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The invention of the stethoscope

This year is the two hundredth anniversary of the invention of the stethoscope. Incredibly, today’s symbol of medical professionalism began life as a sheet of paper used to protect a young lady’s modesty.

Two hundred years ago, medicine was practised very differently from today. While many doctors enjoyed some formal education, their knowledge of human physiology was decidedly patchy. Anatomy was perhaps a little better understood, particularly where there was access to cadavers for study.

In part, development of most branches of medicine was also held back by social attitudes and conventions. Today there may still be a moment of awkward embarrassment when discussing some aspects of the body with a patient. Two hundred years ago, the importance attached to privacy could prevent physicians making proper examinations.

Plaque at Hopital Necker commemorating Laennec's discovery. Luca Borghi, Wikimedia
Plaque at Hopital Necker commemorating Laennec’s discovery. Luca Borghi, Wikimedia

Modesty prompts medical innovation

In 1816, a 35 year old French doctor, René Laennec, was presented with what he later described as an overweight young lady with ‘general symptoms of diseased heart’. Laennec had recently been appointed chief physician at Hôpital Necker, in Paris.

His medical training had included using the sounds of the body as a diagnostic method. However, in this case, the ‘age and sex of the patient’, along with her ‘great degree of fatness’ made the usual practice of putting the ear to the patient’s chest both inappropriate and ineffective.

Three years later he wrote down what happened next. “I happened to recollect a simple and well-known fact in acoustics… the great distinctness with which we hear the scratch of a pin at one end of a piece of wood on applying our ear to the other. Immediately, on this suggestion, I rolled a quire of paper into a kind of cylinder and applied one end of it to the region of the heart and the other to my ear, and was not a little surprised and pleased to find that I could thereby perceive the action of the heart in a manner much more clear and distinct than I had ever been able to do by the immediate application of my ear.”

With that flash of inspiration, the principle of auscultation was established.

From quire of paper to medical instrument

Laennec didn’t continue using rolls of paper as part of his diagnostic technique for very long. Believing his discovery to be a significant advance in medical practice, he dedicated a huge amount of time to developing his new technique for diagnosis.

He experimented with different materials to discover which would be most suitable for a more robust device. Glass and metal were rejected, along with a lightweight funnel made from goldbeater’s skin – animal membrane used to create a fine parchment.

Laennec’s first satisfactory instrument, which he called a stethoscope, was a wooden cylinder about 30cm long and hollowed out into a funnel shape. He was very particular about the dimensions, having established these as giving the best results.

You can see Laennec’s original stethoscope in the Science Museum, London.

Laennec’s original stethscope. The Science Museum, London

The stethoscope provokes ridicule and resistance

As with so many innovations, not everyone immediately recognised the potential of the stethoscope.

In 1818, Laennec introduced his discovery to the French medical establishment by giving a talk at the Academy of Sciences. The following year he published details of the stethoscope and its role in diagnosis in his book ‘De l’auscultation médiate’.

Some distrusted the notion of using a tube to improve diagnosis, while others openly mocked it. Had his book focused entirely on the instrument, it may have been overlooked, but it also included detailed and valuable descriptions of diseases of the chest. Laennec documented details of specific cases, describing the symptoms observed in a patient and his subsequent findings during dissection after death.

Younger members of the medical profession in Paris responded more positively to Laennec’s ideas about using a stethoscope. Their enthusiasm helped spread the word across Europe over the next few years.

The sad fate of the inventor of the stethoscope

Having spent some years away from Paris, writing his book, Laennec returned in 1821 to continue his work at Hôpital Necker. He was soon appointed Chair of Medicine in the College of France and then Professor of Clinical Medicine.

While he lectured and wrote, medical practitioners from across Europe came to Paris in order to learn about the stethoscope and to meet its creator.

Laennec had never enjoyed good health and in early 1826 his condition deteriorated. In an ironic twist, the inventor of the stethoscope, one of modern medicine’s most valued tools, was subjected to medieval medical treatments including bloodletting. He died of tuberculosis on 13 August 1826.