James Foulis Duncan was the last of the Duncan family to own Farnham House, a private asylum in Finglas, County Dublin, Ireland. He served as president of the King and Queen's College of Physicians in Ireland (1873–1875) and of the Medico-Psychological Association (MPA) in 1875.

Duncan's mother died when he was young so he grew up with his father at the asylum. They ate with the patients and Duncan's earliest lessons in Latin, mathematics and science were provided by patients whom he later described as the best and noblest persons of our race, of gifted intellect and high attainment.

Building on this unusual but effective foundation, Duncan graduated from Trinity College Dublin in 1837. Throughout his medical and psychiatric career, Duncan was acutely socially aware, especially of the effects of poverty on health. He supported the use of scientific comparisons to test treatments (in language that prefigured later ideas about clinical trials) and was highly religious in outlook, as evidenced in his 1852 publication, God in Disease, or, The Manifestations of Design in Morbid Phenomena.

In his presidential address to the MPA in 1875, Duncan vehemently denounced a great many features of 19th-century life, ranging from the substitution of machinery for handicraft labour to the employment of children in factories and consequent loosening of family bonds. He was not, however, a man to be easily defeated, not even by great, unstoppable forces of history. Duncan saw education as the answer to all of these problems and advocated for better medical education, broader public education, and moral education of the young, which he felt held the greatest hope for preventing mental disorder.

Duncan typified a certain model of 19th-century asylum doctor: enterprising, powerful, prolific and keen to promote asylum medicine in the eyes of other doctors and the public. He died on 2 April 1895 at the age of 83 years. Obituaries in the British Medical Journal and Medical Press noted the professional esteem in which he was held, as well as his devotion to the promotion of religion and his reputation as a man of charity.

Image reproduced by kind permission of the Royal College of Physicians of Ireland.