Born on 28 May 1865 at Colchester, the second child and only son of Thomas Mothersole, a wine merchant, and his wife Esther Cooke. He was educated at Framlingham College, and took the Conjoint qualification in 1888 from Guy's Hospital. He took the London MB BS the next year with first-class honours, and proceeded to the Fellowship in 1890. He was house surgeon at Guy's, and senior house surgeon at the Northern Hospital, Liverpool. Mothersole settled in practice at Bolton, Lancashire in 1892, and remained there throughout his life. He was surgeon to the Infirmary, which was granted a Royal charter during his life-time, and as a young man he was responsible for introducing strict aseptic practice there. He was chairman of the Bolton division of the British Medical Association 1922-26 and 1928-34, and president of the Lancashire branch of the Association 1932-33; he represented his constituency at the annual representative meetings from 1920 to 1932. He contributed numerous case reports to the professional journals. Mothersole had an original mind and sound judgement; his energy supported by his tact and kindly sympathy made him a very popular and successful practitioner. After retiring from practice he took an active part in civic affairs and was elected an Alderman of Bolton. Mothersole married in 1894 Susanna Mary Ralfe, who survived him but without children. He died at 33 Fourth Avenue, Bolton on 12 May 1950, aged nearly 86. He had practised at 128 St George's Road, Bolton. Publications: An operation for parotid fistula. *Practitioner*, 1910, 84, 263. A short series of operations for intestinal stasis. *Brit J Surg* 1915, 2, 664.