Effects of High Frequency Sound Waves on Protoplasm.

Abstract

The observations described in the following preliminary report were made by subjecting animal cells to the action of sound waves produced by a rapidly vibrating quartz crystal. The oscillating current was generated by a 250 watt tube connected in a modified Hartley circuit. The crystal lay between a heavy lower electrode and a light upper electrode of copper gauze in a crystallizing dish containing the dielectric liquid, usually xylene. The crystal vibrated at the rate of approximately 750,000 times per second.

Effects in Vitro. In this type of experiment the animals were placed in a test tube or similar vessel containing water and dipped into the dielectric over the vibrating crystal. Free-swimming Triturus larvae are rapidly killed, the gill filaments being torn away and areas of denuded surfaces exposed. Confirming the findings of Wood and Loomis, 1 the larger protozoa are killed by this method, while the smaller protozoa, being able to swim between the nodes of the stationary wave system set up in the water, escape unharmed. Spirostema, being relatively large, are quickly killed, Paramecia less rapidly, while the smaller protozoa are unaffected after many minutes. By means of a simple arrangement it was possible to observe the cells through the microscope while subjecting them to the sound waves. A drop containing the protozoa was placed on a microscopic slide and a cover glass laid over it. The slide was then laid across the oscillator dish. The sound waves were transmitted in this manner to the cells through the medium of the oscillator dish and the slide. Neglecting morphological details for the present, cell destruction is due to an actual disruption of the whole or of a part of the cell, to a gelation or coagulation of the protoplasm, and to a combination of the two effects.