Surgeon–Major Thomas Knox Birnie entered the army as an assistant surgeon in November 1852. He served with the 1st Royals in the Crimea from 7 May 1855 and was at the siege and fall of Sebastopol. He received the medal with clasp and the Turkish Medal.
In 1860, in which year he reached the rank of surgeon, he served throughout the campaign in North China. He was present at the storming and capture of Sinnoh and Tangku and the surrender of Pekin. For this campaign, he received the medal with two clasps.
While in China, Assistant Surgeon Thomas Knox Birnie's friend Colonel Urquhart received a letter from the Royal Botanic Gardens Kew
in which was a request for him to send some of the plants of the northern provinces. While they were encamped in Talien Hwan Bay in Chinese Tartary, Knox Birnie made a small collection of the wild flowers there, totalling about 50 or 60. On his return to London, he left his collection in the care of his uncle, who presented it to Kew. Knox Birnie had also made a collection of about 250 or 300 plants while in the Crimea, which he also presented to the Royal Botanic Gardens.1
Service Record — Thomas Knox Birnie
23 Nov 1852 Acting Assistant Surgeon.
7 Jan 1853 Staff Assistant Surgeon vice Staff Assistant Surgeon
Ethelbert Henry Blake promoted surgeon 55th (Westmoreland) Regiment of Foot.
14 Jan 1853 Assistant Surgeon 2nd/1st, The Royal Regiment of Foot.
7 May 1855 Served in the Crimea with the 2nd Bn/1st, The Royal Regiment.
He was present at the siege and capture of Sebastopol.
Malta 11 June 1856 Arrived from Turkey. At St George's Bay.
Malta 21 May 1857 Left for Gibraltar.
25 Sept 1860 Promoted Staff Surgeon.
In 1860, served in North China, where he was present at the storming and capture of Sinnoh and Tangku, and the surrender of Pekin. On his return to London, he was at once ordered to Buttevant County Cork, Ireland, on promotion, to take over the medical charge of the fifteenth Depot Battalion.
1861 – 1862 At Gravesend, Kent.
29 July 1862 Surgeon 2nd/12th (East Suffolk) Regiment of Foot.
12 Dec 1868 Promoted Staff Surgeon.
1869 On duty at Parkhurst.
8 Dec 1869 Surgeon 2nd/17th (Leicestershire) Regiment of Foot.
19 July 1870 From 17th Foot exchanged with Staff Surgeon Joseph Coleman Hornsby Wright.
1871 – 1874 Served in Bombay.
23 Nov 1872 Promoted Surgeon–Major.
June 1874 Medical Officer 66th Foot.
1878 Moved to the Staff Bombay from 66th Foot. Returned from Bombay to Wrexham.
1 Feb 1879 Retired to the half-pay of surgeon 1st Foot.
1 Feb 1880 Granted the honorary rank of Deputy Surgeon General.
31 Dec 1889 Died at St Leonards on Sea aged 64 years.