From cut forked Bar males which had been subjected for about 25 seconds to sound waves with a frequency of 285,000 vibrations per second, and then mated to doubleyellow females, there were raised a total of 26,135 flies. Among these were found 52 abnormalities of about 10 different types that were not inherited. There was also found a mottled eye mutation, which is "ever-sporting." No mutations or reversions were found at the Bar locus among a total of 20,857 males from the control and treated flies. The evidence is inconclusive that the abnormalities and the mutations were caused by the treatment, but it is definitely shown that supersonic vibrations of the intensity used and under the conditions of the experiment do not produce effects comparable to those produced by X-rays and radium.