Lt Col Henry Osborne MacCabe Merewether was educated at Geelong, Sydney University, and at Edinburgh University, where he graduated MB, ChB in 1931. After graduation he became house-surgeon to Sir David Wilkie, and, later, senior house-surgeon at the Leicester Royal Infirmary.
In 1936, he was elected a Fellow of the Royal College of Surgeons of Edinburgh., The following year, he entered into a surgical partnership with Mr H W L Molesworth in Folkestone, and in 1938, was appointed surgeon to the Royal Victoria Hospital.
In 1939, at the outbreak of the second world war, he was commissioned into the RAMC as a surgical specialist. He served with distinction until 1945, having become a lieutenant colonel in charge of a surgical division. He saw service in Eritrea, Malta, and Italy, and was appointed OBE in 1945 for his services during the Italian campaign. Just after the end of the war he underwent a serious operation, but, in spite of severe physical handicap, returned to his work as a surgeon. He became senior consulting surgeon to the hospitals in the South-East Kent Group, and was actively engaged in consulting practice until a few days before his death.