Family Search: When Lieutenant Thomas Dougall was born on 11 November 1898, in Walthamstow, Essex, England, United Kingdom, his father, Robert Thomas Dougall, was 35 and his mother, Amy Dongall, was 25. He immigrated to Canada in 1913 and lived in Ealing, Middlesex, England, United Kingdom in 1911. He registered for military service in 1914. In 1914, at the age of 16, his occupation is listed as labourer. He died on 19 August 1917, in Barlin, Pas-de-Calais, France, at the age of 18, and was buried in Barlin Communal Cemetery Extension, Barlin, Pas-de-Calais, France.
Summary of Soldier at the Canadian War Museum
Medal Set for this soldier at the Canadian War Museum
Military Cross, Medaille Militaire
Under age.
Sat, Mar 03, 1917 ·Page 5
This man may have enlisted with the 18th Battalion CEF underage. His age on that date (October 24, 1915) is listed as 18-years, 11-months, yet on his death on August 19, 1917, his age is listed as 19-years old. This would mean he was approximately 17-years old when he enlisted.
His ability as a soldier was represented with his rise in rank from a private to acting-corporal in the field on June 16, 1916. He then was commissioned to the rank of lieutenant on February 17, 1917. It appears this man did not go to England to attend an officer’s course, which was the normal procedure for men promoted from the ranks.
He earned the Medaille Militaire from the French Republic on May 1, 1917, and then the Military Cross on September 26, 1917 (London Gazette. September 25, 1917. Supplement no. 30308. Page 9981. This award was promulgated after his death.
The 18th Battalion War Diary relates in an entry July 22, 1917: “During this tour LIEUT. T.R. DOUGALL rendered valuable service and obtained valuable information by making 3 daring reconnaissances among the buildings in NO MANS LAND. At M.19.a.70.00 and N.19.0.80.70 he searched these houses and German dugouts in the vicinity. 2 of these reconnaissances were made during daylight and from information gained he was able to direct artillery fire on T.M. [trench mortar] emplacements.”
The Military Cross citation reads:
For conspicuous gallantry and devotion to duty. He made two valuable daylight reconnaissances into houses in “No Man’s Land” and discovered machine gun emplacements, dug-outs and tunnels, as well as two trench mortar emplacements, upon which he was able to direct our artillery fire with great success on returning to our lines.
Source via Dawn Heuston via the 18th Battalion Facebook Group. London Gazette dated August 1, 1918.
Thomas Dougall was born in England in 1897 but was a labourer residing in Guelph when he enlisted as a private in October 1914. By 1917, Dougall had been promoted to sergeant. In February of that year, he earned the Military Cross and the French Medaille Militaire “for conspicuous gallantry and devotion to duty. He made two valuable daylight reconnaissances into houses in no man’s land and discovered machine gun emplacements, dugouts and tunnels, as well as two trench mortar emplacements, upon which he was able to direct our artillery fire with great success.”
In addition to being decorated, Dougall was promoted to lieutenant. A few months later, on Aug. 19, he died from shrapnel wounds. Dougall was 19 years old.
Note that this summary may actually refer to a series of actions carried out in mid-July 1917. The 18th Battalion War Diary records on July 22nd, 1917:
“During this tour LIEUT. T.R. DOUGALL rendered valuable service and obtained valuable information by making 3 daring reconnaissances among the buildings in NO MNS LAND. At M.19.a.70.00 and N.19.0.80.70 he searched these houses and German dugouts in the vicinity. 2 of these reconnaissances were made during daylight and from information gained he was able to direct artillery fire on T.M. [trench mortar] emplacements.”
History of the 18th Battalion CEF, "The Fighting Eighteenth" 
https://www.warmuseum.ca/collections/artifact/1126281/?q=18th+battalion&page_num=1&item_num=10&media_irn=5471035