Major Douglas James Stirling Armstrong was the son of Dr William Hunter Stirling and Beatrice Joan Armstrong, of Glasgow.
22 May 1840 Temporary Assistant Surgeon Ordnance Medical Department.
15 Apr 1841 Promoted Assistant Surgeon Ordnance Medical Department, vice Assistant Surgeon William Richardson.
Malta Mar 1847 Arrived at Malta.
1 Apr 1854 Surgeon Ordnance Medical Department.
22 May 1860 Surgeon Major Royal Artillery.
11 June 1861 Surgeon Major 21st (Royal North British) Fusiliers Regiment of Foot.
7 Mar 1865 Appointed Staff Surgeon. The subsequent vacancy in 21st Foot was filled by Surgeon William Stewart 18th Foot, while Staff Surgeon James Henry Lewis became surgeon 18th Foot vice Stewart.
Malta 9 June 1869 Arrived from England on appointment.
Malta 1 Jan 1870 On duty at Forrest Hospital St Julians. Detachments of infantry occupied the barracks and huts at Pembroke Camp for the annual instruction in musketry from 1 Jan to 3 Mar, and from 5 Oct to 31 Dec 1870. The sick from the Camp were admitted to Forrest Hospital (Spinola Palace) St Julians. Between 1 January and 3 March 1870, Forrest Hospital was under medical charge of Staff Surgeon-Major Mackintosh.On 3 March, the hospital was transferred to 87th Regiment for the summer season. It was re transferred and opened as a detachment hospital on 5 October
Malta 3 Mar 1870 On duty at The Valletta Hospital.
Malta 1871 On duty at The Valletta Hospital. Resident at 65 Strada Brittanica Valletta.
Malta 12 May 1872 On duty at the Forrest Hospital prior to leaving Malta.
11 Sept 1872 Retired to half-pay.
5 Sept 1890 Died at Malta of heart disease. Was buried on 7 September at Ta' Braxia Cemetery Pieta.
- Entry No: 4631. Johnston W. Roll of Commissioned Offices in the Medical Service of the British Army. Vol 1 (20 June 1727-23 June 1898), Aberdeen (1917).
- TNA:CO 158/223, Returns of the General and Staff officers of the hospitals attached to the Forces in Malta (April–July 1870).
- Succession Book Vol 2 (1 May 1846). Returns of service of medical officers in the Regular Army.
- TNA:CO 158/218 Malta Original Correspondence, Returns of Staff Officers Malta Garrison (January–May 1869).