ent literature of zoology and
botany! Our whole morphological literature in particular is already so
deeply and completely penetrated by the doctrine of descent,
phylogenetic principles already prevail so universally as a certain
and indispensable instrument of inquiry, that no man for the future
would deprive himself of their help. As Oscar Schmidt justly
observes--"Perhaps ninety-nine per cent. of all living, or rather of
all working zoologists, are convinced by inductive methods of the
truth of the doctrine of descent." And Virchow with his magisterial
requirements will attain only the very reverse of what he aims at. How
often has it not been said already that science must either have
perfect freedom or else none at all? This is as true of teaching as
it is of inquiry, for the two are intrinsically and inseparably
connected. And so it is not in vain that it is written in section 152
of the German Code, and in section 20 of the Prussian Charter,
"Science and her teaching shall be free!"

CHAPTER VI.

THE DOCTRINE OF DESCENT AND SOCIAL DEMOCRACY.

Every great and comprehensive theory which affects the foundations of
human science, and which, consequently, influences the systems of
philosophy, will, in the first place, not only further our theoretical
views of the universe, but will also react on practical philosophy,
ethics, and the correlated provinces of religion and politics. In my
paper read at Munich I only briefly pointed out the happy results
which, in my opinion, the modern doctrine of evolution will entail
when the true, natural religion, founded on reason, takes the place of
the dogmatic religion of the Church, and its leading principle derives
the human sense of duty from the social instincts of animals.

The references to the social instincts which I, in common with Darwin
and many others, regard as the proper source and origin of all moral
development, appear to have afforded Virchow an opportunity in his
reply for designating the doctrine of inheritance as a "socialist
theory," and for attributing to it the most dangerous and
objectionable character which, at the present time, any political
theory can have; and these startling denunciations so soon as they
were known called forth such just indignation and such comprehensive
refutation that I might very properly pass them over here. Still we
must at least shortly examine them, in so far as they supply a further
proof that Virchow is unacquain