Abstract: A transmitter for mechanical oscillations of variable frequency and an oscillation pickup for determination of the mechanical characteristic frequency of blood vessels, tendons, bones or similar organs in a body, by which these organs act as coupling members between the transmitter and the oscillation pickup. The transmission means from the transmitter to the body and from the body to the oscillation pickup are accommodated inside of a common support tube. One end of the support tube is rigidly connected with the support frame, in which support frame, the transmitter and the oscillation pickup are installed mutually decoupled, with even amplifiers or the like being installed, connected after the oscillation pickup, if necessary under the circumstances. The other end of the support tube is able to be set on the body.