Many historical studies of blind people have focused on their contribution to touch-sensation reading and writing technologies, such as those developed by Louis Braille. However, in the 18th and 19th centuries, the blind also played an important role in the development of acoustic medical technologies – such as the stethoscope or techniques of musical therapy. Many may have been of questionable value, but others survive today.

Now, a Wellcome-funded research project is, for the first time, examining the historical relationship between blindness, sound and medicine.

“The whole culture of 19th-century France was infused with sound,” says Ingrid Sykes, a keen organist and the researcher behind the new study. Though little studied to date, theories of sound and music had a great impact on the medical establishment at that time.

“Louis Braille himself was an organist and was greatly influenced by the acoustical theories of the period,” says Dr Sykes, who starts her project at the University of Warwick in Coventry this autumn.

Dr Sykes will examine how two of France’s largest institutes for the blind – the Hospice des Quinze Vingts and the Institute of the Young Blind, both in Paris – used unconventional sound therapies to ‘treat’ the blind. These hospitals were ‘surveillance institutions’ or asylums used to control or imprison blind people, who were typically regarded as defective or deviant.

Following the mapping of the acoustical sine wave in TK, some medical theorists believed that sound could be used to treat or diagnose certain medical conditions and disabilities. (The acoustical sine wave is a graphical and mathematical depiction of the variation in air pressure as a sound is produced.)

The phenomenon generated great excitement among France’s intellectual community during the 18th and 19th centuries, and led to the development of a range of oddball theories – not least the idea that certain types of music could be inherently good (or bad) for the body.

Good (regularly shaped) sound waves “were thought to create a more even effect on the nervous and fluid systems of the body,” says Dr Sykes. Bad waves, on the other hand, “were thought to create a ‘tempestuous’ bodily state.”

On this basis, certain types of music (i.e. music with a functional harmonic system behind it, such as that composed by the classical masters) were believed to be able to heal patients from specific illnesses, mental health problems and disabilities.

The blind patients (thought to be particularly sensitive to sound) were used as guinea pigs to test these theories. They were extensively tutored to play musical pieces of the ‘healthy’ kind, and many became highly proficient musicians.

The language of music was thought to provide an alternative and symbolic way of visualising things. Music became a vital part of these people’s lives; “sonic education became a kind of substitute for lack of vision,” says Dr Sykes.

The theory that acoustical impulses of the body could be graphically mapped and categorised as good or bad was central to major medical discoveries of the period. Particularly notable was René Laennec’s development of the stethoscope, used to listen to sounds within a patient’s body. Laennec even tried to notate musically the sound of the human heartbeat.

The new field of auscultation (diagnosis with sound) in the 19th century was a big shift from the 18th century when vision alone was used to diagnose, says Dr Sykes. Other machines were developed to listen to the fluids in the inner ear and the larynx. Such innovations are, perhaps, the spiritual forebears of today’s non-invasive imaging techniques, such as ultrasound.