Thompson, Sir William Henry (1860–1918), physiologist and author, was born 17 August 1860, third son of William Thompson of Ballynulty House, near Granard, Co. Longford, and grandson of Robert Thompson of Cloncoose, Co. Longford; his mother's name is not known. Educated at the Dundalk Institution, he entered QCG in 1879, where he studied medicine. His university career was distinguished: he won the QUI Peel prize in mathematics, came first in his medical examinations for four years (1880–83), and graduated with first-class honours in 1883. In 1885 he won a special prize and diploma for his study of mental diseases, and was appointed as a demonstrator of anatomy at TCD (1887–91). He later travelled abroad, carrying out further studies in London, Leipzig, Paris, Marburg, and Heidelberg.
In 1893 he became the first Dunville professor of physiology at QCB. Under the terms of the foundation of this professorship, he was obliged to give a course of public lectures on the subject of hygiene, and delivered his first series in 1893. They were attended by large crowds, and soon became a popular feature of the college's lecture year. In 1899 he was elected an honorary member of the Imperial Military Academy of Medicine in Petrograd. Appointed as an examiner in physiology by the Royal University of Ireland (1900–02), in 1902 he was appointed as King's professor of the Institutes of Medicine at the School of Physic in TCD, succeeding John Mallet Purser (qv). A renowned authority on dietetics, he published a translation of I. P. Pavlov's The work of the digestive glands (1904). He also published numerous papers in the Journal of the British Association, Journal of Physiology, British Medical Journal, and Archives de Physiologie Normale et Pathologique. In 1904 he was awarded an honorary doctorate by TCD. He was also a fellow of the RCPI and of the Royal College of Surgeons in England, resigning from the latter in 1914.
In 1914 he was appointed as scientific advisor to the ministry of food, subsequently publishing Food values, with a note on Irish food supplies (1917). He was awarded a KBE in 1918. His work for the ministry made it necessary for him to make frequent trips to London and, on the morning of 10 October 1918, he embarked on the mailboat RMS Leinster in Kingstown (Dún Laoghaire) harbour. At around 10 a.m. the Leinster was torpedoed in the Irish Sea by a German U-boat and Thompson was one of the 501 fatal casualties of the sinking.
He married (1894) Isabel Redfern, eldest daughter of Prof. Peter Redfern of QCB. They had one son and four daughters. In 1935 Lady Thompson presented TCD with a portrait of her late husband. Their Dublin residence was at 14 Hatch St.