In the last section, I gave an account of some experiments in the
localization of touch sensations which were designed to show how,
under varying pressure, the points in the filled distance are
displaced or fused and disappear entirely from the judgment. Our
earliest experiments, it will be remembered, yielded unmistakable
evidence that short, filled distances were underestimated; while all
of the secondary experiments reported in the last section have pointed
to the conclusion that even these shorter distances will follow the
law of the longer distances and be overestimated under certain
objective conditions, which conditions are also more nearly parallel
with those which we find in the optical illusion. I wish now to give
the results of another and longer set of experiments in the
localization of a manifold of touch sensations as we find them in this
same illusion for filled space, by which I hope to prove a direct
relation between the function of localization and the spatial
functioning proper.

These experiments were made with the same apparatus and method that
were used in the previous study in localization; but instead of two
points of different weights, four points of uniform weight were
employed. This series, therefore, will show from quite another point
of view that the fusion which takes place, even where there is no
difference in the weight, is a very significant factor in judgments of
distance on the skin.

[Illustration: Fig. 4.]

I need hardly say that here, and in all my other experiments, the
subjects were kept as far as possible in complete ignorance of the