Henrik Carl Peter Dam (1895-1976) was awarded half of the 1943 Nobel Prize in Physiology or Medicine for his discovery of vitamin K. He discovered the vitamin while studying the sterol metabolism in chicks. After feeding them a cholesterol-free diet, he noticed hemorrhaging and uncontrollable bleeding. He then isolated the dietary substance required for blood clotting and called it Koagulations Vitamin (meaning "coagulation vitamin" in Danish), which was shortened to vitamin K. He later showed this antihemorrhagic vitamin to be fat-soluble and present in green leaves. Dam was also able to isolate the vitamin from alfalfa. In addition to vitamin K and cholesterol, he also studied vitamin E, fats, and gall-stone formation.