During this period of two centuries of colonization the European races
have attempted to perpetuate their families upon these lands in question.
They brought with them strong physical forces, and a high degree of mental
cultivation. Mental strength will endure extremes of climate to a singular
degree, but even this gradually yields to cosmic influences. It is a
well-observed law of Nature that man must be organized in harmony with the
condition of climate, otherwise he perishes. This scale of the strength of
resisting opposing forces depends greatly upon the purity of the blood and
the cultivation of the mind, whose remarkable powers of resisting disease
have been observed and pointed out by Malte-Brun, Goethe, Kant, and other
philosophers.
Europeans may visit and remain for limited periods in almost every portion
of the globe. The deadly miasms of Central America, the pestilential
atmospheres of Central Africa, and the frozen mists of either pole, are
braved by the inquiring travellers of the civilized races, but not with
impunity.
Intelligent and educated men may live for a while as gentlemen of leisure,
in the midst of malarial climates, almost without perceptible effect, but
the moment they apply their forces to the cultivation of the earth, Nature
asserts her rights.
Yet during the period of the rich man, whilst he lives without physical
labor, in ease, contemplation, and contentment, degeneration is slowly but
surely taking place. The law of fecundity proves it, as with the Mamelukes
in Egypt, as observed by Volney.
The English race loses its energy, according to Farr, in two or three
generations in the lowlands of the West India Islands and in Southern
Asia. The Duke of Wellington believed that every English family in Lower
Bengal would die out in the third generation.