He was born on 23 June 1892 at Christiania, son of Dr Peter F Holst (1861-1935), professor of internal medicine at the University, and a descendant of Frederick Holst MD (1791-1871) of whom he afterwards wrote a memoir. J M Holst won a scholarship to the University of Oslo, as the city was called after the separation of Norway from Sweden in 1905, and served at the University Clinics and Pathological Anatomy Institute, at Ullevaal Hospital and at the Oramnien General Hospital. In 1918 he led a Norwegian ambulance unit in Finland during the war of liberation, and again in 1939 he went on a similar expedition. He took the MD degree in 1923, was appointed assistant surgeon in the State Hospital, becoming senior assistant in the surgical division and surgeon to the first University Clinic in the Hospital in 1930. The same year he was elected professor of surgery in succession to Johan Nicolaysen, Hon FRCS. Holst was at first drawn to the surgery of goitre; then he devoted himself to improving the operative treatment of cancer, especially the ablation of gastric cancer, for which he was one of the early advocates of a thoracoabdominal approach. But he made most mark in developing the surgery of tuberculous disease of the lung, initiated in Norway by Peter Bull, Hon FRCS Holst published valuable accounts of his work, in Norwegian, German, or English. Early in 1940, when war threatened Norway, he was recalled from the Finland campaign to reorganise the medical services of the Norwegian forces. After Norway had been completely overrun by the Germans he continued for a time to work "underground". Finally escaping to Scotland in dramatic circumstances, as his son too escaped, he was appointed Director-General of the Norwegian Army Medical Services in Iceland and Britain, attached to the 52nd Allied Division. He moved frequently to the scattered positions of his command, and was often in forays on the Continent. During these years 1940-45 he cemented his friendships with leading British surgeons. In 1945 he resumed his university and hospital appointments at Oslo. He served as President of the Norwegian Medical Association, and was elected a member of the Academy of Sciences at Oslo in 1936. He was created a Commander of the Royal Order of St Olaf of Norway. He was an Honorary Fellow of the Royal Society of Medicine, London, and a corresponding member of the Académie de Chirurgie, Paris, and of the Swedish and Finnish Medical Societies. He was elected an Honorary Fellow of the College in 1943, at the centenary of the foundation of the Fellowship. Holst died at Oslo on 17 February 1953 aged 60, of myeloblastic leukaemia, survived by his wife and son. He was a generous host to British surgeons at his home, Gablesgate 46, and at his country house on an island in the bay. His favourite recreation was to explore the fjords and snowfields of Norway, alone; for he had a mystical love of wild nature. He was a generous-hearted man of fine physique, keen intellect, and noble character. Principal Publications: Pathogenetic foundations of iodine therapy of thyrotoxicoses. *Amer J Surg* 19 29 7, 39. Local selective thoracoplasty. *Acta chir scand* 1932, 71, 396 and 1934, 74, 477. Surgical treatment of pulmonary tuberculosis. *Acta chir scand* 1935, Supp. 37; 136 pages. Twenty years experience with surgical treatment of pulmonary tuberculosis. *Edin med J* 1951, 58, 349.