c world is not made up from branchings of a single original
idioplasm, but each race or group may have its own specific idioplasm;
and, since this has its own characteristic structure and its own
specific internal perfecting forces, it passes through its own peculiar
evolution, carrying with it its own depending race of organisms.

The fact that animals and plants at the present time show such various
degrees of organization is also accounted for on the last supposition,
for those of lowlier organization are merely of more recent origin and
have not progressed so far in idioplasmic development.

This automatic perfecting principle has been the mark of much criticism.
Some have confounded it with the mystical _nisus formativus_, or
formative principle of preceding theorists. But, as Weismann remarks,
Naegeli's phyletic force is conceived as a thoroughly scientific
mechanical principle. Naegeli has simply made application in the organic
world of the principle of entropy, as stated in the mechanical theory of
heat. Naegeli himself also compares his internal perfecting principle to
mechanical inertia. He says, "the force of evolution once started in a
given direction, tends to continue in the same direction. This
constitutes the law of inertia in the organic world."

* * * * *

Two other matters remain to be noticed. The first of these is Naegeli's
use of the German word _Anlage_. We have been unable to give a perfectly
satisfactory translation of this word in its technical meaning. We have
received some comfort, though but little help, from the experience of
the translators of similar works. Selmar Schoenland, in translating from
Weismann, renders it variously as "germ," "germ of structure," "germ (of
Naegeli)," "germ of Naegeli," "Naegeli's preformed germ of structure,"
"preformed germs," "tendency." Another translator renders the word as
"constitutional element." The translation, "determinant," which we have
selected is an appropriation of an analogous but not absolutely
identical technical term from Weismann's _Germinal Selection_. The use
of the word in this connection is open to the objection that it has
previously been used technically for a somewhat different idea by
another author. M. C. Potter, in his translation of Warming's
_Systematic Botany_, following Dr. E. L. Mark, renders the word _Anlage_
as "fundament." Dr. H. C. Porter, in his translation of the _Bonn
Text-Book of Botan