e of the word) of their having done those actions when they were in
the persons of their parents; which memory, though dormant until
awakened by the presence of associated ideas, becomes promptly kindled
into activity when a sufficient number of these ideas are reproduced.

This, I gather, is the theory put forward by Professor Hering, of whose
work, however, I know no more than is told us by Professor Ray
Lankester in an article which, appeared in 'Nature,' July 13th, 1876.
This theory seems to be adopted by Professor Haeckel, and to receive
support from Professor Ray Lankester himself. Knowing no German, I have
been unable to make myself acquainted with Professor Hering's position
in detail, but its similarity to, if not identity with, that taken by
myself subsequently, but independently, in 'Life and Habit,' seems
sufficiently established by the following extracts; it is to be wished,
however, that a full account of this lecture were accessible to English
readers. The extracts are as follows:--

"Professor Hering has the merit of introducing some striking phraseology
into his treatment of the subject which serves to emphasize the leading
idea. He points out that since all transmission of 'qualities' from cell
to cell in the growth and repair of one and the same organ, or from
parent to offspring, is a transmission of vibrations or affections of
material particles, whether these qualities manifest themselves as form,
or as a facility for entering on a given series of vibrations, we may
speak of all such phenomena as 'memory,' whether it be the conscious
memory exhibited by the nerve cells of the brain or the unconscious
memory we call habit, or the inherited memory we call instinct; or
whether, again, it be the reproduction of parental form and minute
structure. All equally may be called the 'memory of living matter.' From
the earliest existence of protoplasm to the present day the memory of
living matter is continuous. Though individuals die, the universal
memory of living matter is carried on.

"Professor Hering, in short, helps us to a comprehensive conception of
the nature of heredity and adaptation, by giving us the term 'memory'
conscious or unconscious, for the continuity of Mr. Herbert Spencer's
polar forces, or polarities of physiological units.

. . . . . .

"The undulatory movement of the plastidules is the key to the mechanical
explanation of all the essential phenomena of life. The plastidules ar