[1] He was born in Edinburgh, the son of Dr James Duncan and his wife Margaret Balfour (1819-1895), then residing at 7 Dundas Street.

[4] He then spent two years in continental Europe studying surgery in Berlin, Vienna and Paris.

[7] He began to teach surgery at the Extramural School in 1871, where he developed a reputation as an excellent teacher, attracting large numbers of students to his classes.

[9] He was an unsuccessful applicant in 1888 for the chair of surgery at the University of Edinburgh, along with Joseph Bell and Patrick Heron Watson.

[11]He died at Kinloch Lodge on the Isle of Skye on 24 August 1899, a few days after his 60th birthday and is buried in the Dean Cemetery, Edinburgh.

His father James Duncan (1810-1886) inherited the company, becoming a director in addition to pursuing a career as a surgeon in Edinburgh.

One of his nephews was William James Stuart (1874-1959), who was President of the Royal College of Surgeons of Edinburgh from 1937 to 1939 On the Surgical Applications of Electricity: Introduction to a Course of Lectures on Systematic Surgery.