character which has long been transmitted true or unaltered still being
transmitted true as long as the conditions of life remain the same. We know
that many species, after having retained the same character for countless
ages, whilst living under their natural conditions, when domesticated have
varied in the most diversified manner, that is, have failed to transmit their
original form; so that no character appears to be absolutely fixed. We can
sometimes account for the failure of inheritance by the conditions of life
being opposed to the development of certain characters; and still oftener, as
with plants cultivated by grafts and buds, by the conditions causing new and
slight modifications incessantly to appear. In this latter case it is not that
inheritance wholly fails, but that new characters are continually superadded.
In some few cases, in which both parents are similarly characterised,
inheritance seems to gain so much force by the combined action of the two
parents, that it counteracts its own power, and a new modification is the
result.

In many cases the failure of the parents to transmit their likeness is due to
the breed having been at some former period crossed; and the child takes after
his grandparent or more remote ancestor of foreign blood. In other cases, in
which the breed has not been crossed, but some ancient character has been lost
through variation, it occasionally reappears through reversion, so that the
parents apparently fail to transmit their own likeness. In all cases, however,
we may safely conclude that the child inherits all its characters from its
parents, in whom certain characters are latent, like the secondary sexual
characters of one sex in the other. When, after a long succession of bud-
generations, a flower or fruit becomes separated into distinct segments,
having the colours or other attributes of both parent-forms, we cannot doubt
that these characters were latent in the earlier buds, though they could not
then be detected, or could be detected only in an intimately commingled state.
So it is with animals of crossed parentage, which with advancing years