William Ewart Gye FRS (born William Ewart Bullock; 11 August 1889, Breaston – 14 October 1952) was a British pathologist and cancer researcher.^[1][2][3]

After a difficult financial struggle, Bullock matriculated at University College, Nottingham and, after studying chemistry under Kipping, graduated there with a BSc in 1906.

In 1911, Bullock married his first wife, Elsa Gye, who was a dedicated suffragette.^[4] Bullock studied medicine at the University of Edinburgh and in 1912 graduated there MBChB. In 1913 he received his Doctor of Medicine qualification from the university, and won a gold medal for his medical thesis.^[5] He also won the Ellis Prize in Physiology for his essay, “The chemistry of nerve degeneration.”^[6]

In 1913, he joined the staff of the Imperial Cancer Research Fund,^[2] which at that time was under the direction of Ernest Francis Bashford.^[7] When World War I started, Bullock joined the Royal Army Medical Corps and served in France and then Italy in charge of a field ambulance unit.^[8] He was reassigned to London as a hospital pathologist and worked with William Cramer on gas gangrene.^[9]

After demobilization with the rank of captain, he joined the National Institute for Medical Research at Hampstead, where he worked with Edgar Hartley Kettle on silicosis.^[10] In June 1919,^[11] William Bullock's wife retook her maiden name, and William Ewart Bullock changed his surname to "Gye",^[4] perhaps because he wanted to please his wife^[4] and perhaps because he was irritated by having to often explain that he was not the bacteriologist William Bulloch — there is a theory that the name change was in gratitude to a benefactor (not Bullock's wife or father-in-law).^[12]

With W. J. Purdy, Gye conducted experiments confirming Peyton Rous's claims concerning the Rous sarcoma virus.^[13] Gye was the director of the Imperial Cancer Research Fund's laboratories at Mill Hill from 1934 to 1949, when he resigned due to ill health. He was elected a Fellow of the Royal Society in 1938 and a Fellow of the Royal College of Physicians in 1940.^{[citation needed]}

Gye's and his first wife, Elsa, had three sons together. She died of cancer in 1943. On 30 December 1944,^[14] Gye married ophthalmologist Ida Mann (later Dame Ida Mann) and, in 1949, they moved to Perth, Western Australia.^[8]