John Mitchell Watt, physician, pharmacologist and toxicologist, was the son of Scottish parents John Watt and his wife Margaret, born Mitchell. Though born in South Africa he regarded himself as a native of Scotland. He received his schooling initially in South Africa, then moved with his parents to Stirling, Scotland, and finally settled in Cape Town, where he matriculated through the University of the Cape of Good Hope in 1910. Continuing his studies in Edinburgh, Scotland, he graduated in medicine (M.B., Ch.B.) in 1916. Meanwhile he had joined the Edinburgh University Officers' Training Course in 1911, was commissioned in the Royal Army Medical Corps in 1914 and during World War I (1914-1918) was on active duty for three and a half years in the Middle East, India and Russia, rising to the rank of major in 1919. Returning to the University of Edinburgh in 1920 he joined the Department of Materia Medica for the 1920/1921 session. He was then appointed as the first professor of pharmacology and therapeutics in the newly established Medical School of the University College, Johannesburg (from 1922 the University of the Witwatersrand) assuming duty in June 1921. He remained in this post until his retirement at the end of 1957. In September 1922 he was elected dean of the Faculty of Medicine, serving in this capacity to March 1925. He served as senate's representative on the university council from 1922 to 1925 and again from 1930 to 1938. During 1927-1928 he spent some time at the University of München. When the South African Medical Council was constituted in 1928 he became the university's first representative on the council. He qualified as a Fellow of the Royal College of Physicians of Edinburgh in 1948. During World War II (1939-1945) he served in the South African Medical Corps and was placed in charge of medical supplies at South African Defence Headquarters for four years. In 1945 he was awarded the Efficiency Decoration and the Chief of Staff's Certificate of Commendation for Outstanding War Service. In 1953 he retired from the Union Defence Force with the rank of colonel. Upon his return to the university after the war he served as dean of the Faculty of Medicine for another three years.
Watt conducted extensive research in pharmacology and toxicology and paid particular attention to indigenous plants with medicinal or poisonous properties. His most important publication is his book, written in collaboration with Dr M. Breyer-Brandwijk, The medicinal and poisonous plants of southern Africa, being an account of their medicinal uses, chemical composition, pharmacological effects and toxicology (1932). An augmented second edition was published as The medicinal and poisonous plants of southern and eastern Africa in 1962. This was a classic work and an outstanding achievement which gained its authors an international reputation. In addition he published dozens of papers and reports on topics such as allergic disorders, poisons, and indigenous medical practice. For example, Suto (Basuto) medicines (with Breyer-Brandwijk, 1928, 319 p); "The medicines and practice of a Sotho doctor" (with N. J. van Warmelo, Bantu Studies, 1930) and "The forensic and sociological aspects of the dagga problem in South Africa" (with Breyer-Brandwijk, South African Medical Journal, 1936).
In recognition of his scientific contributions Watt was elected a Fellow of the Royal Society of South Africa in 1933 and a Fellow of the Royal Society of Edinburgh in 1934. He was president of the South African Arboricultural Society for nine years. He collected some 3500 South African plant specimens over the years, which are housed in the National Herbarium, Pretoria, and the Moss Herbarium of the University of the Witwatersrand.
For many years Watt played an important role in the St John Ambulance Brigade and rose to priory surgeon-in-chief of southern Africa. He was awarded the Brigade's Long Service Medal (1945) and the Order of St John of Jerusalem in the rank of commander (1948).
After his retirement Watt lectured for some time at the Plymouth College of Technology in England and worked at the South African Institute for Medical Research until 1965. He then moved to Brisbane, Australia, where he became a part-time demonstrator in the Department of Physiology (including pharmacology) of the University of Queensland, a position he held until his death in 1980. He continued his research and publication, his last significant publication being a paper on "Anaphylactic reactions after use of CT 1341 (althesin)" in the British Medical Journal (1975).
Watt never forgot his Scottish background and often wore a kilt at functions. He has been described as a very pleasant person, if a little pompous, and took a keen interest in student affairs (Murray, 1982). In 1920 he married Yelena Timofeyevna Nikonova in Baku, Russia. They were divorced in 1942 and that same year he married Betty Gwendoline Lory. He was survived by three sons and two daughters.
