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Transactions Texas Academy of Science. 
spatial conception is greater, we find that this greater power is due 
to a synthetic process, as James and Heller both point out. An 
object too large to be handled in the ways above mentioned must be 
investigated piece by piece successively by the analyzing touch. These 
separate and successive images are combined, synthesized into one 
tactile conception. This assumes the nature of a model of such size 
that it might be dealt with in the simpler analytic way. When this 
stage of development has been reached, a conception may be formed 
also from description. Here the elements of the description, if they are 
objects already known, are used in the same way as the successive 
impressions when the synthetic touch is used. In this manner the 
scope of spatial ideas can be greatly enlarged. 
Heller, following F. Hitschmann, who published an article entitled 
Ueber Begruendung einer Blindenpsychologie von einen Blinden, in 
Vol. Ill of the Zeitschrift fur Psychologie und Physiologie der Sin- 
nesorgane, expresses the opinion that only very few blind persons 
have spatial conceptions which are at all comparable in adequacy 
with those of the seeing., Only those whose work or inclination leads 
them to exercise the touch habitually and with attention acquire 
a marked development of space conception. Others have almost no 
space ideas beyond those of their own bodies. They attach to things 
which it would seem ought to be spatial, other marks. Thus, particu- 
lar persons are represented by the sound of the voice, the touch and 
shape of the hand, or by the sound of the walk. This substitution 
of other marks for spatial ones in the ideas of things, which may take 
place with all persons, must predominate with the blind, as one under- 
stands from their difficulty in adequate space perception. 
