This article examines the importance of sound in medical and musical circles of the French Enlightenment. Sound and listening in medicine were highlighted in 1756 by the Montpellier doctor Theophile de Bordeu, in his work on pulse. Pulse recognition, according to Bordeu, depended not only on the tactile abilities of the doctor but also on his skills in auditory perception. Doctors were required to memorise various acoustical patterns, then match them to the live pulse pattern of the patient perceived during observation. The Enlightened medical physician, like the musician, relied on his ear to communicate knowledge and understanding.