Influences of Geographic Environment - Ellen Churchill Semple (libby ebook reader .TXT) 📗
- Author: Ellen Churchill Semple
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Darwin holds that many slight changes in animals and plants, such as size, color, thickness of skin and hair, have been produced through food supply and climate from the external conditions under which the forms lived.37 Paul Ehrenreich, while regarding the chief race distinctions as permanent forms, not to be explained by external conditions, nevertheless concedes the slight and slow variation of the sub-race under changing conditions of food and climate as beyond doubt.38 Stature is partly a matter of feeding and hence of geographic condition. In mountain regions, where the food resources are scant, the varieties of wild animals are characterized by smaller size in general than are corresponding species in the lowlands. It is a noticeable fact that dwarfed horses or ponies have originated in islands, in Iceland, the Shetlands, Corsica and Sardinia. This is due either to scanty and unvaried food or to excessive inbreeding, or probably to both. The horses introduced into the Falkland Islands in 1764 have deteriorated so in size and strength in a few generations that they are in a fair way to develop a Falkland variety of pony.39 On the other hand, Mr. Homer Davenport states that the pure-bred Arabian horses raised on his New Jersey stock farm are in the third generation a hand higher than their grandsires imported from Arabia, and of more angular build. The result is due to more abundant and nutritious food and the elimination of long desert journeys.
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.
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 Fuego46 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.
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.
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
The Indians of South America, though all fundamentally of the same ethnic stock, are variously acclimated to the warm, damp, forested plains of the Amazon; to the hot, dry, treeless coasts of Peru; and to the cold, arid heights of the Andes. The habitat that bred them tends to hold them, by restricting the range of climate which they can endure. In the zone of the Andean slope lying between 4,000 and 6,000 feet of altitude, which produces the best flavored coffee and which must be cultivated, the imported Indians from the high plateaus and from the low Amazon plains alike sicken and die after a short time; so that they take employment on these coffee plantations for only three or five months, and then return to their own homes. Labor becomes nomadic on these slopes, and in the intervals these farm lands of intensive agriculture show the anomaly of a sparse population only of resident managers.51 Similarly in the high, dry Himalayan valley of the upper Indus, over 10,000 feet above sea level, the natives of Ladak are restricted to a habitat that yields them little margin of food for natural growth of population but forbids them to emigrate in search of more,—applies at the same time the lash to drive and the leash to hold, for these highlanders soon die when they reach the plains.52 Here are two antagonistic geographic influences at work from the same environment, one physical and the other social-economic. The Ladaki have reached an interesting resolution of these two forces by the institution of polyandry, which keeps population practically stationary.
The relation of pigmentation to climate has long interested geographers as a question of environment; but their speculations on the subject have been barren, because the preliminary investigations of the physiologist, physicist and chemist are still incomplete. The general fact of increasing nigrescence from temperate towards equatorial regions is conspicuous enough, despite some irregularity of the shading.53 This fact points strongly to some direct relation between climate and pigmentation, but gives no hint how the pigmental processes are affected. The physiologist finds that in the case of the negro, the dark skin is associated with a dense cuticle, diminished perspiration, smaller chests and less respiratory power, a lower temperature and more rapid pulse,54 all which variations may enter into the problem of the negroes coloring. The question is therefore by no means simple.
Yet it is generally conceded by scientists that pigment is a protective device of nature. The negro's skin is comparatively insensitive to a sun heat that blisters a white man. Livingstone found the bodies of albino negroes in Bechuana Land always blistered on exposure to the sun,55 and a like effect has been observed among albino Polynesians, and Melanesians of Fiji.56 Paul Ehrenreich finds that the degree of coloration depends less upon annual temperature than upon the direct effect of the sun's rays; and that therefore a people dwelling in a cool, dry climate, but exposed to the sun may be darker than another in a hot, moist climate but living in a dense forest. The forest-dwelling Botokudos of the upper San Francisco River in Brazil are fairer than the kindred Kayapo tribe, who inhabit the open campos; and the Arawak of the Purus River forests are lighter than their fellows in the central Matto Grosso.57 Sea-faring coast folk, who are constantly exposed to the sun, especially in the Tropics, show a deeper pigmentation than their kindred of the wooded interior.58 The coast Moros of western Mindanao are darker than the Subanos, their Malay brethren of the back country, the lightness of whose color can be explained by their forest life.59 So the Duallas of the Kamerun coast of Africa are darker than the Bakwiri inhabiting the forested mountains just behind them, though both tribes belong to the Bantu group of people.60 Here light, in contradistinction to heat, appears the dominant factor in pigmentation. A recent theory, advanced by von Schmaedel in 1895, rests upon the chemical power of light. It holds that the black pigment renders the negro skin insensitive to the luminous or actinic effects of solar radiation, which are far more destructive to living protoplasm than the merely calorific effects.61
Coloration responds to other more obscure influences of environment. A close connection between pigmentation and elevation above sea level has been established: a high altitude operates like a high latitude. Blondness increases appreciably on the higher slopes of the Black
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