Marguerite Davis is best known as co-discoverer of vitamins A and B. Her research at the University of Wisconsin in Madison with biochemist Elmer Verner McCollum led to definitive identification of both vitamins and paved the way for later research in nutrition.

Davis was born on September 16, 1887, in Racine, Wisconsin. Her father, Jefferson J. Davis, was a physician and botanist who taught at the University of Wisconsin. Her grandmother, Amy Davis Winship, was a social worker and an early champion of women's rights. Her background, coupled with her own interest in science, led her to enroll at the University of Wisconsin in 1906. She transferred to the University of California at Berkeley in 1908 and received her bachelor of science degree there in 1910. Upon graduation, she returned to the University of Wisconsin and pursued graduate studies, although she never completed the master's program. She worked briefly for the Squibbs Pharmaceutical...