Abstract: A device for comforting and/or inducing sleep in an infant comprising a hollow body or other vibration transmitting means disposable at least partially beneath an infant's body or beneath or within a mattress or other body upon which an infant is laid, the space within the hollow body when provided, containing only a liquid and having at least one moveable or flexible wall portion or region permitting the body to change in volume in response to a change in the pressure of the liquid within the hollow body, the hollow body being in liquid communication or the transmitting means being in mechanical connection with a signal generator by means of an elongate tube or rod respectively whereby the signal generator can be placed at location remote from the hollow body or transmitting means, the signal generator, in use, producing pressure pulses in the liquid contained within the hollow body or vibrational movement of a predetermined pattern of varied frequency and magnitude, the pressure pulses causing vibrational m