MRCS LSA 1861; MB Lond 1868, MD 1876; FRCP 1882; DSc Manch 1895.
Leech was born in Urmston on 12 January 1840, the son of a Manchester general practitioner. He came from a Cheshire family, which included the fifteenth century doctor of physic, John Leech, of Lumb, Audenshaw. Leech entered Owens College Manchester in 1854 and in 1856 became a pupil of Mr Richmond, then in practice in Manchester. In 1857 Leech entered the Royal Manchester School of Medicine where he received his medical education and later became demonstrator in anatomy. After graduating, Leech worked for a time in London and Paris before returning to Manchester where he joined Mr Richmond in practice, and later succeeded him. Leech later became a leading Manchester physician. In 1870 Leech was appointed physician to Hulme Dispensary, an institution in its infancy. In 1873 Leech became assistant physician to MRI; in 1878 was appointed physician and later became senior physician. He resigned in 1899 and was appointed consulting physician. Leech took an active role in the establishment of the Manchester and Salford Hospital for Skin Diseases, at which he was consulting physician. He was also involved in the establishment of the Cancer Pavilion and Home [later Christie Hospital], to which he was honorary physician. Leech was also honorary physician to the Deaf and Dumb Institution at Old Trafford.
Leech was appointed lecturer in materia medica and therapeutics at Owens College in 1876 and formed a well respected museum for materia medica. He became the first professor of materia medica and therapeutics at Owens College in 1881, holding this position until his death. Leech was also chairman of convocation and later pro-vice-chancellor of the Victoria University and representative of the Victoria University on the British Medical Council. Leech took a particular interest in sanitary reform, joining the Manchester and Salford Sanitary Association in 1869. The following year he became honorary secretary and produced a number of important reports for the annual meetings, before resigning the position in 1873, later being elected vice-president. Leech was president of MMS from 1883-1884 (the year of its fiftieth jubilee) and in 1887 was vice-president of the therapeutic section of the British Medical Association. In 1877 he was honorary secretary of the Lancashire and Cheshire Branch of BMA and in 1890 was president. Leech founded the Manchester Therapeutical Society in 1897 and was its first president. Leech was particularly interested in pharmacological and therapeutic research, and delivered the Croonian Lectures on these subjects to the Royal College of Physicians in 1893. He was also a strong supporter of the Medical chronicle, of which he was editor for five years. Leech was the uncle of EBL. He died on 2 July 1900 aged 60 and was buried in Southern Cemetery (there is also a plaque in his memory at All Saints Church, Darton). In his will, Leech left £10000 to the University of Manchester to endow a professorship of materia medica and therapeutics. A fund was raised to support this and a portrait was painted by George Harcourt.