Richard William Morrison Mettam, veterinary pathologist, was the son of A.E. Mettam, principal of the Veterinary College at Dublin, Ireland. He qualified (MRCVS, Dublin) in July 1917 and during the last year of World War I (1914-1918) served in the Army in France, Belgium and Germany. He came to the Onderstepoort Veterinary Research Institute, South Africa, in 1919 and did some teaching in veterinary anatomy at the University College, Johannesburg (later the University of the Witwatersrand) and at the Transvaal University College, Pretoria. In 1922 he was appointed professor and head of the newly created Department of Veterinary Anatomy at the University of the Witwatersrand. The next year he received the MSc degree in zoology at the same university for his thesis, Snotziekte: a disease of South African cattle. His department, which was associated with the Medical School, was closed towards the end of 1924 and Mettam transferred to the Veterinary Faculty of the Transvaal University College at Onderstepoort. During 1923-1926 he published seven papers in quick succession in the South African Journal of Science, in which he described various anatomical abnormalities in the ox and horse.
Mettam left South Africa early in 1927 for Kabete, Kenya to take up an appointment as veterinary reseach officer. Early in 1930 he moved to Entebbe, Uganda, as veterinary pathologist to the Ugandan government and worked on the veterinary toxicology of East African plants. He transferred to Vom in Nigeria in September 1937. His publications during these years included the following: Poisonous plants of East Africa (1930); "Some poisonous plants of Kenya" (Veterinary Journal, 1933); "Turning sickness, a protozoan encephalitis of cattle in Uganda" (with J. Carmichael; Parasitology, 1936); "A short history of rinderpest with special reference to Africa" (Uganda Journal, 1937); and "Experiments on the transmission of Bovine Contageous Pleuro-pneumonia" (Journal of Comparative Pathology and Therepeutics, 1939). In 1950 he was awarded the Order of the British Empire (OBE), but became ill and returned to Britain, where he died soon afterwards.