22 The Selection Theory 
addition to other factors, he laid special emphasis on the increased 
or diminished use of the parts of the body, assuming that the 
strengthening or weakening which takes place from this cause 
during the individual life, could be handed on to the offspring, and 
thus intensified and raised to the rank of a specific character. 
Darwin also regarded this Lamarckian principle, as it is now 
generally called, as a factor in evolution, but he was not fully con- 
vinced of the transmissibility of acquired characters. 
As I have here to deal only with the theory of selection, I need 
not discuss the Lamarckian hypothesis, but I must express my opinion 
that 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. Killiker, 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 
