Today on the Google home page in the U.S. is a special Doodle, aka Google logo, for the 115th birthday of the late Percy Lavon Julian.
Born today on April 11, 1899, he lived until 8 days after his 76th birthday, passing on April 19, 1975 in Waukegan, Illinois.
Percy Lavon Julian was one of the first African-Americans to receive a doctorate in chemistry and is known for his breakthroughs in the field of chemistry.
Specifically he was a "pioneer" in the chemical synthesis of medicinal drugs from plants. He was the first to synthesize the natural product physostigmine and to synthesize human hormones progesterone and testosterone from plant sterols.
Percy Lavon Julian's grandfather was a slave and he himself grew up in a terribly racist time. You can learn more about his life on Wikipedia.
Forum discussion at Google+.