Heating of Haired and Hairless Mice in Sound Fields from 6 to 22 kc

Experiments have been conducted to provide a comparison of heat absorption by haired and hairless mice in high-intensity airborne sound fields. At 18–20 kc, threshold intensities for heating of the mice were found to be about 144±2 db for haired animals and 155±2 db for hairless animals. From 6–22 kc effectiveness of the sound in heating the mice increased with frequency. Absorption coefficients computed from the data were found to be higher at higher frequencies for both types of animals. Death time was found to be dependent upon intensity and frequency of the sound waves, external covering of the animals, and the portion of the animal exposed to the intense part of the soundffield. At frequencies of 18 and 22 kc localized burns were evident on hairless animals, and these were studied. The configuration of the sound field and its relation to the results is discussed. Measurements made with and without the presence of a hairless mouse demonstrated the effect of the animal body on the sound field at 162 db and 6, 12, 18, and 22 kc.