of the seed; the pollen or farina of one flower is thrown upon the pistil
of another, and the crossing of varieties of plants so essential to the
perfection of the vegetable world produced. In man moral causes and
physical ones modify each other; the transmission of hereditary qualities
to offspring is distinct in the animal world, and in the case of
disposition to disease it is sufficiently obvious in the human being. But
it is likewise a general principle that powers or habits acquired by
cultivation are transmitted to the next generation and exalted or
perpetuated; the history of particular races of men affords distinct
proofs of this. The Caucasian stock has always preserved its
superiority, whilst the negro or flat-nosed race has always been marked
for want of intellectual power and capacity for the arts of life. This
last race, in fact, has never been cultivated, and a hundred generations,
successively improved, would be required to bring it to the state in
which the Caucasian race was at the time of the formation of the Greek
republics. The principle of the improvement of the character of races by
the transmission of hereditary qualities has not escaped the observations
of the legislators of the ancient people. By the divine law of Moses the
Israelites were enjoined to preserve the purity of their blood, and there
was no higher crime than that of forming alliances with the idolatrous
nations surrounding them. The Brahmins of Hindostan have established
upon the same principle the law of caste, by which certain professions
were made hereditary. In this warm climate, where labour is so
oppressive, to secure perfection in any series of operations it seems
essential to strengthen the powers by the forces acquired from this
principle of hereditary descent. It will at first perhaps strike your
mind that the mixing or blending of races is in direct opposition to this
principle of perfection; but here I must require you to pause and
consider the nature of the qualities belonging to the human being. Excess
of a particular power, which in itself is a perfection, becomes a defect;