3. Physical Anthropology
The organic sciences underlie the social ones. They are more directly “natural.” Anthropology has therefore found valuable general principles in biology: laws of heredity, the doctrines of cell development and evolution, for instance, based on facts from the whole range of life. Its business has been to ascertain how far these principles apply to man, what forms they take in his particular case. This has meant a concentration of attention, the devising of special methods of inquiry. Many biological problems, including most physiological and hereditary ones, can be most profitably attacked in the laboratory, or at least under experimental conditions. This method, however, is but rarely open as regards human beings, who must ordinarily be observed as they are. The phenomena concerning man have to be taken as they come and laboriously sifted and re-sifted afterward, instead of being artificially simplified in advance, as by the experimental method. Then, too, since anthropology was operating within the narrow limits of one species, it was driven to concern itself with minute traits, such as the zoölogist is rarely troubled with: the proportions of the length and breadth of the skull—the famous cephalic index—for instance; the number of degrees the arm bones are twisted, and the like. Also, as these data had to be used in the gross, unmodifiable by artificially varied conditions, it has been necessary to secure them from all possible varieties of men, different races, sexes, ages, and their nearest brute analogues. The result is that biological or physical anthropology—“Somatology” it is sometimes called in Anglo-Saxon countries, and simply “anthropology” in continental Europe—has in part constituted a sort of specialization or sharpening of general biology, and has become absorbed to a considerable degree in certain particular phenomena and methods of studying them about which general biologists, physiologists, palæontologists, and students of medicine are usually but vaguely informed.