ls of the new organism are produced. There is,
therefore, continuity of the germ-plasm from one generation to
another. One might represent the germ-plasm by the metaphor of a
long creeping root-stock from which plants arise at intervals, these
latter representing the individuals of successive generations."
{274b}

Mr. Wallace, who does not appear to have read Professor Weismann's
essays themselves, but whose remarks are, no doubt, ultimately
derived from the sequel to the passage just quoted from page 266 of
Professor Weismann's book, contends that the impossibility of the
transmission of acquired characters follows as a logical result from
Professor Weismann's theory, inasmuch as the molecular structure of
the germ-plasm that will go to form any succeeding generation is
already predetermined within the still unformed embryo of its
predecessor; "and Weismann," continues Mr. Wallace, "holds that
there are no facts which really prove that acquired characters can
be inherited, although their inheritance has, by most writers, been
considered so probable as hardly to stand in need of direct proof."
{275}

Professor Weismann, in passages too numerous to quote, shows that he
recognizes this necessity, and acknowledges that the non-
transmission of acquired characters "forms the foundation of the
views" set forth in his book, p. 291.

Professor Ray Lankester does not commit himself absolutely to this
view, but lends it support by saying (Nature, December 12, 1889):
"It is hardly necessary to say that it has never yet been shown
experimentally that _anything_ acquired by one generation is
transmitted to the next (putting aside diseases)."

Mr. Romanes, writing in Nature, March 13, 1890, and opposing certain
details of Professor Weismann's theory, so far supports it as to say
that "there is the gravest possible doubt lying against the
supposition that any really inherited decrease is due to the
inherited effects of disuse." The "gravest possible doubt" should
mean that Mr. Romanes regards it as a moral certainty that disuse
has no transmitted effect in reducing an organ, and it should follow
that he holds use to have no transmitted effect in its development.
The sequel, however, makes me uncertain how far Mr. Romanes intends
this, and I would refer the reader to the article which Mr. Romanes
has just published on Weismann in the Contemporary Review for this
current month.

The burden of Mr. Thiselton Dyer's controversy