An improved, ultrasonic auxotonic transducer for use with isolated tissues

A new type of auxotonic transducer is described which utilises ultrasonic (40 KHz) radiation as an indirect means of detecting length changes in isolated tissues. The transducer is very sensitive to small changes in tissue length and is electrically stable with an adequate frequency response suitable for detecting changes in a wide range of isolated tissues. The transducer does not require an external bridge circuit or external amplification to provide a DC signal adequate to drive a pen recorder (0--1 mV). Applications of the transducer to pharmacological experiments are shown.