Edwin B. Hart

Edwin Bret Hart (December 25, 1874 – March 12, 1953) was an American biochemist long associated with the University of Wisconsin-Madison.

A native of Sandusky, Ohio, Hart studied physiological chemistry in Germany under Albrecht Kossel (recipient of the 1910 Nobel Prize in Physiology or Medicine) at the University of Marburg and University of Heidelberg. Upon his return to the United States, he worked at the New York State Agricultural Experiment Station (part of Cornell University) in Geneva, New York, and then at the University of Michigan before being hired in 1906 by Stephen M. Babcock of the University of Wisconsin to conduct what later came to be known as the "single-grain experiment", which ran from May 1907 to 1911. This experiment entailed a long-term feeding plan using a chemically balanced diet of carbohydrates, fat, and protein instead of single-plant rations as done in Babcock's earlier experiments of 1881 and 1901.

Hart directed the experiment, Babcock provided ideas, and George C. Humphrey oversaw the welfare of the cattle during the experiment. Elmer Verner McCollum, an organic chemist from Connecticut, was hired by Hart to analyze the grain rations and the cow feces. The experiment called for four groups of four heifer calves each, of which three groups were raised and two pregnancies were carried through. The first group ate only wheat, the second group ate only bran, the third group ate only corn, and the last group ate a mixture of the three.

In 1908, it was shown that the corn-fed animals were the most healthy of the group while the wheat-fed groups were the least healthy. All four groups bred during that year, with the corn-fed calves being the healthiest while the wheat and mixed-fed calves were stillborn or later died.