As within these wide limits of time we can reply to the question when the races became such, so within similar broad boundaries of space we can answer where their peculiar types were developed.
At the dawn of history, all the clearly marked sub-species of man bore distinct relations in number and distribution to the great continental areas into which the habitable land of the globe is divided. Nearly the whole of Europe and its geographical appendix, North Africa, were in the possession of the white race; the true negro type was limited to Central and Southern Africa and its appended islands; the yellow or Mongolian type was scarcely found outside of Asia; and the American sub-species was absolutely confined to that continent.
_The “Areas of Characterization.”_--In claiming that each sub-species had its origin and developed its physical peculiarities in the land areas here assigned to it, the ethnographer is supported by the unanimous verdict of modern zoölogical science. “Whatever be the cause,” writes the Rev. Samuel Haughton, “the distribution of fauna shows clearly that forces have been at work, developing in each great continent animal forms peculiar to itself, and differing from the animal forms developed by other continents.”[47]
In ethnography, those geographical areas whose physical conditions have left a durable impress on their human inhabitants have been called either “geographical provinces” (Bastian) or “areas of characterization” (de Quatrefages). I prefer and shall adopt the latter as more indicative of the meaning of the term. It signifies that like physio-geographical conditions prevailing over a given area inhabited for many generations by the same peoples have impressed upon them certain traits, physical and psychical, which have become hereditary and continue indeterminately, even under changed conditions of existence.
This general law is the recognized basis of modern scientific ethnography.[48] It is open to numerous limitations, and its application must never be made without the consideration of accessory and modifying circumstances. For instance, certain areas are much more potent than others in the influence they exert on man: some act more powerfully on his mind than on his body, or the reverse; some peoples are more susceptible to physical influences of a given class than others; and the length of time required is variable.