Effect of Certain Drugs on Acuity of Hearing 147 



parts of the curve represent the greater sensitivities and on the 

 logarithmic scale equal differences in height have much more 

 nearly equal importance in audition than if plotted on a linear 

 scale. Also small values are not obscured at the bottom of the 

 paper. This logarithmic sensitivity seems to be the most logical 

 way to express sensitivity. 



Three curves for minimum audibility are presented in Chart 

 1. The frequencies in the range tested are indicated on the base 

 line and extend from 256 to 3700 p.p.s. The ordinate quantities 

 are expressed in terms of ergs per square centimeter per second 

 and are plotted on a logarithmic scale from 10" 6th to 10" 10th power. 

 The first curve to be noted is shown by a dotted line and rep- 

 resents the acuity of hearing for the right ear of the subject's 

 fifteen year old daughter taken with the same apparatus. The 

 curve is a normal one and may therefore be used as a guide to 

 the variations from the normal in the two ears of the subject 

 himself. The acuity of the right ear of the subject has been 

 entered as a broken line with light circles while that for the left 

 ear is a continuous line with black circles. The dots on the line 

 indicate the separate frequencies tested and calculated for pur- 

 poses of the graphic presentation. 



The three curves follow a fairly normal picture until the 

 region of 1800 p.p.s. is attained. At no point do the subject's 

 ears differ from that of the control by more than a factor which 

 might be considered beyond a reasonable error in attention. The 

 left ear shows one pronounced spot of decreased acuity (a factor 

 of about 1000 when compared with the control). The lessened 

 acuity begins at 2250 and returns to the normal for this age (43) 

 at 3000. The right ear, on the contrary, shows three areas of 

 decreased acuity; one pronounced spot at 2450 and two less 

 pronounced ones at 1920 and at 2920 p.p.s. These are separated 

 by two peaks, one at 2200 and another at 2800. Both ears dis- 

 play a drop-off at the neighborhood of 3400. (Age change?). 



These two curves are interesting because the subject was 

 unaware of any areas of decreased acuity, and even at the pres- 

 ent time is not conscious of their presence. The chart gives the 

 reason why the range of 1000-1800 p.p.s. was selected for the 

 tests on antipyretics. If comparisons are to be made of effects 

 on the two ears, this may be done only below the frequency of 

 1800. The right ear has been chosen for presenting graphically 



