The stethoscope is an implement for listening to the internal sounds of the body. It is widely used by doctors and veterinarians to gather data from their patients, in particular, breathing and heart rate. The stethoscope may be acoustic or electronic, and some modern stethoscopes record sounds, as well.
The Stethoscope: An Instrument Born of Embarrassment
The stethoscope was invented in 1816 by the French physician René Théophile Hyacinthe Laënnec (1781-1826) at the Necker-Enfants Malades Hospital in Paris. The doctor was treating a female patient and was embarrassed to use the traditional method of Immediate Auscultation, which involved the doctor pressing his ear to the patient's chest. (Laënnec recounts that the method was "rendered inadmissible by the age and sex of the patient.") Instead, he rolled up a sheet of paper into a tube, which allowed him to hear his patient's heartbeat. Laënnec's embarrassment gave rise to one of the most important and ubiquitous medical instruments.
The first stethoscope was a wooden tube similar to the "ear horn" hearing aids of the time. Between 1816 and 1840, the various practitioners and inventors replaced the rigid tube with a flexible one, but documentation of this phase of the device's evolution is spotty. We do know that the next leap forward in stethoscope technology took place in 1851 when an Irish doctor named Arthur Leared invented a binaural (two-ear) version of the stethoscope. This was refined the next year by George Cammann and put into mass production.
Other improvements to the stethoscope came in 1926, when Dr. Howard Sprague of Harvard Medical School and M.B. Rappaport, an electrical engineer, developed a double-headed chest piece. One side of the chest piece, a flat plastic diaphragm, rendered higher-frequency sounds when pressed to the patient's skin, while the other side, a cup-like bell, allowed sounds of a lower frequency to be discerned.