Penicillin nontoxic in humans by first performing toxicity tests in animals and then on humans. His subsequent experiments on penicillin's response to heat and pH allowed Fleming to increase the stability of the compound. The one test that modern scientists would find missing from his work was the test of penicillin on an infected animal, the results of which would likely have sparked great interest in penicillin and sped its development by almost a decade. The importance of his work has been recognized by the placement of an International Historic Chemical Landmark at the Alexander Fleming Laboratory Museum in London on
Joan S. Valentine Joan S. Valentine Joan Selverstone Valentine (born 1945) is a biological inorganic chemist and biochemist. Valentine's current work examines the role of transition metals, metalloenzymes, and oxidative stress in health. Her foremost expertise is superoxide anion and its functional enzyme superoxide dismutase. Valentine has been a member of the faculty of the University of California, Los Angeles since 1980, she has served as Editor-in-Chief of "Accounts of Chemical Research" since 1994, and she was elected to the National Academy of Sciences in 2005. In 1967, she graduated with a Bachelor of Arts in Chemistry from Smith College and a Ph.D.