be fertilised during each generation by their own individual pollen; and I am convinced that this would be injurious to their fertility, already lessened by their hybrid origin.  I am strengthened in this conviction by a remarkable statement repeatedly made by Gartner, namely, that if even the less fertile hybrids be artificially fertilised with hybrid pollen of the same kind, their fertility, notwithstanding the frequent ill effects of manipulation, sometimes decidedly increases, and goes on increasing.  Now, in 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 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 the 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 the increase of fertility in the successive generations of artificially fertilised hybrids may, I believe, be accounted for by close interbreeding having been avoided.

Now let us turn to the results arrived at by the third most experienced hybridiser, namely, the Honourable and Reverend 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 experimentised 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 hothouses 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 (he says) I never saw to occur in a case of its natural fecundation.”  So that we here 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 most singular fact, namely, that there are individual plants, as with certain species of Lobelia, and with all the species of the genus Hippeastrum, which can be far more easily fertilised by the pollen of another and distinct species, than by their own pollen.  For these plants have been found to yield seed to the pollen of a distinct species, though quite sterile with their own pollen, notwithstanding that their own pollen was found to be perfectly good, for it fertilised distinct species.  So that certain individual plants and all the individuals of certain species can actually be hybridised much more readily than they can be self-fertilised!  For instance, a bulb