Such conclusions must, in last analysis, rest upon a satisfactory classification of mankind as a whole, but as stated at the outset, this has proved a difficult problem, and the reader will find the literature of the subject very perplexing, each investigator proposing a different scheme. Upon analysis, however, we find these schemes have a great deal in common and, hence, are fairly intelligible. In the first place, they fall into two groups according to the controlling concepts. One of these classifications is purely objective and empirical, no regard being paid to ancestral relations or other related factors, while in the other, the ideal is to form a classificatory scheme that will express genetic relationships. The exposition of these systems does not fall within the scope of this work, but a few of their main features may be noted.
Taking men as they come, experience shows that the most definitive objective characters are hair, skin color, and head form. Of these, the first is most persistently transmitted from parent to offspring, and so tends to remain constant. In the main, three kinds of hair are recognized: straight, wavy, and woolly, each having a distinctive cross-section and associated peculiarities.[1] With these as the points of departure, the people of the world fall into three groups:—
1. Straight hair (leiotrichi). The Asian-American group.
2. Wavy hair (cymotrichi). The Polynesian-European group.
3. Woolly hair (ulotrichi). The Australian-African group.
It is important to note that, though this grouping is strictly based upon the hair, the majority of all classifications recognize these three great clusters of mankind, their differences
