History
Psoralens have been known since ancient Egypt but have only been available in a chemically synthesized form since the 1970s.
Read more about this topic: PUVA Therapy
Famous quotes containing the word history:
“The history of all previous societies has been the history of class struggles.”
—Karl Marx (1818–1883)
“At present cats have more purchasing power and influence than the poor of this planet. Accidents of geography and colonial history should no longer determine who gets the fish.”
—Derek Wall (b. 1965)
“You treat world history as a mathematician does mathematics, in which nothing but laws and formulas exist, no reality, no good and evil, no time, no yesterday, no tomorrow, nothing but an eternal, shallow, mathematical present.”
—Hermann Hesse (1877–1962)