amplification of his theory of selection is, in my
opinion, the work of Richard Semon: _Die Mneme als erhaltendes Prinzip
im Wechsel des organischen Geschehens_.[133] He offers a psychological
explanation of the facts of heredity by reducing them to a process of
(unconscious) memory. The physiologist Ewald Hering had shown in 1870
that memory must be regarded as a general function of organic matter,
and that we are quite unable to explain the chief vital phenomena,
especially those of reproduction and inheritance, unless we admit this
unconscious memory. In my essay _Die Perigenesis der Plastidule_[134]
I elaborated this far-reaching idea, and applied the physical
principle of transmitted motion to the plastidules, or active
molecules of plasm. I concluded that "heredity is the memory of the
plastidules, and variability their power of comprehension." This
"provisional attempt to give a mechanical explanation of the
elementary processes of evolution" I afterwards extended by showing
that sensitiveness is (as Carl Naegeli, Ernst Mach, and Albrecht Rau
express it) a general quality of matter. This form of panpsychism
finds its simplest expression in the "trinity of substance."

To the two fundamental attributes that Spinoza ascribed to
substance--Extension (matter as occupying space) and Cogitation
(energy, force)--we now add the third fundamental quality of Psychoma
(sensitiveness, soul). I further elaborated this trinitarian
conception of substance in the nineteenth chapter of my _Die
Lebenswunder_ (1904),[135] and it seems to me well calculated to
afford a monistic solution of many of the antitheses of philosophy.

This important Mneme-theory of Semon and the luminous physiological
experiments and observations associated with it not only throw
considerable light on transformative inheritance, but provide a sound
physiological foundation for the biogenetic law. I had endeavoured to
show in 1874, in the first chapter of my _Anthropogenie_,[136] that
this fundamental law of organic evolution holds good generally, and
that there is everywhere a direct causal connection between ontogeny
and phylogeny. "Phylogenesis is the mechanical cause of ontogenesis;"
in other words, "The evolution of the stem or race is--in accordance
with the laws of heredity and adaptation--the real cause of all the
changes that appear, in a condensed form, in the development of the
individual organism from the ovum, in either the embryo or the larva