160 
PHYSICS: R. L. WEGEL 
Proc. N. a. S. 
Since all speech sounds may be considered as stimuli composted of 
various frequency components of certain intensities the sensation caused 
by such a sound may be represented on this plot by points, or by a line 
running provided the sound has a band spectrum. If the points or line 
falls within the sensation area the sound is audible. It is easy to see that 
if the points or the part of the line which represent those frequency com- 
ponents most essential to interpretation of the sound, fall within any of 
these abnormal areas, the sound is very likely to be misinterpreted. This 
adds a further source of loss in articulation to that already observed due 
to a narrowing of the sensation range. 
Many practically normal ears have very small abnormal areas. They 
have always been found near minimum audibility and therefore have little 
influence on the hearing of the individual. They seem to be associated 
with catarrhal conditions although this cannot be stated positively. 
8. Binaural Sense. — The normal individual has learned to interpret 
the differential sensations of the two ears to an advantage. It helps him 
to locate the direction from which sounds come, to have a sort of sense of 
orientation with respect to sounds approaching from different directions, 
and whether for physical or for purely psychological reasons to assist in 
focusing of the attention on one sound of a large number. Two ears also 
assist the individual in perceiving equally well sounds coming from differ- 
ent directions. When one ear becomes insensitive even though the loss 
is small, the use of the binaural sense disappears and after a time is not 
missed. For the binaural sense to be most effectively utilized it is neces- 
sary that the ears be very nearly alike. In many cases of deafness one 
ear is much more deaf than the other and the subject does not utilize the 
binaural sense. When a binaural deaf set is made and fitted to a person 
with compensating sensitivity for the two ears so that both hear the sounds 
equally loud, the sensation is usually so novel, that if the patient is actually 
able to experience a binaural sensation he is very much pleased. Usually, 
however, he has not used his binaural sense for so long a time that it takes 
a considerable amount of practice before he is able to have binaural ex- 
periences. It may be noted in this connection that the same experience 
is encountered in fitting the eyes with glasses. It is found that people 
with two eyes which are slightly different do not see stereoscopically but 
if glasses are made so as to compensate and make the eyes nearly alike it 
usually takes a certain time of practice before the sense of perspective can 
be brought back. 
An audiometer similar to the one used in the measurements recorded 
and a binaural deaf set have been set up here for inspection. 
