Imagine for a moment the year 1800. A doctor is meeting with a patient – most likely in the patient’s home. The patient is complaining about shortness of breath. A cough, a fever. The doctor might check the patient’s pulse or feel their belly, but unlike today, what’s happening inside of the patient’s body is basically unknowable. There’s no MRI. No X-rays. The living body is like a black box that can’t be opened.

The only way for a doctor to figure out what was wrong with a patient was to ask them, and as a result patients’ accounts of their symptoms were seen as diseases in themselves. While today a fever is seen as a symptom of some underlying disease like the flu, back then the fever was essentially regarded as the disease itself.

But in the early 1800s, an invention came along that changed everything. Suddenly the doctor could clearly hear what was happening inside the body. The heart, the lungs, the breath. This revolutionary device was the stethoscope.

The inventor of the stethoscope was a French doctor named René Laennec. In medical school, he had learned to practice percussion – a technique in which doctors tap their fingers against a patient’s chest and listen to the sound to try and hear what’s going on inside.

One day, he tried percussing a patient but had trouble hearing. So he rolled up his notebook into a little cylinder and put one end on the patient’s chest and one end in his ear. He was so impressed by the quality of the sound that he decided to construct a device for listening to the internal sounds of the body.

The result was the original stethoscope. Laennec had invented a way to hear the inner workings of the human body. Now he needed to connect the sounds he was hearing with what was happening anatomically inside the patient’s body.

To do this, Laennec listened to people right before they died, and then connected these sounds to discoveries made during the autopsy. Soon, Laennec made some key discoveries using his stethoscope. For example, he found that when a person has fluid beneath their lungs, they make a bleating sound, kind of like a goat. A sound he called egophony. He also discovered sounds that tracked with the different stages of tuberculosis.

Laennec published his results, and soon doctors were making other important discoveries that changed the way people thought about disease. Little by little our entire understanding of disease shifted from one centered around symptoms to one centered around objective observation of the body. Medical language completely changed, as doctors invented new anatomical words for diseases, like Bronchitis, which means the inflammation of the bronchial tubes.

In parallel, the device evolved as well. In the 1840s, doctors began experimenting with flexible tubing and soon an Irish physician invented the binaural stethoscope design with two earpieces that we still use.

This evolving device got doctors thinking about disease in new ways, changing their dynamic with patients and giving doctors a lot more power. Before the stethoscope, to be sick, the patient had to feel sick. After the stethoscope, it didn’t matter what patients thought was wrong with them, it mattered more what the doctor found.

René Laennec actually felt that patient’s accounts of their own disease were still important, but the quest for objective information about disease was underway, and the stethoscope was just the beginning. Now we have X-rays, CT scanners and MRI and PET scans. All of these devices are basically trading upon the same paradigm that the stethoscope created: that doctors should be able to detect abnormalities inside the body to reach a diagnosis, regardless of how the patient is feeling.

These new technologies have led to so many important discoveries about the human body and disease. Today, we can spot tumors before they become life threatening and diagnose problems like high blood pressure before they causes heart disease. But this new way of thinking has also pushed doctors and patients farther apart. The doctor is no longer in your bedroom interviewing you about every detail of your experience.

René Laennec died in 1826 at the age of 45, mostly likely of tuberculosis, a disease he and his stethoscope helped us understand. It’s been 200 years since he first rolled up his note book and pressed it to that patient’s chest. Medicine looks completely different than it did back then, but somehow the stethoscope has endured.

It’s no longer a wooden cylinder, but to this day, when you walk into a doctor’s office for a routine exam, you can expect to feel the familiar stethoscope on your back.

But that could be changing. Powerful imaging technologies like ultrasound have made the stethoscope exam less critical to the diagnostic process. Medical students aren’t as good as using stethoscopes as they used to be, and across the board doctors today rely less on the stethoscope to make diagnoses. The rise of portable ultrasound has some doctors arguing that we don’t need the stethoscope anymore. They say that if you have that technology right at the bedside, why not use it right away? Ultrasound is an incredible tool, but it still isn’t widely available in many developing countries, and even in the United States it’s expensive. Right now the stethoscope functions as a screening tool so that patients don’t need to go get an expensive ultrasound unless they need one.

Dr. Andrew Bomback is a nephrologist and an assistant professor at Columbia. He still uses his stethoscope, but he says that in general doctors aren’t as good at listening to the body as they once were, and they rely on the stethoscope exam less and less to make a diagnosis. “It’s become almost a ritual more than an actual tool in terms of making diagnosis,” Bomback explains.

Regardless of how it’s used, the stethoscope remains omnipresent in our culture. Do a Google image search for doctor, and you will see what a physician is supposed to look like. The plurality of the doctors pictured on the first page of results are white men in white coats. Some of them are peering inside patient’s ears, others are writing something down on a clipboard. But all of them have stethoscopes.

And they are wearing the stethoscope in the exact same way–which is like a shawl around the back of the neck. Andrew Bomback says this way of wearing the stethoscope is a relatively recent fashion trend, probably borrowed from TV shows like ER and Scrubs. Doctors used to wear their stethoscopes dangling down the front of the shirt like a tie, which was practical. If you needed to use it quickly you could just pop it into your ears. Bomback observes that “it’s almost like this new version of wearing it like a scarf or a shawl is almost a concession that it’s more a fashion accessory than actually a tool that we’re using.”

But even if it’s become a fashion accessory, Dr. Bomback isn’t ready to give up his stethoscope. He says it’s an important conduit to connecting with his patients. Physical contact between a doctor and a patient has become increasingly rare. Doctors visits are short and physicians often spend much of time staring at a computer screen. Bomback says the stethoscope provides an important opportunity for intimacy.

“The stethoscope is still a part of the exam” he says, “aligned with the laying on of hands” associated with healers. “When we go to do the physical exam, we move away from our desk, we move away from the computer, and we stand right next to the patient and it’s a much more intimate conversation.”

Bomback says he thinks the stethoscope lives on in part to keep doctors and patients from drifting too far apart. To make sure doctors keep close to their patients, and keep listening.