The Descent of Man

acters of the adults must have been acquired
late in life; nevertheless, these characters, in
apparent contradiction to our rule, are transferred
to both sexes. We must not however, overlook
the possibility or even probability of successive
variations of the same nature occurring,
under exposure to similar conditions, simultaneously
in both sexes at a rather late period of
life; and in this case the variations would be
transferred to the offspring of both sexes at a
corresponding late age; and there would then
be no real contradiction to the rule that variations
occurring late in life are transferred exclusively
to the sex in which they first appeared.
This latter rule seems to hold true more generally
than the second one, namely, that variations
which occur in either sex early in life tend to be
transferred to both sexes. As it was obviously
impossible even to estimate in how large a
number of cases throughout the animal kingdom
these two propositions held good, it occu-