itions of
one species into another, which he asks to see, abound on all sides,
as is well known to every systematic naturalist. Only consider, for
example, the genera of Rubus and Salix among the living plants of the
present period, and the Ammonites and Brachiopoda among extinct
animals. Hence, too, Virchow can have no independent views as to the
historical development of the higher from the lower animals, because
the abundant living forms of the lower animals are almost unknown to
him, and because he has hardly any conception of the marvellous
strides which hundreds of industrious workers have made in this very
department within the last twenty years. But there can be no doubt,
indeed it is already universally acknowledged, that it is precisely
the comparative anatomy of the lower--nay, of the very lowest
animals--that has solved the greatest riddles of life, and removed the
greatest obstacles from the path of the doctrine of descent. He simply
ignores the fact that true Monads actually exist, and have been
positively identified by many different observers as structureless
"organisms without organs," and he turns out the poor Bathybius with a
kick. And yet I believe that in "Kosmos"[15] I have conclusively proved
that Monads must retain their vast elementary importance whether the
Bathybius actually exists or not.

But even as regards the higher animals--nay, even as to the
comparative anatomy of the highest next to man, the apes--Virchow
stands apart, not understanding the views of modern morphology.

We must here examine more closely into this, because it is precisely
in this department that Virchow's only morphological experiments have
been made; viz., his investigations as to the skulls of apes and of
men. This is precisely the one only point on which he has sought a
closer acquaintance with morphology, and precisely here it is most
clearly to be seen how little he is acquainted with the recent
advances our science has made, and that he has hardly any conception
of the extraordinary importance to that science of the theory of
descent.

The skull theory, as is well known, has for a long time been a very
favourite theme, not only with prominent naturalists, but also with
talented amateurs. Undoubtedly the skull, viewed as the bony capsule
which encloses our most important organ of sense, our brain, has a
special claim to morphological importance; for the general
conformation of the skull corresponds on the whole