Laennec monoaural (one ear) stethoscope, late 19th century.

The stethoscope first devised in 1816 by the French physician, Rene Laennec (1781-1826) was constructed from a simple hollow tube. Stethoscopes were designed to help the physician diagnose diseases of the lungs, heart and vascular systems by listening to the internal rhythms and sounds of the human body. The familiar binaural (two ear) stethoscope was developed in the 1850s.