Biological and psychological effects of ultrasonics.

Ultrasonic and also sonic waves of high intensity may produce discomfort and even injury. The dominant biological effects of various parts of the frequency spectrum are summarized. “Discomfort” implies that some sense organ is affected; but some combinations of intensity, frequency, and duration of exposure may possibly injure without the usual warning of discomfort. For the benefit of personnel working in high intensity sonic or ultrasonic fields we should establish both discomfort and danger contours, and there are wide gaps in our present knowledge. The Ultrasonics Panel of the Aeronautical Board desires particularly to receive any relevant well‐authenticated observations, either positive or negative, particularly concerning the effects of high‐intensity sound or ultrasonics on the sense organs and the nervous system. Casual publication of isolated, uncontrolled but spectacular “observations” may cause widespread popular apprehension and hinder the adoption of methods and instruments that involve ultra...