Hi, I'm Anna Dhody, Curator at the Mutter Museum and Director of the Mutter Research Institute.
And today, I'd like to talk to you a little bit about the history of the stethoscope.
Before the early 1800s, a visit to the doctor’s office could get…. pretty intimate.
Throughout medical history, doctors used multiple senses to get an idea of what was happening in a person’s body.
Feeling pulses, listening to the heart, even tasting urine at some points.
Hippocrates would even take people by the armpits and shake them around to see if there was any fluid splashing
in their chest . He and his students also practiced immediate auscultation,
where they’d put their ear onto someone’s chest and listen. Did it give them any useful information?
Not really, but it was a start. All of this would change once a French doctor
introduced the world to a small wooden tube — this became the first stethoscope,
and it revolutionized how doctors listen to the body forever.
The idea of a modern physical exam would’ve been completely out of place to a physician in the 1700s.
Physicians would likely ask patients questions and look at the outside of the body.
But all of the stuff causing disease was happening under the patient’s skin,
so aside from cutting them open, they couldn’t do much to observe the problem.
That was, until an Austrian doctor named Leopold Auenbrugger started tapping on people’s chests.
Auenbrugger noticed that if he tapped a human thorax with his fingers, it made different sounds depending on what was inside,
This became known as "percussion." Yes, just like the percussion section for you fellow orchestra nerds.
So he got to work percussing all the human thoraxes he could, making his best guess to
their diseases, and confirming or correcting his guess after they died.
If the chest was filled with liquid, it made a dull, low pitched noise.
If it was normal and healthy, it would be sharp and higher pitched.
Since it was the 1700s, and fluid-filled lungs was a pretty common symptom
back then, he had plenty of opportunities to practice. He wrote all of his observations and
details for percussion in a book titled "Inventum Novum," or "New Invention," and published it in 1761.
And then, just kinda, nothing happened. There was no big clinical medicine revolution, no fanfare, nothing.
For whatever reason, Auenbrugger’s work didn’t really catch on within the German medical community,
That is, until a French doctor named Nicolas Corvisart stumbled upon it.
Corvisart translated Inventum Novem from Latin to French, and started percussing patients in Paris, which is
precisely where the practice became more popular. His translation of Auenbrugger’s book was more of
an adaptation. Corvisart added over 300 pages to the original text, which makes a lot of sense
considering he had another 20 years of percussing to write about. And thank goodness he worked in France!
Back then, Paris was a progressive place to be a physician. See, prior to this time in Europe,
there was a bit of a rift between the more academic, theoretical physicians, and the
more practical, hands-on surgeons. These academics trusted abstract theories over information they
could learn with the senses, like observation or listening. But France was different. Professors at
the Paris Faculty of Medicine often started their careers in surgery, and learned about the body
through direct observation. Corvisart was having none of that abstract stuff. In his preface,
he puts his full trust in the power of observation and bedside manner saying:
And it seems like this stems from Corvisart’s desire to fix errors in medicine.
He’d seen too many mistakes in diagnosis of lung diseases.
Now Corvisart had one student in particular that used the acoustic side of percussion in a cool new way.
Allow us to introduce Rene Laennec. Laennec was born in 1781 and was inspired into medicine after
his mother passed away from tuberculosis. He started his career in Nantes, France and later
moved to Paris, where he studied under Corvisart and learned percussion. Then one day in 1816,
a young woman came into Laennec's office who had some general symptoms of heart disease,
which means he would need to listen to her chest. There was one major problem with that:
it would be socially inappropriate for a man to put his ear on a young woman’s chest.
But some quick creative thinking saved him. Laennec remembered this phenomenon in acoustics:
If you take a plank of wood, and scratch one end of it with a pin, you can hear the scratch on the opposite
side of the plank. So he grabbed a nearby stack of paper, rolled it up into a tight tube,
and put one end on the young woman’s chest and the other end to his ear.
