unds the action-theory of Muensterberg[25] has
proposed the hypothesis that cerebral centers fail to mediate
consciousness not merely when no stimulations are transmitted to them,
but rather when the stimulations transmitted are not able to pass
through and out. The stimulation arouses consciousness when it finds a
ready discharge. And indeed, in this particular case, while we have no
other grounds for supposing stimulations _to_ the visual centers to be
cut off, we do have other grounds for supposing that egress _from_
these cells would be impeded.

[25] Muensterberg, Hugo, 'Grundzuege der Psychologie,' Leipzig,
1900, S. 525-561.

The occipital centers which mediate sensations of color are of course
most closely associated with those other centers (probably the
parietal) which receive sensations from the eye-muscles and which,
therefore, mediate sensations which furnish space and position to the
sensations of mere color. Now it is these occipital centers, mediators
of light-sensations merely, which the experiments have shown most
specially to be anaesthetic. The discharge of such centers means
particularly the passage of excitations on to the parietal
localization-centers. There are doubtless other outlets, but these are
the chief group. The movements, for instance, which activity of these
cells produces, are first of all eye-movements, which have to be
_directly_ produced (according to our present psychophysical
conceptions) by discharges from the centers of eye-muscle sensation.
The principal direction of discharge, then, from the color-centers is
toward the localization-centers.

Now the experiment with falsely and correctly localized after-images
proves that before the anaesthesia all localization is with reference
to the point of departure, while afterwards it is with reference to
the final fixation-point. The transition is abrupt. During the
anaesthesia, then, the mechanism of localization is suffering a
readjustment. It is proved that during this interval of readjustment
in the centers of eye-muscle sensation the way is closed to oncoming
discharges from the color-centers; but it is certain that any such
discharge, during this complicated process of readjustment, would take
the localization-centres by surprise, as it were, and might
conceivably result in untoward eye-movements highly prejudicial to the
safety of the individual as a whole. The much more probable event is
the following:

Although Schwa