Project GutenbergAmerican biochemist Florence Seibert died #OTD in 1991.
At age three, Florence contracted polio. She had to wear leg braces and walked with a limp throughout her life. She is best known for identifying the active agent in the antigen tuberculin as a protein, and subsequently for isolating a pure form of tuberculin, purified protein derivative (PPD), enabling the development and use of a reliable TB test.
