there is room for much doubt as to the cooperation of this principle in
evolution. Not only is it difficult to imagine how the transmission of
functional modifications could take place, but, up to the present time,
notwithstanding the endeavours of many excellent investigators, not
a single actual proof of such inheritance has been brought forward.
Semon's experiments on plants are, according to the botanist Pfeffer,
not to be relied on, and even the recent, beautiful experiments made
by Dr Kammerer on salamanders, cannot, as I hope to show elsewhere,
be regarded as proof, if only because they do not deal at all with
functional modifications, that is, with modifications brought about by
use, and it is to these ALONE that the Lamarckian principle refers.

III. OBJECTIONS TO THE THEORY OF SELECTION.

(a) Saltatory evolution.

The Darwinian doctrine of evolution depends essentially on THE
CUMULATIVE AUGMENTATION of minute variations in the direction of
utility. But can such minute variations, which are undoubtedly
continually appearing among the individuals of the same species,
possess any selection-value; can they determine which individuals are
to survive, and which are to succumb; can they be increased by natural
selection till they attain to the highest development of a purposive
variation?

To many this seems so improbable that they have urged a theory of
evolution by leaps from species to species. Kolliker, in 1872, compared
the evolution of species with the processes which we can observe in the
individual life in cases of alternation of generations. But a polyp only
gives rise to a medusa because it has itself arisen from one, and there
can be no question of a medusa ever having arisen suddenly and de
novo from a polyp-bud, if only because both forms are adapted in their
structure as a whole, and in every detail to the conditions of their
life. A sudden origin, in a natural way, of numerous adaptations is
inconceivable. Even the degeneration of a medusoid from a free-swimming
animal to a mere brood-sac (gonophore) is not sudden and saltatory, but
occurs by imperceptible modifications throughout hundreds of years, as
we can learn from the numerous stages of the process of degeneration
persisting at the same time in different species.

If, then, the degeneration to a simple brood-sac takes place only by
very slow transitions, each stage of which may last for centuries, how
could the much more complex ASCENDING