trifling, as well as of the most important characters in man, than in any
of the lower animals; though the facts are copious enough with respect to
the latter. So in regard to mental qualities, their transmission is
manifest in our dogs, horses, and other domestic animals. Besides special
tastes and habits, general intelligence, courage, bad and good temper,
etc., are certainly transmitted. With man we see similar facts in almost
every family; and we now know, through the admirable labours of Mr. Galton
(10. 'Hereditary Genius: an Inquiry into its Laws and Consequences,'
1869.), that genius which implies a wonderfully complex combination of high
faculties, tends to be inherited; and, on the other hand, it is too certain
that insanity and deteriorated mental powers likewise run in families.

With respect to the causes of variability, we are in all cases very
ignorant; but we can see that in man as in the lower animals, they stand in
some relation to the conditions to which each species has been exposed,
during several generations. Domesticated animals vary more than those in a
state of nature; and this is apparently due to the diversified and changing
nature of the conditions to which they have been subjected. In this
respect the different races of man resemble domesticated animals, and so do
the individuals of the same race, when inhabiting a very wide area, like
that of America. We see the influence of diversified conditions in the
more civilised nations; for the members belonging to different grades of
rank, and following different occupations, present a greater range of
character than do the members of barbarous nations. But the uniformity of
savages has often been exaggerated, and in some cases can hardly be said to
exist. (11. Mr. Bates remarks ('The Naturalist on the Amazons,' 1863,
vol. ii p. 159), with respect to the Indians of the same South American
tribe, "no two of them were at all similar in the shape of the head; one
man had an oval visage with fine features, and another was quite Mongolian
in breadth and prominence of cheek, spread of nostrils, and obliquity of