h the rest of mankind.

For the source of any characteristic so widespread and uniform as this
adaptation to environment we must go back to the very beginning of the
human race. Such a characteristic must have become firmly fixed in the
human constitution before primitive man became divided into races, or at
least before any of the races had left their original home and started
on their long journey to America. On the way to this continent one race
took on a dark reddish or brownish hue and its hair grew straight and
black; another became black skinned and crinkly-haired, while a
third developed a white skin and wavy blonde hair. Yet throughout the
thousands of years which brought about these changes, all the races
apparently retained the indelible constitutional impress of the climate
of their common birthplace. Man's physical adaptation to climate seems
to be a deep-seated physiological fact like the uniformity of the
temperature of the blood in all races. Just as a change in the
temperature of the blood brings distress to the individual, so a change
of climate apparently brings distress to a race. Again and again, to be
sure, on the way to America, and under many other circumstances, man has
passed through the most adverse climates and has survived, but he has
flourished and waxed strong only in certain zones.

Curiously enough man's body and his mind appear to differ in their
climatic adaptations. Moreover, in this respect the black race, and
perhaps the red, appears to be diverse from the white. In America an
investigation of the marks of students at West Point and Annapolis
indicates that the best mental work is done when the temperature
averages not much above 40 degrees F. for night and day together. Tests
of school children in Denmark point to a similar conclusion. On the
other hand, daily tests of twenty-two Negroes at Hampton Institute for
sixteen months suggest that their mental ability may be greatest at a
temperature only a little lower than that which is best for the most
efficient physical activity. No tests of this sort have ever been made
upon Indians, but such facts as the inventiveness of the Eskimo, the
artistic development of the people of northern British Columbia and
southern Alaska, and the relatively high civilization of the cold
regions of the Peruvian plateau suggest that the Indian in this respect
is more like the white race than the black. Perhaps man's mental powers
underwent their chief