When was the stethoscope invented?

Stethoscope - was invented by a French doctor, René Théophile Hyacinthe Laënnec, in 1816. His stethoscope was a perforated wooden cylinder one foot long, and he got the idea for it from the sight of children scratching one end of a wooden beam with a pin and listening to the transmitted sound at the other end. He put one end of the tube to his patient's chest and listened to noises made by the heart and lungs. He gathered evidence of what these sounds meant by comparing the various noises heard in living patients with the type of disease seen after they died. In 1819 he published his findings in one of the great books of medicine De I'Auscultation Médiate, and the stethoscope soon came into general use. Auscultation (listening to sounds within the body) is most commonly used in diagnosing diseases of the heart and lungs. Nowadays a stethoscope is generally binaural (for both ears) and has two flexible rubber tubes attaching the chestpiece to spring connected metal tubes with earpieces. In listening it is often necessary to use both a bellshaped, open ended chestpiece for low pitched sounds, and a flat chestpiece covered with a semi rigid disc or diaphragm for high pitched sounds. Many modern stethoscope have both kinds of chestpieces, readily interchanged by turning a valve.