He was born in Edinburgh on 6 March 1839 the son of Elizabeth Allan Thomson and her husband, Andrew Douglas Maclagan, a surgeon.
[3] Alongside his medical career he was a military volunteer and held the rank of Colonel with the 5th Battalion Royal Scots.
[4] He died on 12 July 1919 at home at 5 Coates Crescent in Edinburgh's West End, where he had lived for at least 40 years.
[6] He worked in a team of dedicated collectors, in the West Highlands and they collected a huge amount of material, that covers topics as diverse as folk medicine, customs and beliefs, hero tales, material culture, rhymes and children's games, recipes and weather lore, place-name legends, the natural world and much more.
The manuscript itself totals more than 9000 pages and is held in the University of Edinburgh School of Scottish Studies Archive.