Invented in 1819, which device allows doctors to detect bodily sounds, such as a heartbeat?

The stethoscope, invented in 1819, is a medical instrument specifically designed to allow healthcare professionals to auscultate, or listen to, internal bodily sounds. It enables doctors to hear heartbeats, lung sounds, and other internal noises, thereby facilitating the assessment of a patient's physiological condition. The use of a stethoscope enhances the ability to diagnose medical issues by providing auditory feedback that indicates the status of organ function.

The other devices serve different purposes: a thermometer measures body temperature, a sphygmomanometer measures blood pressure, and an otoscope is used to examine the ears. Each of these tools has its specific role in medical diagnostics, but only the stethoscope is directly associated with the detection of heartbeats and other bodily sounds. Thus, the stethoscope is crucial in clinical settings for patient assessment and monitoring.