their fertility, notwithstanding the frequent ill
effects from manipulation, sometimes decidedly increases, and goes on
increasing. Now, in the process of artificial fertilisation, pollen is
as often taken by chance (as I know from my own experience) from the
anthers of another flower, as from the anthers of the flower itself
which is to be fertilised; so that a cross between two flowers, though
probably often on the same plant, would be thus effected. Moreover,
whenever complicated experiments are in progress, so careful an observer
as Gartner would have castrated his hybrids, and this would have insured
in each generation a cross with pollen from a distinct flower, either
from the same plant or from another plant of the same hybrid nature.
And thus, the strange fact of an increase of fertility in the successive
generations of ARTIFICIALLY FERTILISED hybrids, in contrast with those
spontaneously self-fertilised, may, as I believe, be accounted for by
too close interbreeding having been avoided.

Now let us turn to the results arrived at by a third most experienced
hybridiser, namely, the Hon. and Rev. W. Herbert. He is as emphatic in
his conclusion that some hybrids are perfectly fertile--as fertile as
the pure parent-species--as are Kolreuter and Gartner that some degree
of sterility between distinct species is a universal law of nature.
He experimented on some of the very same species as did Gartner. The
difference in their results may, I think, be in part accounted for by
Herbert's great horticultural skill, and by his having hot-houses at his
command. Of his many important statements I will here give only a single
one as an example, namely, that "every ovule in a pod of Crinum capense
fertilised by C. revolutum produced a plant, which I never saw to occur
in a case of its natural fecundation." So that here we have perfect, or
even more than commonly perfect fertility, in a first cross between two
distinct species.

This case of the Crinum leads me to refer to a singular fact, namely,
that individual plants of certain species of Lobelia, Verbascum and
Passiflora, can easily be fertilised by the pollen from a distinct
species, but not by pollen from the same plant, though this pollen can
be proved to be perfectly sound by fertilising other plants or species.
In the genus Hippeastrum, in Corydalis as shown by Professor Hildebrand,
in various orchids as shown by Mr. Scott and Fritz Muller, all the
individuals are in