1879.] 



Dr. B. W. Richardson on the Audiometer. 



69 



ing the value of hearing in those who are deaf, and in determining 

 the relative values of the two organs of hearing. In one instance, 

 already, I have been able by its means to detect in a person who was 

 supposed to be equally deaf on both sides, that on one side the hearing 

 is perfect close up to zero, while on the other side nine-tenths of the 

 hearing is lost. 



3. In other forms of diagnosis I have found the instrument useful. 

 In a young person suffering from acute anaemia the hearing was so de- 

 fective that on the right side it failed to detect sound at 18°, and on 

 the left side at 15°. In ten days, during which, under a new regimen, 

 great improvement took place in strength and general condition, the 

 power of hearing had so much improved that the right ear was good 

 down to 12°, and the left to 3° ; an improvement of 6° on the right, 

 and of 12° on the left side. 



In another person who was subject to repeated vertigo, the giddi- 

 ness occurring three or four times a-day, the hearing was so defective 

 that although the external ear on each side was clear and the tympanum 

 natural, no sound could be heard below 30°, Under complete rest and 

 attention to diet, the vertiginous attacks were in a few days removed 

 altogether, and with that removal there was gain of hearing, on both 

 sides equally, up to 5° on the audiometric scale. 



4. The instrument may be used to differentiate between deafness 

 through the external ear and deafness from closure of the Eustachian 

 tube, — throat deafness.. In my own case I fail to detect sound by the 

 mouth at 170°, and this I find is a fair average in those who are 

 healthy. It represents the comparative value of communication by 

 sound through the Eustachian canal and the external ear. 



5. The instrument promises to be very useful in detecting the effects 

 in the body of those agents which quicken or excite the circulation, 

 such as alcohol and other similar chemical substances. I have some 

 observations on these points in reserve for a further report. 



6. The instrument promises to be of great service in determining 

 the value of artificial tympanums in instances of deafness due to im- 

 perfection or destruction of the natural tympanum. The cotton arti- 

 ficial tympanums introduced originally by the late Dr. Yearsley, and the 

 membranous tympanums introduced by the late J. Toynbee, F.R.S., 

 have proved of much service ; and, by means of the audiometer, I have 

 been able very accurately to test their respective merits and to com- 

 pare both with tympanums made of other material. The inquiry has 

 Jed me to test different metals for this purpose, and to. find in fine 

 gold the substance for making the most useful and effective artificial 

 drum. The Messrs. Ash, of Broad Street, have made- for me various 

 forms of gold drums, the best of which, perhaps, is a little cylinder 

 which, with other forms, is placed before the Society. With one of 

 these cylinders I was able to give to a young gentleman who had lost 



