. Weismann
gave the impulse to these ideas in his theory on "Amphimixis".) In this
way all the cooperations which the carriers of hereditary characters are
capable of in a species are produced; this must give it an appreciable
advantage in the struggle for life.

The admirers of Charles Darwin must deeply regret that he did not live
to see the results achieved by the new Cytology. What service would they
have been to him in the presentation of his hypothesis of Pangenesis;
what an outlook into the future would they have given to his active
mind!

The Darwinian hypothesis of Pangenesis rests on the conception that all
inheritable properties are represented in the cells by small invisible
particles or gemmules and that these gemmules increase by division.
Cytology began to develop on new lines some years after the publication
in 1868 of Charles Darwin's "Provisional hypothesis of Pangenesis"
("Animals and Plants under Domestication", London, 1868, Chapter
XXVII.), and when he died in 1882 it was still in its infancy. Darwin
would have soon suggested the substitution of the nuclei for his
gemmules. At least the great majority of present-day investigators in
the domain of cytology have been led to the conclusion that the nucleus
is the carrier of hereditary characters, and they also believe that
hereditary characters are represented in the nucleus as distinct units.
Such would be Darwin's gemmules, which in conformity with the name
of his hypothesis may be called pangens (So called by H. de Vries in
1889.): these pangens multiply by division. All recently adopted
views may be thus linked on to this part of Darwin's hypothesis. It is
otherwise with Darwin's conception to which Pangenesis owes its name,
namely the view that all cells continually give off gemmules, which
migrate to other places in the organism, where they unite to form
reproductive cells. When Darwin foresaw this possibility, the continuity
of the germinal substance was still unknown (Demonstrated by Nussbaum in
1880, by Sachs in 1882, and by Weismann in 1885.), a fact which excludes
a transference of gemmules.

But even Charles Darwin's genius was confined within finite boundaries
by the state of science in his day.

It is not my province to deal with other theories of development which
followed from Darwin's Pangenesis, or to discuss their histological
probabilities. We can, however, affirm that Charles Darwin's idea that
invisible gemmules are the carr