William Parry Murphy (1892-1987) was an American physician and medical researcher. In 1924, Murphy bled dogs to make them anemic and then fed them various substances to gauge their improvement. He discovered that ingesting large amounts of liver seemed to restore anemia more quickly of all foods. Minot and Whipple then set about to chemically isolate the curative substance. These investigations showed that iron in the liver was responsible for curing anemia from bleeding. The active ingredient was not iron, but a water-soluble extract containing a new substance. From this extract, chemists were able to isolate vitamin B12 from the liver. The knowledge that raw liver and its extracts treated pernicious anemia (previously a terminal disease) was a major advance in medicine. He died at the age of 95.