irchow's maxim:--"The plan of
organisation is immutable within the limits of the species; species is
not produced from species." The fundamental teleological idea of that
school, that each species has its constant and specific plan of
structure, certainly cannot be more emphatically expressed. Thus it is
undoubtedly certain that Virchow has become a Dualist, and is as
thoroughly penetrated by the truth of his principles as I, as a
Monist, am of mine. This is undoubtedly the upshot of his Munich
address, though he is throughout careful to avoid acknowledging his
chief standpoint in all its nakedness. On the contrary, even now he
still veils his antagonism under the phrase, which is also a favourite
with the clerical papers, that the theory of descent is an "unproved
hypothesis." Now it is clear that this theory never will be "proved"
if the proofs that already lie before us are not sufficient. How often
has it been repeated that the scientific certainty of the hypothesis
of descent is not grounded in this or that isolated experiment, but in
the collective sum of biological phenomena; in the causal nexus of
evolution. Then what are the new proofs of the theory of descent which
Virchow demands of us?

FOOTNOTES:

[10] "Wirkliche Geheime Ober-Confusionsrath."

[11] Translated under the supervision of E. Ray Lankester. London: C.
Kegan Paul & Co.

CHAPTER II.

CERTAIN PROOFS OF THE DOCTRINE OF DESCENT.

All the common phenomena of Morphology and Physiology, of Chorology
and Oekology, of Ontology and Paleontology, can be explained by the
theory of descent, and referred to simple mechanical causes. It is
precisely in this, viz., that the primary simple causes of all these
complex aggregates of phenomena are common to them all, and that other
mechanical causes for them are unthinkable--it is in this that, to us,
the guarantee of their certainty consists. For this reason all these
vast and manifold aggregates of facts are so many evidences of the
doctrine of descent. This fundamental relation of facts has been so
often expounded that I need dwell no farther on it in this place;
those who wish for any closer discussion of it are referred to my
"General Morphology" (vol. ii. chap. xix.), or "The History of
Creation,"[12] or "The Evolution of Man" (vol. i. p. 93).[13]

And where is yet farther proof of the truth of the theory of descent
to be found? Neither Virchow, nor any one of the clerical opponents
and the