special
endowment,
beyond the
province
of our
reasoning
powers.
The
fertility
of
varieties,
that is of
the forms
known or
believed
to have
descended
from
common
parents,
when
intercrossed,
and
likewise
the
fertility
of their
mongrel
offspring,
is, on my
theory, of
equal
importance
with the
sterility
of
species;
for it
seems to
make a
broad and
clear
distinction
between
varieties
and
species.
First, for
the
sterility
