lizabeth Bickford. In many
species there are twelve ovarian tubes, and they decrease from that
number to one; indeed, in one species no ovarian tube at all is present.
So much at least is certain from what has been said, that in this
case EVERYTHING depends on the fluctuations of the elements of the
germ-plasm. Germinal selection, here as elsewhere, presents the
variations of the determinants, and personal selection favours or
rejects these, or,--if it be a question of organs which have become
useless,--it does not come into play at all, and allows the descending
variation free course.

It is obvious that even the problem of COADAPTATION IN STERILE
ANIMALS can thus be satisfactorily explained. If the determinants are
oscillating upwards and downwards in continual fluctuation, and
varying more pronouncedly now in one direction now in the other, useful
variations of every determinant will continually present themselves
anew, and may, in the course of generations, be combined with one
another in various ways. But there is one character of the determinants
that greatly facilitates this complex process of selection, that,
after a certain limit has been reached, they go on varying in the same
direction. From this it follows that development along a path once
struck out may proceed without the continual intervention of personal
selection. This factor only operates, so to speak, at the beginning,
when it selects the determinants which are varying in the right
direction, and again at the end, when it is necessary to put a check
upon further variation. In addition to this, enormously long periods
have been available for all these adaptations, as the very gradual
transition stages between females and workers in many species plainly
show, and thus this process of transformation loses the marvellous and
mysterious character that seemed at the first glance to invest it,
and takes rank, without any straining, among the other processes of
selection. It seems to me that, from the facts that sterile animal forms
can adapt themselves to new vital functions, their superfluous parts
degenerate, and the parts more used adapt themselves in an ascending
direction, those less used in a descending direction, we must draw
the conclusion that harmonious adaptation here comes about WITHOUT
THE COOPERATION OF THE LAMARCKIAN PRINCIPLE. This conclusion once
established, however, we have no reason to refer the thousands of cases
of harmonious adaptati