heory of Descent to explain this gradual perfection. The crude and
aimless activity of Darwinian selection, which necessarily operates
through "chance," can never explain this perfection, which remains, as
far as selection is concerned, one of the greatest enigmas of nature.
Far from solving the enigma, selection but makes it obscurer.

If, then, one refuses to recognize a directing creative Intelligence,
whose direction produces this perfection, nothing remains but Naegeli's
principle of perfection. The outer world with its influences can
certainly not produce perfection, hence this power must lie within the
organism itself. But when one has once brought himself to accept an
immanent principle of development, it surely cannot be difficult to
take the next step and ascribe to it the tendency towards perfection.

That Eimer does not take this step, is, to my mind, a mistake, which
must be attributed to his one-sidedness, which, in turn, results from
the fact that he generalizes too arbitrarily his observations on
butterflies and the conclusions which he draws from them. Animals and
plants certainly possess many characteristics which cannot be explained
by means of his theory alone. The conclusion will probably be finally
arrived at, that nature is inexhaustible and many-sided, even in the
lines on which it proceeds to attain this or that end.

One thing, however, of primary importance is evident from the
investigations of Eimer, namely the proof that the same lines of
development may be entered upon from entirely different
starting-points, and that the number of these lines is limited. This
fact is of importance because it enjoins more caution in arguing from
uniformity of development to family-relation, than has been usually
employed since the days of Darwin. The method commonly employed is
undoubtedly very convenient, but is somewhat liable to be misleading.
Hence, if one wishes to establish the genealogical relationship of
forms, nothing remains but to set out on the laborious path of studying
the development of both; and even then it remains questionable whether
the truth will be arrived at. However, he who concludes to relationship
from a comparison of developed forms, is much less likely to arrive at
the truth.

In one point Eimer concedes too much to Darwinism, in the matter of the
famous fundamental principle of biogenesis, according to which an
organism is said to repeat in its individual development the whol