Laënnec’s invention of the stethoscope enabled physicians to study the sounds of the living heart and lungs in detail. His meticulous and revolutionary two-volume description of his findings, published in 1819, marked the beginning of the modern study of chest diseases, which could be more accurately diagnosed, more clearly understood, and more effectively treated.
During the 1750’s, Leopold Auenbrugger discovered that healthy and diseased
Physicians generally ignored percussion until Baron Jean Nicolas Corvisart des Marets, Napoleon I’s doctor, translated Auenbrugger’s work in 1808 as Nouvelle méthode pour reconnaitre les maladies internes de la poitrine par la percussion de cette cavité. With the blessing of a medical mind as prominent as that of Corvisart’s, percussion became immediately and almost universally accepted as a valuable diagnostic tool.
René-Théophile-Hyacinthe Laënnec was one of Corvisart’s students at the Hôpital de la Charité in Paris. Both men practiced the ancient technique of “auscultation,” which then meant listening to chest sounds by putting the ear directly on a patient’s body. Auscultation had many problems. It did not work with obese patients, exposed physicians to lice and contagious skin conditions, and could offend female patients. Worst of all, the sounds the doctor heard were faint and unclear. Percussion helped, but not much. As diagnosticians, both Corvisart and Laënnec wanted to amplify and clarify the sounds emitted by living chests.
In 1816, Laënnec examined an overweight woman with possible heart disease, but his examination was hampered because he could not get his ear close enough to her heart to hear it clearly. Remembering the principle that sound travels better through solids than it does through air, he spontaneously rolled up a few sheets of paper tightly into a tube and put one end on her chest and the other to his ear. The sounds he heard amazed him. He heard the heart more clearly and loudly and with less background noise than he had ever heard it before.
Laënnec and Corvisart
Soon after making his original paper stethoscope, Laënnec began crafting the instruments from wood. The stethoscopes he made were cylindrical, were about the size of a flashlight, and were called “monaural” because they could be used by one ear only. Laënnec realized that “binaural,” or two-eared, stethoscopes would be better but did not know how to create them.
Laënnec and some of his teachers, colleagues, and students were among the first scientists to understand the value of postmortem examination for studying disease. They shifted the focus of pathological research from the living to the dead, measuring their observations of cadavers against what they knew of healthy anatomy. Laënnec carefully described the chest sounds he heard in dying patients, then verified his hypotheses through autopsy and dissection, and thereby correlated specific sounds with specific diseases or conditions. His research with cadavers helped him diagnose diseases in living patients. His investigations contributed mostly to the knowledge of lung diseases, especially tuberculosis,
After three years of this research, Laënnec categorized and published his results in 1819 in the monumental two-volume work De l’auscultation médiate: Ou, Traité du diagnostic des maladies des poumons et du coeur. Sir John Forbes
In the few decades following Laënnec’s invention and his discoveries, many physicians across Europe and America augmented his work, further classifying chest sounds and increasing the diagnostic power of the monaural stethoscope. One of the earliest books in this genre was Victor Collin’s Des diverses méthodes d’exploration de la poitrine et de leur application au diagnostic de ses maladies (1824), which W. N. Ryland translated in 1829 as Manual for the Use of the Stethoscope: A Short Treatise on the Different Methods of Investigating the Diseases of the Chest. Pierre Adolphe Piorry
Other major researchers with the monaural stethoscope were Jean-Baptiste Bouillaud, who gave a classic description of endocarditis in 1835; William Stokes
Despite the obvious diagnostic advantages of the stethoscope, many physicians from the 1820’s to the 1850’s were reluctant to use it because its shape prevented them from simultaneously looking at and listening to the patient. Several inventors made clumsy attempts to overcome this inconvenience, but their primitive binaural stethoscopes did not transmit sound as accurately, loudly, or distinctly as the wooden monaural stethoscopes that were then common. Meanwhile, other inventors were having more success with improving the monaural stethoscope, selecting solid tubes to isolate heart sounds, using hollow tubes to isolate lung sounds, and experimenting with different kinds of wood, as well as ivory
The first successful binaural stethoscopes emerged during the 1850’s through the separate efforts of Arthur Leared
American physician Austin Flint
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Duffin, Jacalyn Mary. To See with a Better Eye: A Life of Laënnec. Princeton, N.J.: Princeton University Press, 1998. The standard biography on Laënnec. -
Kervran, Roger. Laënnec: His Life and Times. New York: Pergamon, 1960. Another good biography. -
Reiser, Stanley Joel. Medicine and the Reign of Technology. New York: Cambridge University Press, 1978. The second chapter of this work, “The Stethoscope and the Detection of Pathology by Sound,” places Laënnec’s invention within the context of diagnostic improvements that began in the eighteenth century. -
Rogers, Spencer Lee. The Monaural Stethoscope. San Diego, Calif.: Museum of Man, 1972. Appraises the fundamental technology of early stethoscopes. -
Sterne, Jonathan. “Mediate Auscultation, the Stethoscope, and the ’Autopsy of the Living’: Medicine’s Acoustic Culture.” Journal of the Medical Humanities 22, no. 2 (June, 2001): 115-136. Sterne examines the central place of the stethoscope in nineteenth century medical thought.
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