e and living sciences--these must
not be taught at all. And how then do matters stand with regard to the
cell-theory, that fundamental theory on which every element of our
morphology and physiology depends, and by applying which Virchow
himself reached his grandest results?

Since Schleiden in Jena, forty years ago, first put forward the
cell-theory, and Schwann immediately after applied it to the animal
kingdom and so to the whole organic world, this fundamental doctrine
has undergone very important modifications, for it is indeed a
biological theory, but not a fact. We may recollect under what
different aspects its main principles have appeared in the course of
these four decades: what changes have taken place in the conception of
the cell itself. After the organic cell had originally been conceived
of as a vesicle, consisting of a firm capsule and a fluid content, we
subsequently discerned it to be composed of a glutinous semi-fluid
cell-substance, the protoplasm, and convinced ourselves that this
protoplasm and the cell-core or nucleus enclosed in it are the most
important and indispensable constituent parts of the cell, while the
external firm capsule, the cell-membrane, is not essential and very
frequently wanting. But even now opinions widely differ as to how the
conception of a cell should be precisely defined, and what
consequences must be inferred from the cell-theory, and attempts have
not been wanting to upset it altogether and to treat it as worthless.
The anatomist Henle, of Goettingen, in particular, has repeatedly made
such an attempt, that "gifted" anatomist who, in the preface to his
bulky text-book of human anatomy, declared that scientific ideas are
mere worthless paper money, and that the noble metal of facts, on the
contrary, is the only genuine article. Not long since a bulky volume
in quarto appeared, by one Herr Nathusius-Koenigsborn, in which the
cell is explained to be a subordinate plastic element, and the
cell-theory is eliminated as superfluous; and this monstrous volume,
full of the most amusing nonsense, is dedicated to Herr Henle. Virchow
formerly was one of the victorious opponents of the Goettingen
physician, and wrote brilliant articles against the "rational
pathology" of "irrational Herr Henle;" now apparently he agrees with
him that the paper money of ideas is worthless as compared with the
noble metal of facts. Of course the cell-theory then loses all its
value, and cannot be a su