stimulated, just the part which in case 2 was not stimulated; and the
part which in case 2 was, is here not stimulated. Now here the false
streak is seen, together with just that portion of the correct streak
which in the previous case was not seen. The latter is relatively dim.

Thus it looks indeed as if the streak given during the first part of
an eye-movement is seen twice and differently localized. But one may
say: The twice-seen portion was in both cases on the fovea; this may
have been the conditioning circumstance, and not the fact of being
given in the early part of the movement.

We must then consider Fig. 3, case 4. Here the eye moves from _B_ to
_B'_, through the same arc of 40°. The wall _W_ is placed so that _L_
cannot be seen until the axis of vision has moved from _EB_ to _EL_,
but _then L_ is seen in direct vision. Its image falls full on the
fovea. But one streak, and that the correctly localized one, is seen.
This is like case 2, except that here the streak extending from _L_ to
the right quite reaches the final fixation-point _B'_. It is therefore
not the fact of a stimulation being foveal which conditions its being
seen in two places.

It should be added that this experiment involves no particular
difficulties of observation, except that in case 4 the eye tends to
stop midway in its movement when the spot of light _L_ comes in view.
Otherwise no particular training of the subject is necessary beyond
that needed for the observing of any after-image. Ten persons made the
foregoing observations and were unanimous in their reports.

This experiment leaves it impossible to doubt that the conjecture of
Schwarz, that the correct image is only the false one seen over again,