he was born the son of rev john stuart dd (1816-1886) minister of st andrews parish in edinburgh, and his wife, jessie duncan, daughter of dr john duncan (an eminent surgeon and founder of the medical chemical company duncan & flockhart). the family lived at 7 northumberland street, a large terraced georgian townhouse in edinburgh's second new town. he was educated at edinburgh academy close to his family home, then studied medicine at edinburgh university graduating mb chb in 1899.