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.)