William Thornton Mustard OC MBE (August 8, 1914 – December 11, 1987) was a Canadian physician and cardiac surgeon.
In 1949, he was one of the first to perform open-heart surgery using a mechanical heart pump and biological lung on a dog at the Banting Institute.
During World War II, he pioneered an operation that helped keep a patient's limb with severe artery damage rather than amputating it.
In 1944, he performed an operation on a leg of a soldier[4] which would later be recognized with being made a Member of the Military Division of the Order of the British Empire.
[4] In 1976, he was made an Officer of the Order of Canada "in recognition of his many achievements in the field of medicine, particularly as a cardiac surgeon of international repute".