By Anne Locker
The development of electricity for medical therapy and devices dates back to the beginnings of the science of electromagnetism and the beginnings of modern medicine.
In 1791, Luigi Galvani discovered the role electricity plays in the body – at first, by twitching frogs’ legs – a phenomenon he called ‘animal electricity’. His fellow scientist Alessandro Volta built on Galvani’s work (although he disagreed with the nature of electricity) and developed the first electric battery in 1800, which meant an electric current could be easily produced for further experimentation and research. Michael Faraday’s description of a ‘dark space’ around the cathode in his electrical experiments led to the discovery of X-rays by Wilhelm Roentgen in 1895, and the development of the telephone led to the first electric hearing aids.
Other new electrical technology was used for therapeutic purposes. The electric arc lamp was developed in the early 19th century, and Thomas Edison and Joseph Swan demonstrated incandescent (filament) lamps in 1879. As well as lighting our homes and streets, these new electric lamps were used for phototherapy, as described in advertising pamphlets from the IET’s rare books collection.
The large collection of contemporary pamphlets collected by Silvanus P Thompson, now in the IET Archives, contains two volumes on ‘Electrophysiology’, including advertisements for early electro-therapeutic equipment. One pamphlet describes Sanitas ‘light baths’ – basically, a wooden box (shaped more like a shower than a bath) lit with electric lamps.
The Sanitas Company made two models of the light bath. The first was a cabinet with a hinged door, lit by 6 incandescent lamps. The cabinet was lined with white majolica (a kind of glazed pottery) which reflected the light from the lamps onto the occupant. It was marketed as a modern Turkish bath that could cure all ills.
The second model used arc lamps. Arc lamps were usually considered unsuitable for indoor use as they gave off white-hot sparks, and the company warned against ‘suspending arc-lamps, free and unprotected, in the interior of the apparatus, as the particles of incandescent carbon … inflict very painful burns.’ Instead, the arc lamps were placed at the sides (although still in a wooden box), ‘arranged in such a way that no loose pieces of burning carbon can find their way into the bath.’
The company also made a combination ‘double-light’ bath – a cabinet with incandescent lamps, and a separate arc lamp projector which could be shone on a specific area of the body. There was an option to add coloured screens to filter the light. As these were made of asbestos, they did not add to the overall safety of the apparatus.
The Sanitas company claimed that light baths could be used to treat a wide range of health conditions, from lupus to cholera and from diabetes to heart disease. But these claims were not backed with compelling evidence, and phototherapy soon fell out of fashion in medicine. Today, we have rediscovered the importance of light exposure for the body and mind, and use daylight-spectrum lamps to help treat seasonal affective disorder (SAD). No arc lamps or majolica panels required!