The low stature of the natives prevailing in certain "misery spots" of Europe, as in the Auvergne Plateau of southern France, is due in part to race, in part to a disastrous artificial selection by the emigration of the taller and more robust individuals, but in considerable part to the harsh climate and starvation food-yield of that sterile soil; for the children of the region, if removed to the more fertile valleys of the Loire and Garonne, grow to average stature.[40] The effect of a scant and uncertain food supply is especially clear in savages, who have erected fewer buffers between themselves and the pressure of environment. The Bushmen of the Kalahari Desert are shorter than their Hottentot kindred who pasture their flocks and herds in the neighboring grasslands.[41] Samoyedes, Lapps, and other hyperborean races of Eurasia are shorter than their more southern neighbors, the physical record of an immemorial struggle against cold and hunger. The stunted forms and wretched aspect of the Snake Indians inhabiting the Rocky Mountain deserts distinguished these clans from the tall buffalo-hunting tribes of the plains.[42] Any feature of geographic environment tending to affect directly the physical vigor and strength of a people cannot fail to prove a potent factor in their history.
Physical effects of dominant activities.
Oftentimes environment modifies the physique of a people indirectly by imposing upon them certain predominant activities, which may develop one part of the body almost to the point of deformity. This is the effect of increased use or disuse which Darwin discusses. He attributes the thin legs and thick arms of the Payaguas Indians living along the Paraguay River to generations of lives spent in canoes, with the lower extremities motionless and the arm and chest muscles in constant exercise.[43] Livingstone found these same characteristics of broad chests and shoulders with ill-developed legs among the Barotse of the upper Zambesi;[44] and they have been observed in pronounced form, coupled with distinctly impaired powers of locomotion, among the Tlingit, Tsimshean, and Haida Indians of the southern Alaskan and British Columbia coast, where the geographic conditions of a mountainous and almost strandless shore interdicted agriculture and necessitated sea-faring activities.[45] An identical environment has produced a like physical effect upon the canoemen of Tierra del Fuego[46] and the Aleutian Islanders, who often sit in their boats twenty hours at a time.[47] These special adaptations are temporary in their nature and tend to disappear with change of occupation, as, for instance, among the Tlingit Indians, who develop improved leg muscles when employed as laborers in the salmon canneries of British Columbia.
Effects of climate.
Both the direct and indirect physical effects of environment thus far instanced are obvious in themselves and easily explained. Far different is it with the majority of physical effects, especially those of climate, whose mode of operation is much more obscure than was once supposed. The modern geographer does not indulge in the naive hypothesis of the last century, which assumed a prompt and direct effect of environment upon the form and features of man. Carl Ritter regarded the small, slit eyes and swollen lids of the Turkoman as "an obvious effect of the desert upon the organism." Stanhope Smith ascribed the high shoulders and short neck of the Tartars of Mongolia to their habit of raising their shoulders to protect the neck against the cold; their small, squinting eyes, overhanging brows, broad faces and high cheek bones, to the effect of the bitter, driving winds and the glare of the snow, till, he says, "every feature by the action of the cold is harsh and distorted."[48] These profound influences of a severe climate upon physiognomy he finds also among the Lapps, northern Mongolians, Samoyedes and Eskimo.
Acclimatization
Most of these problems are only secondarily grist for the geographer's mill. For instance, when the Aryans descended to the enervating lowlands of tropical India, and in that debilitating climate lost the qualities which first gave them supremacy, the change which they underwent was primarily a physiological one. It can be scientifically described and explained therefore only by physiologists and physico-chemists; and upon their investigations the geographer must wait before he approaches the problem from the standpoint of geographical distribution. Into this sub-class of physical effects come all questions of acclimatization.[49] These are important to the anthropo-geographer, just as they are to colonial governments like England or France, because they affect the power of national or racial expansion, and fix the historical fate of tropical lands. The present populations of the earth represent physical adaptation to their environments. The intense heat and humidity of most tropical lands prevent any permanent occupation by a native-born population of pure whites. The catarrhal zone north of the fortieth parallel in America soon exterminates the negroes.[50]