produced which is to be handed down.[35]
But environment determines what variation shall become stable enough to
be passed on by heredity. For instance, we can hardly err in attributing
the great lung capacity, massive chests, and abnormally large torsos of
the Quichua and Aymara Indians inhabiting the high Andean plateaus to
the rarified air found at an altitude of 10,000 or 15,000 feet above sea
level. Whether these have been acquired by centuries of extreme lung
expansion, or represent the survival of a chance variation of undoubted
advantage, they are a product of the environment. They are a serious
handicap when the Aymara Indian descends to the plains, where he either
dies off or leaves descendants with diminishing chests.[36] [See map page
101.]

[Sidenote: Stature and environment]

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 a