nment of stationary plants and animals, whose range of movement is
strictly determined by conditions of food and temperature, the great
mobility of man, combined with his inventiveness, enables him to flee or
seek almost any climatic condition, and to emancipate himself from the
full tyranny of climatic control by substituting an indirect economic
effect for a direct physical effect.

The direct results of climate are various, though some are open to the
charge of imperfect proof. Even the relation of nigrescence to tropical
heat, which seems to be established by the geographical distribution of
negroid races in the Old World, fails to find support from the facts of
pigmentation among the American Indians from Alaska to Tierra del Fuego.
Nevertheless climate undoubtedly modifies many physiological processes
in individuals and peoples,[1411] affects their immunity from certain
classes of diseases and their susceptibility to others, influences their
temperament, their energy, their capacity for sustained or for merely
intermittent effort, and therefore helps determine their efficiency as
economic and political agents.

While producing these direct effects, climate also influences man
indirectly by controlling the wide range of his life conditions
dependent upon the plant and animal life about him. It dictates what
crops he may raise, and has it in its power to affect radically the size
of his harvest. It decides which flocks and herds are best suited to his
environment, and therefore directs his pastoral activities, whether he
keeps reindeer, camels, llamas, horses or horned cattle. By interdicting
both agriculture and stock-raising, as in Greenland whose ice cap leaves
little surface free even for reindeer moss, it condemns the inhabitants
forever to the uncertain subsistence of the hunter. Where it encourages
the growth of large forests which harbor abundant game and yield
abundant fruits, as in the hot, moist equatorial belt and on rainy
mountain slopes, it prolongs the hunter stage of development, retards
the advance to agriculture. Climate thus helps to influence the rate and
the limit of cultural development. It determines in part the local
supply of raw material with which man has to work, and hence the
majority of his secondary activities, except where these are expended on
mineral resources. It decides the character of his food, clothing, and
dwelling, and ultimately of his civilization.

[Sidenote: Effect of c