this confusion in ethnology there is great need of clear, decisive statement. This we find in Mr. Keane's book.
The second part of the work, that devoted to primary ethnical groups, which may be more properly called ethnology, is valuable as a concise statement of the afTmities of the peoples of the world today and a discussion of some important questions. But we do not find it so much to be commended as the first part. The Hominidæ are divided into four primary groups: Homo-Æthiopicus, Mongolicus,
