1986 - Edward Adelbert Doisy died.

Todd Helmenstine

Doisy was an American biochemist who was awarded half the 1943 Nobel Prize in Medicine for the discovery of the chemistry of vitamin K. Vitamin K was discovered by Henrik Dam, who received the other half the the Nobel Prize, and Doisy isolated two different forms of the vitamin, determined their structures and synthesized them. Vitamin K is used in surgery and medicine to promote blood clotting. Doisy also isolated the sex hormones estrone, estriol, and estradiol.