"If Darwin is right, it must be demonstrated that forms may be produced
by selection, which, like the present sharply distinguished animal
forms, are infertile, when coupled with one another, and this has not
been done."

The weight of this objection is obvious; but our ignorance of the
conditions of fertility and sterility, the want of carefully conducted
experiments extending over long series of years, and the strange
anomalies presented by the results of the cross-fertilization of many
plants, should all, as Mr. Darwin has urged, be taken into account in
considering it.

The seventh objection is that we have already discussed ('supra', p.
178).

The eighth and last stands as follows:--

"8. The developmental theory of Darwin is not needed to enable us to
understand the regular harmonious progress of the complete series of
organic forms from the simpler to the more perfect.

"The existence of general laws of Nature explains this harmony, even if
we assume that all beings have arisen separately and independent of one
another. Darwin forgets that inorganic nature, in which there can be no
thought of genetic connexion of forms, exhibits the same regular plan,
the same harmony, as the organic world; and that, to cite only one
example, there is as much a natural system of minerals as of plants and
animals."