ven when called 'unconscious,' suggests mind; for, as we have seen, the
automatic character implied by this term 'unconscious' presupposes
foregone experience.... The mnemic theory then, if it is to be worth
anything, seems to me clearly to require not merely physical records or
'engrams,' but living experience or tradition. The mnemic theory will
work for those who can accept a monadistic or pampsychist interpretation
of the beings that make up the world, who believe with Spinoza and
Leibniz that 'all individual things are animated albeit in divers
degree'" (pp. 55-6).

Perhaps the best and most ingenious treatment of memory and heredity
from a physical standpoint is that offered by E. Rignano in his book,
_Sur la transmissibilite des caracteres acquis_.[516] Rignano seeks to
construct a physico-chemical "model" which will explain both heredity
and memory.

His system, which is based more firmly upon the facts of experimental
embryology than Semon's, postulates the existence of "specific nervous
accumulators." The essential hypothesis set up is that every functional
stimulus is transformed into specific vital energy, and deposits in the
nucleus of the cell a specific substance which is capable of
discharging, in an inverse direction, the nervous current which has
formed it, as soon as the dynamical equilibrium of the organism is
restored to the state in which it was when the original stimulus acted
upon it. These specific nuclear substances, different for each cell, are
accumulated also in the nuclei of the germinal substance, constituting
what Rignano calls the central zone of development. That is to say, each
functional adaptation changes slightly the dynamical equilibrium of the
organism, and this change in the system of distribution of the nervous
currents leads to the deposit in the central zone of development of a
new specific substance. In the development of the next individual this
new specific element enters into activity, and reproduces the nervous
current which has formed it, as soon as the organism reaches the same
conditions of dynamical equilibrium as those obtaining when the stimulus
acted on the parent.

Development can thus be regarded as consisting of a number of stages, at
each of which new specific elements enter automatically into play and
lead the embryo from that stage to the stage succeeding. The germinal
substance on this theory of Rignano's is to be regarded as being
composed of a large num