and yet which would not have been
excited by the normal play of the neurons. Quite secondary remains the
question of how these reproduced images finally appear in consciousness,
that is, whether they appear with reference to earlier happenings and
are thus felt as remembrances, or whether they enter as independent
imaginations, or whether they finally, under special conditions, take
the character of real, new perceptions. The latter case is well-known in
crystal-gazing, where long-forgotten memory ideas project themselves
into the visual field like hallucinations. But for the theory of the
subconscious, even these uncanny crystal visions do not mean more than
the simplest awakening of the experience of a landscape image of
yesterday.

We turn to a second group of facts and again we have no fault to find
with the observation of the facts, even of the most surprising and
exceptional ones. Our objection refers to the interpretation of them.
This second group contains the active results of such physiological
nervous dispositions. In the first group, the dispositions come in
question only as conditions for a new excitement which was accompanied
by mental experience. In this second group, the dispositions are causes
for other physiological processes which either lead to actions or to
influences on other mental processes. The dispositions are here working
like the setting of switches which turn the nervous process into special
tracks. In the simple cases, of course no one doubts that a purely
physiological basis is involved. The decapitated frog rubs its skin
where it is touched with a drop of muriatic acid in a way which is
ordinarily referred to the trained apparatus of his spinal cord, as no
brain is left, and the usefulness of the action and its adjustment is
very well understood as the result of the connecting paths in the
nervous system.

From such simple adjustment of reactions of the spinal cord, we come
step by step to the more complex activities of the subcortical brain
centers, and finally to those which are evidently only short-cuts of the
higher brain processes. That we react at every change of position with
the right movements to keep our bodily balance, that we walk without
thinking of our steps, that we speak without giving conscious impulse
for the various speech movements, that we write without being aware of
the motor activity which we had to learn slowly, that we play the piano
without thinking of the sp