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By Jack Mitchell on

The therapeutic benefits of sunlight

Jack Mitchell, the Science Museum's Assistant Curator of Medicine, takes his cue from the summertime and explores the Sun's great influence in the history of medicine.

The summer holidays are now in full flow, and many people will be looking to top up their tans and bronze their skin at some point during their vacation. The health messages we receive about being skin and sun aware are well established, and for good reason we should all display caution when out in the sun in order to reduce the risks of developing skin cancer.

It may then surprise you to know that in early 20th century Europe sunlight was in fact being heralded as a new, progressive medical therapy that had numerous positive health benefits. Whether it was via natural means- Heliotherapy– or via artificial methods- Phototherapy– the medical profession held up light as a powerful and triumphant form of treatment.

Silhouette of a nude woman leaping in a sunburst © Wellcome Library, London
Silhouette of a nude woman leaping in a sunburst © Wellcome Library, London

The curative potential of light and its discovery as a revolutionary “new” treatment had its foundations in the pioneering work of 19th century bacteriologists such as Arthur Downes, Thomas Blunt and Robert Koch. Their published works demonstrated the antibacterial properties of light, and as such opened up the field of light therapeutics as a scientifically justified and potentially ground-breaking area of medical treatment.

The ability of light to destroy tuberculosis bacillus, and potentially aid in the treatment of illnesses such as lupus and pulmonary tuberculosis was a particularly exciting medical discovery, especially considering the prevalence of the disease within contemporary industrialised society, and its resistance to most forms of treatment.

Front cover for booklet advertising Peps tablets © Wellcome Library, London
Front cover for booklet advertising Peps tablets © Wellcome Library, London

However, the increased medicalisation of light and its transfer from a handful of specifically located, sun drenched, natural sanatoriums (heliotherapy), to the automated and controlled arena of a hospital, relied heavily on the ability to artificially harness UV rays (phototherapy). This was achieved thanks to the pioneering work of Danish physician Neils Ryberg Finsen, who in 1894 developed his eponymous lamp for the treatment of tuberculosis of the skin (lupus vulgaris).

Plate LXVI, Lupus vulgaris from Prince Albert Morrow, 1889 © Wellcome Library, London
Plate LXVI, Lupus vulgaris from Prince Albert Morrow, 1889 © Wellcome Library, London

Alongside the physical development of the apparatus, Finsen opened a Medical Light Institute in Copenhagen, which researched the impact of the therapy and the efficacy of light as a treatment in general. The institute was part funded by the Danish state; a symbol of the importance placed upon this new therapy and how readily it was accepted as a progressive new treatment with significant medical potential.

Finsen’s lamp used telescopic arms to mimic the beneficial effects of the sun and focus the remedial properties of UV light onto an infected area of skin. His process achieved remarkable results and earned him worldwide notoriety, including the support and patronage of fellow Dane, Queen Alexandra, wife of Edward VII, whilst she was Princess of Wales. Alexandra presented a lamp to the London Hospital in 1900, and thus helped establish a light therapy department within the UK. This lamp is now part of the Science Museum’s collection. Finsen’s work was further recognised in 1903, when he was awarded the Nobel Prize for Medicine.

Set of apparatus devised by N.R. Finsen for treating lupus © Wellcome Library, London
Set of apparatus devised by N.R. Finsen for treating lupus © Wellcome Library, London

Finsen’s ground-breaking work, and the positive results it achieved in treating tuberculosis of the skin, did much to sow the seeds for light therapies acceptance within both medical and popular society, and solidify its reception as a regenerative medical cure. The zenith of light therapies popularity came in the 1920’s/30’s, when numerous tanning apparatus’ were sold to the domestic market in a heavily glamorized manner.

A 'Homesun' solarium advertisement, 1939 © Science Museum / SSPL
A ‘Homesun’ solarium advertisement, 1939 © Science Museum / SSPL
Leaflet for the "Vi-Tan" ultra-violet home unit © Wellcome Library, London
Leaflet for the “Vi-Tan” ultra-violet home unit © Wellcome Library, London

Upon being awarded his Nobel Prize, it was commented that Finsen deserved the “eternal gratitude of suffering humanity”, yet his lamp was gradually phased out upon the discovery of antibiotics. Although light therapy is still used today, notably for the treatment of Seasonal Affective Disorder, the negative impact of excess UV light on skin creates a challenging tension with its notion as a universally healing force. A very ambiguous impression of light within a medical sphere therefore emerges; to one which simultaneously emphasises its benefits, whilst also warning us of the deleterious effects of over exposure.

Jack Mitchell, the Science Museum’s Assistant Curator of Medicine, takes his cue from the summertime and explored the Sun’s great influence in the history of medicine.