le
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. Koelliker, 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_ evolution possibly have taken
place by sudden lea