Introduction
The material herein represents excerpts from the literature from October, 1956, to October, 1957. This year the German literature was abstracted by Dr. Satz. An attempt was to cull from the ultrascientific reports of the acoustic physicists such material as was thought useful to the practicing otologist, who may not have the extensive facilities required for many of these investigations.
Hearing Aids
Ewertsen and Ipsen1 state that measurements show that the reproduction of high frequencies is better when an ear mold with a short and wide canal is used rather than one with a long and narrow canal. With the so-called secret ear the high frequencies are cut off more markedly.Naunton2 examined a group of partially deafened adults after varying periods of hearing aid use to determine whether the hearing aids had led to a deterioration of unaided hearing. No significant change in hearing could be