cultivated
plants the transference of characters may be accomplished and may
occur by _integral steps_ [italics ours], until one species is
definitely 'transformed' into the other."

Needless to say, this is quite different from the gradual
transformation of species that Darwinism or Lamarckism assumes to take
place. One species becomes another _per saltum_ in virtue of some
special energy infused into it, some original tendency of its
intrinsic nature, not because of gradual modification by forces
outside of the organisms, nor because of the combination of influences
they are subjected to from without and within, because of tendency to
evolute plus {218} environmental forces. This throws biology back to
the permanency of species in themselves, though successive generations
may be of different species, and does away with the idea of missing
links, since there are no gradual connecting gradations.

A very interesting phase of Mendel's discoveries is concerned with the
relative value of the egg-cell and the pollen-cell, as regards their
effect upon future generations. It is an old and oft-discussed problem
as to which of these germinal particles is the more important in its
influence upon the transmission of parental qualities. Mendel's
observations would seem to decide definitely that, in plants and, by
implication, in animals, since the germinal process is biogenetically
similar, the value of both germinal particles is exactly equal.

In a note, Mendel says:--

_In pisum_ (i. e. in peas), it is beyond doubt that, for the
formation of the new embryo, a perfect union of the elements of both
fertilizing cells must take place. How could we otherwise explain
that, among the offspring of the hybrids, both original types
reappear in equal numbers, and with all their peculiarities? If the
influence of the egg-cell upon the pollen-cell were only external,
if it fulfilled the role of a nurse only, then the result of each
artificial fertilization could be no other than that the developed
hybrid should exactly resemble the pollen parent, or, at any rate,
do so very closely. These experiments, so far, have in no wise been
confirmed. An evident proof of the complete union of the contents of
both cells is afforded by the {219} experience gained on all sides,
that it is immaterial as regards the form of the hybrid which of the
original species is the seed cell, or which the pollen parent!

This is the