150 



Scientific Proceedings (127) 



D. This indicated that the subject had practically returned to 

 normal although a pronounced tinnitus was reported. 

 Test E. 



This made at 4:30 the same afternoon is shown which practi- 

 cally coincides with the normal amount of acuity but with the 

 tinnitus about the same as in the morning. The tinnitus gradu- 

 ally disappeared during the next twenty-four hours. 

 Test F. 



There still remained the problem of whether the tinnitus itself 

 masked the note or whether it was the toxic effect of the drug 

 which gave rise to the larger than normal variation in passing 

 from one scale to another. It is well known that tinnitus may 

 be produced by an exposure to loud sounds and it was decided 

 to put this to a test. The subject was placed with his head three 

 feet in front of a telephone receiver which emitted an extremely 

 loud note of 1300 p.p.s. This note was sufficiently loud to be 

 heard outside of the building. After three and one-half hours 

 exposure, the subject was immediately subjected to the test over 

 the range from 1000 - 1800 p.p.s. No material alteration was 

 noted in the acuity over the entire range nor was the exact point 

 of the pitch of 1300 influenced. The tinnitus and sensation of 

 feeling of fullness in the ears was as apparent as in the forty 

 grain quinine test and did not entirely disappear for thirty six 

 hours. This seems to show that while the tinnitus appeared sub- 

 jectively to distract the attention in the test on quinine, it could 

 not in itself be held responsible for the decreased efficiency of 

 hearing. 



Conclusions 



We feel the following conclusions may be drawn from these 

 experiments on quinine : 



First. A twenty five grain dose did not materially influence 

 the acuity of hearing. 



Second. A forty and a seventy five grain dose produced a 

 pronounced decrease in acuity. The larger dose apparently af- 

 fected the lower part of the scale (256 to 1000) more markedly 

 than the upper part (1000 - 1800). We are, of course, not sure 

 of the amount of drug absorbed and will gladly turn over the 

 subcutaneous or intravenous injection to someone else. There 

 can be no question that the drug was not pushed to the limit 

 in Test C. 



