bon, combined with the properties of oxygen,
hydrogen, nitrogen, etc., in certain proportions albumen should result,
is a process which in its essence is as incomprehensible as that a
living cell should arise from a certain organization of different
albumina." Then the speaker is inevitably led to speak of the doctrine
of Descent and Darwinism.

In the first place he declares definitely that ontogeny alone, i.e.,
the development of the individual being, is "capable of a direct
scientific investigation." On the other hand we move in the domain of
hypotheses in dealing with the further question: "How have the species
of organisms living to-day originated in the course of the world's
history?" This is a very valuable admission in view of Haeckel's
dogmatic assertion that the descent of man from the ape is a "certain
historical fact." Very moderate and pertinent are also the further
words of the speaker: "Of course, a philosophically trained
investigator will regard it as axiomatic that the organisms which
inhabit our earth to-day did not exist in their present form in earlier
periods of the earth and that they had to pass through a process of
development, beginning with the simplest forms."

"But in the attempt to outline in detail the particular form in which a
species of animals of our day existed in remote antiquity, we lose the
safe ground of experience. For out of the countless millions of
organisms, that lived in earlier periods of the earth, the duration of
which is measured by millions of years, only scanty skeleton remains
have by way of exception been preserved in a fossil state. From these
naturally but a very imperfect and hypothetical representation can be
formed of the soft bodies with which they were once clothed. And even
then it remains forever doubtful whether the progeny of the prehistoric
creature, the scant remains of which we study, has not become entirely
extinct, so that it can in no way be regarded as the progenitor of any
creature living at present." I should like to know wherein this differs
radically from Fleischmann's contention in his "Descendenztheorie" (p.
10.) For we find stated here what Fleischmann emphasizes so much, viz.,
that with the problem of Descent we leave the domain of experience. It
is worthy of special note in this connection that Hertwig likewise
evidently regards as the sole really empirically and inductively
serviceable proof of Descent, that which is drawn from palaeontol