be, a good expression. (13/47. 'Journal of Researches' 1845 page 71.)
Livingstone--and a more unimpeachable authority cannot be quoted,--after
speaking of a half-caste man on the Zambesi, described by the Portuguese as a
rare monster of inhumanity, remarks, "It is unaccountable why half-castes,
such as he, are so much more cruel than the Portuguese, but such is
undoubtedly the case." An inhabitant remarked to Livingstone, "God made white
men, and God made black men, but the Devil made halfcastes." (13/48.
'Expedition to the Zambesi' 1865 pages 25, 150.) When two races, both low in
the scale, are crossed the progeny seems to be eminently bad. Thus the noble-
hearted Humboldt, who felt no prejudice against the inferior races, speaks in
strong terms of the bad and savage disposition of Zambos, or half-castes
between Indians and Negroes; and this conclusion has been arrived at by
various observers. (13/49. Dr. P. Broca on 'Hybridity in the Genus Homo'
English translation 1864 page 39.) From these facts we may perhaps infer that
the degraded state of so many half-castes is in part due to reversion to a
primitive and savage condition, induced by the act of crossing, even if mainly
due to the unfavourable moral conditions under which they are generally
reared.

SUMMARY ON THE PROXIMATE CAUSES LEADING TO REVERSION.

When purely-bred animals or plants reassume long-lost characters,--when the
common ass, for instance, is born with striped legs, when a pure race of black
or white pigeons throws a slaty-blue bird, or when a cultivated heartsease
with large and rounded flowers produces a seedling with small and elongated
flowers,--we are quite unable to assign any proximate cause. When animals run
wild, the tendency to reversion, which, though it has been greatly
exaggerated, no doubt exists, is sometimes to a certain extent intelligible.
Thus, with feral pigs, exposure to the weather will probably favour the growth
of the bristles, as is known to be the case with the hair of other