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Transactions Texas Academy of Science. 
range. It acts at a considerable distance. The blind person must rely 
almost wholly on touch, whose field is very limited. 
The term touch is here used in its broadest sense, not applying 
merely to the perceptions due to contact of a certain limited portion 
of the skin of the hand with an object, but including both those due 
to such contact with any part of the skin, the outer sense of touch, 
and such arising from motion of the parts of the body in the muscular 
strain and in the joints, inner sense of touch. The latter plays an 
important part in the spatial perceptions. 
Those who see seem generally to rely on sight alone for the space 
perceptions and conceptions, so that some writers deduce them en- 
tirely from this source, sometimes going so far as to deny the blind 
space-conception altogether (Platner at the end of the 18th century, 
cited by Heller). 
The sense of hearing, even if it should not have the power of giv- 
ing original space-perception, clearly does so after a sufficient de- 
velopment and practice. On this matter there is a considerable litera- 
ture. Many blind persons have given their testimony, which, how- 
ever, is quite conflicting. This conflict is due to the fact that most 
of the writers made no experimental investigation. They often as- 
cribed their perception to a peculiar sensitivitity in the skin of the 
face, and called the phenomenon facial perception. Psychologists, 
such as James and Wundt, have discussed this matter, and have 
reached the conclusion that it is chiefly due to the sense of hearing. 
Wundt admits the possibility of sensations being aroused in the skin 
of the forehead by the pressure of the air resulting from the ap- 
proach to an object, and Heller insists on this point rather strongly. 
John Yars, a blind student, in one of his articles in the Mentor, speaks 
of this matter, and remarks, that this perception takes place only 
when one is very near to an object, within a few inches, which agrees 
with Heller, and that therefore the blind can not derive much benefit 
from it. 
Drs. Mezes and Hilgartner conducted a series of experiments in 
this field ten years ago, and presented their results to this Academy 
in a paper read June 15, 1896. Their experiments brought out the 
paramount importance of the sense of hearing. When the face of 
the subject was covered with a pad made of two pieces of cotton cloth 
with absorbent cotton between them, while the ears were left free, 
the perception was undisturbed. When, on the other hand, the ears 
were stopped with bags of fish-skin filled with flour, or with putty 
and cotton, few cases of perception were noted, and these were always 
accompanied by other circumstances, such as walking from sun-shine 
into shade for instance, which rendered the results doubtful. 
