in the proper work of the whole are called tissue-cells. In virtue
of their activities, their growth and reproductive power are limited-
-much more in Animals than in Plants, in Higher than in Lower beings.
It is these tissues, or some of them, that receive the impressions
from the outside which leave the imprint of memory. Other cells,
which may be closely associated into a continuous organ, or more or
less surrounded by tissue-cells, whose part it is to nourish them,
are called "secondary embryonic cells," or "germ-cells." The germ-
cells may be differentiated in the young organism at a very early
stage, but in Plants they are separated at a much later date from the
less isolated embryonic regions that provide for the Plant's
branching; in all cases we find embryonic and germ-cells screened
from the life processes of the complex organism, or taking no very
obvious part in it, save to form new tissues or new organs, notably
in Plants.


Again, in ourselves, and to a greater or less extent in all Animals,
we find a system of special tissues set apart for the reception and
storage of impressions from the outer world, and for guiding the
other organs in their appropriate responses--the "Nervous System";
and when this system is ill-developed or out of gear the remaining
organs work badly from lack of proper skilled guidance and co-
ordination. How can we, then, speak of "memory" in a germ-cell which
has been screened from the experiences of the organism, which is too
simple in structure to realise them if it were exposed to them? My
own answer is that we cannot form any theory on the subject, the only
question is whether we have any right to INFER this "memory" from the
BEHAVIOUR of living beings; and Butler, like Hering, Haeckel, and
some more modern authors, has shown that the inference is a very