And voila! He could hear a heartbeat! ...sans social taboo.
Not only that, but somehow this DIY sound piece made the heartbeat more distinct.
And that was a big deal. So by September of 1816, he started rolling up sheets of paper into proto-stethoscopes
and told his medical peers in Paris about his invention. Very soon thereafter, doctors throughout Europe adopted this early tool.
Now, a roll of paper isn’t the most professional looking or consistently accurate instrument,
so Laennec started toying around with different designs for a better auscultation tool.
He came up with a wooden tube about 1 foot long and 1.5 inches in diameter
with three detachable parts. He put a little stopper inside to listen to the heart,
but removed it to hear lung sounds. He called this new device the "stethoscope."
"Stethos" meaning chest, "scopos" meaning examination in Greek.
Laennec came out with a big summary of his findings in 1819 titled
"A Treatise on the Diseases of the chest, in which they are described according to their Anatomical
Characters, and their Diagnosis established on a New Principle by means of Acoustic Instruments"
….except in French, which we’re not gonna even try to pronounce here.
In the treatise, or report, he described the new stethoscope, but also detailed what they could do.
After all, it’s probably helpful to know what these different sounds meant if you were a doctor listening to the lungs.
He divided the normal sounds into pulmonary and bronchial sounds, and abnormal sounds, which he called "adventitious" sounds.
And some of them have familiar names like gurgling, crackling, whistling, and snoring.
Some of these descriptions were brand new for the time, like rales, fremitus,
egophony and bronchophony, bruits, and veiled puffs. We’re not making this up.
And Laennec was obsessed with matching these abnormal sounds to the diseases in a patient’s lungs.
Given how common lung disease was back then, he had plenty of opportunities to listen to someone’s lungs,
make a diagnosis, then perform an autopsy when they died — which was often. Laennec was particularly
interested in studying tuberculosis, or what they would’ve called "consumption."
During autopsy, he noticed that some tuberculosis patients’ lungs were filled with fluid or pus, which explained
some of those lung sounds. This helped him build a clinical description of tuberculosis,
including what a doctor should listen for when diagnosing it. But that didn’t really help him treat TB.
We wouldn’t get a useful remedy for tuberculosis until 1854, and that remedy was
basically fresh air and rest. Laennec didn’t just listen to the lungs. He used the stethoscope to
listen to the heart, and correctly matched heart sounds to the contraction of different chambers of the heart.
Unfortunately, we just didn’t know that much about heart physiology back then,
so it was tricky to use the stethoscope in the evaluation of heart disease. His book was received
mostly positively with the Quarterly Journal of Foreign Medicine and Surgery claiming that:
And at the practical level, his book was huge for the medical community at the time.
Doctors all over the world started experimenting with it in their own practices and wrote about their findings.
Laennec himself died of tuberculosis in 1826, very proud of his device.
And while it was great progress, the first iteration of the stethoscope posed some tricky challenges.
For instance, doctors would love to listen to their own lungs, which is impossible with a straight wooden cylinder.
So a few years after Laennec's invention, doctors started experimenting with flexible instruments made out of
coiled metal wire wrapped in silk. But as more people started using the stethoscope,
different doctors would tweak it into a more user-friendly form. The first binaural stethoscope, or device that went in both ears,
came in 1829. But it wouldn’t get a rubber hose or rubber ear caps until mid-century,
when rubber was finally durable enough to be molded in that kind of shape.
These days, doctors still use stethoscopes, but more precise and accurate diagnostic tools exist.
Listening to the lungs is great, but taking images with X-rays or MRI has helped a ton.
While that first Laennec stethoscope was groundbreaking from a technical perspective,
it also represents a shift in how doctors learned about patients’ bodies. Diagnoses shifted towards
a more hands-on, physical approach that would make a lasting impact on modern medicine.
If you want to see some of these first stethoscopes, then come visit us,
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