“Sunbathing! The twelve effects of sunlight on the skin: (1) skin reddening, (2) skin tanning, (3) disinfection, (4) immunization, (5) higher blood pressure, (6) stimulation of scavenger cells, (7) increase in tone, (8) vitamin D, (9) cell radiation, (10) the charging of the nervous system, (11) the light hormone, (12) the luminous element porphyrin.” *NOTE: Kahn included the observation of the worsening of scarring in smallpox patients under his section on porphyrins (12) noting that both smallpox patients and people that have been cutaneously injected with hematoporphyrin exhibit photosensitivity. CAPTION OF ILLUSTRATION FROM VOLUME II OF GERMAN PHYSICIAN FRITZ KAHN'S DER MENSCH GESUND UND KRANK, MENSCHENKUNDE, PUBLISHED IN 1939. IMAGE COURTESY OF THE NATIONAL LIBRARY OF MEDICINE
Around the turn of the 20th century—before sunscreens hit the market and the damaging effects of UV radiation were widely appreciated—physicians saw the sun mostly as a source of healing. Sunlit spas nestled high in the mountains became very popular among those who could afford them, and color lamps for treating a variety of illnesses were common fixtures in many rooms. Experiments on microorganisms, animals, and even humans revealed all sorts of beneficial effects of sunlight, many of which are still recognized and appreciated, such as enhanced immune function, improved musculature, and even a banishment of the blues.
(3) In 1903, physician Niels Ryberg Finsen received the third Nobel Prize awarded in physiology or medicine for demonstrating that exposure to the sun’s ultraviolet (UV) rays ...
