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PHYSICS: J. P. MI N TON 
Proc. N. a. S. 
that these patients were hearing in these opposite ears and that they were 
totally deaf in the other ears, as diagnosed. However, the moistened 
finger was placed in the ear which was not being tested and in the case of 
both patients the sensation of sound disappeared when the receiver was 
removed a cm. or so from the ear. They were able to hear when the 
receiver was brought close to but not in contact with the ear and they were 
unable to hear when the receiver was placed in contact with the bones of 
the head. There was also present the possibility that these two patients 
were not hearing the tones in the tested ears but through the eustachian 
tubes and the mouth to the opposite ears. Sufficient data are at hand, it 
is beheved, to negate such a conclusion as this. It was apparent, then, 
that both patients heard by air conduction with the ears diagnosed as 
totally deaf. The diagnosis, of course, rested upon the fact that the 
structure of the cochlea was known to have been completely destroyed by 
disease and an operation in one of the cases. In spite of this destruction, 
however, both patients heard all the tones up to 5000 d. v. and their audi- 
tory nerve systems responded in a normal manner. 
d. Two additional cases of true nerve deafness will be cited. The 
curves for these are shown in figure 4. Curves 1 and 2 are for a girl 20 
years old whose ears were in perfect condition at the time of the test. 
She was affected on one side only by paralysis of the facial, auditory and 
vestibular nerves. These three nerves join one another at a definite and 
known location in the head. Since all three of the nerves were simulta- 
neously affected and since they recovered at the same time, the exact loca- 
tion of the lesion was definitely known to the otologist. Curve 1 for this 
case shows an abrupt break between 400 and 500 d. v. At pitches below 
the break all the tones were heard as some sort of a noise corresponding to 
the noise referred to in the discussion of the curves in figure 1. The noise 
rather than a tone was present even when two or three thousand times as 
" much current was passing through the receiver as was required for audi- 
tion by a normal ear. Above the break in the curve the tones were per- 
ceived as pure ones at intensities only slightly greater than were required 
by normal ears. Thus, the nerves, stimulated in a perfectly normal 
manner, would not transmit the sensation of a pure tone at any of the 
pitches below the break but would transmit the sensations undistorted 
at all pitches above this point. A lesion, then, in the nerve proper may 
prevent the formation and transmission to the brain of a stimulus corre- 
sponding to a pure tone. 
This patient was first tested on February 4, 1921, and was again tested 
on March 7, 1921. During this period she had recovered completely and 
her hearing as shown by Curve 2 in figure 4 was equivalent to or better 
than normal. So, with the disappearance of the cause of the paralysis 
there was an immediate return to normal hearing and pitch perception. 
