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:
“History, as an entirety, could only exist in the eyes of an observer outside it and outside the world. History only exists, in the final analysis, for God.”
—Albert Camus (1913–1960)
“American time has stretched around the world. It has become the dominant tempo of modern history, especially of the history of Europe.”
—Harold Rosenberg (1906–1978)
“A man will not need to study history to find out what is best for his own culture.”
—Henry David Thoreau (1817–1862)