denotes as the continuity of the germ plasm ; and he
chooses the latter alternative as the basis of his theory.
This theory is supposed to afford a great support to
the doctrine of Pure Darwinism ; and it does this by
assuming that the only modification which this continuous
germ plasm undergoes is due to sexual reproduction
through the union of the sexual elements of two indi
viduals. Dr. Weismann says :—
“ I regard this combination as the cause of hereditary individual
characters, and I believe that the production of such characters is
the true significance of amphigonic (sexual) reproduction. The
object of this process is to create those individual differences which
form the material out of which Natural Selection produces new
species.”—{Essays upon Heredity, ist ed., vol. i., p. 272.)
Mr. Osborn regards Dr. Weismann’s theory as supporting
the theory of Pure Darwinism. He says :—
“ This (theory of the continuity of the germ plasm) does not
seem to be necessarily antagonistic to the Lamarckian idea, for we
can conceive that the germ plasm is continuous and still influenced
in definite ways by the body which contains it. Yet Weismann
holds that this is not the case ; that no special or local life-changes
in the body can in any way reach or influence the germ cells in
such a manner as to be inherited. This view throws the whole
burden of evolution upon the Natural Selection or survival of those
individuals which possess, by blending or otherwise, that germ plasm
which represents the bodily constitution and structure best fitted to
environment.”—(Henry Fairfield Osborn. Evolution and Heredity.
Apud Biological Lectures, delivered at Wood's Holl, 1890. p. 239.)
Mr. Romanes takes the same view as to the significancy
of the theory of the continuity of the germ plasm.
“Now it is evident that, according to this theory, Natural Selec
tion is constituted the one and only cause of organic evolution ;
and for this reason, the followers of Weismann are in the habit of
calling his doctrine ‘ Pure Darwinism,’ inasmuch as, without invoking
any aid from the Lamarckian principles above described, it con
stitutes the Darwinian principle of Natural Selection the sole, and
not merely as he said the ‘ main,’ means of modification.”—(Con
temporary Review, vol. Ivi., p. 248.)