IN 1816, THE FRENCH PHYSICIAN RENÉ LAENNEC collided head-on with propriety, and the stethoscope was born. Laennec suspected a young lady in his care of suffering from heart distress but felt restrained from placing his ear to her chest to confirm the diagnosis. Searching for a solution, he recalled an acoustic phenomenon in which a person listening at one end of a hollow pole could clearly hear someone scratching a pin at the other. He rolled a piece of paper into a tube and placed it against the woman’s chest, allowing a discreet distance from which to listen. Laennec was stunned to hear her heartbeat and her breathing much more loudly and clearly than he ever had with ear to chest.

By using his monaural (single-ear) stethoscope and studying autopsies, Laennec pioneered the diagnosis of a number of conditions, including tuberculosis and pneumonia. One hundred ninety years later, although the stethoscope has evolved (to become biaural, for one thing), it remains largely unchanged and still highly effective. Moreover, it has come to symbolize the “laying on of hands” aspect of the doctor-patient relationship that patients crave. But among young physicians its use seems to be something of a lost art: One study found that students and interns were able to detect heart and other internal problems only 38% of the time with the correct use of a stethoscope.

The study’s lead author, Jeanne DeCara, a cardiologist at the University of Chicago, says younger doctors rely increasingly on such technologies as EKGs and ultrasounds, and so don’t learn to trust their senses. But the instrument won’t disappear from doctors’ necks: Several companies have developed digital stethoscopes, which amplify and record barely audible sounds that can be played back, then looped and run through a database of normal and diseased states.

Increasingly, stethoscopes will be used in conjunction with other technologies. “In our study, doctors who used both a stethoscope and a handheld ultrasound made the most accurate diagnoses,” says DeCara. “And the great thing with this combination is that doctors are still laying on hands.” The very thing Laennec aimed to avoid.