Born at Salisbury and was educated at University College and Hospital, London. He served as House Surgeon at the Liverpool Northern Hospital from 1875-1877, and in 1878 began to practise at Eastbourne as Assistant to Robert Colgate (qv), whose daughter, Mary, he married in 1881. He succeeded his father-in-law as Medical Officer to the Union Infirmary and was a member of the original staff of the Princess Alice Memorial Hospital, where he soon became known as a brilliant surgeon. During the War of 1914-1918 he was Senior Surgeon to the Red Cross Base Hospital at Eastbourne and was placed in charge of Urmston VAD Hospital. In 1919 he was appointed Medical Officer to the All Saints' Convalescent Hospital, and for his services was rewarded with the OBE. He died at Grasmere, Meads Road, Eastbourne, on September 16th, 1923, survived by two sons and three daughters, his wife having died in 1918. Farnell was an excellent administrator. When he went to the Northern Hospital at Liverpool as House Surgeon there had been much erysipelas and pyaemia; when he left two years later Listerian methods were in regular use and the wards were comparatively free from suppuration.