History
Psoralens have been known since ancient Egypt but have only been available in a chemically synthesized form since the 1970s.
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Famous quotes containing the word history:
“It is remarkable how closely the history of the apple tree is connected with that of man.”
—Henry David Thoreau (1817–1862)
“The history of every country begins in the heart of a man or a woman.”
—Willa Cather (1876–1947)
“Culture, the acquainting ourselves with the best that has been known and said in the world, and thus with the history of the human spirit.”
—Matthew Arnold (1822–1888)