The following information was copied from the Royal Regiment of Canadian Artillary
Unfortunately the link is no longer on their website.

 
John McCrae, as both a surgeon and a gunner, had a long association with The Royal Regiment of Canadian Artillery. At the age of 15, John McCrae joined the Wellington Field Battery in Guelph as the unit's bugler. The unit (now 11th Field Artillery Regiment) was commanded by his father David. At 18, John was a gunner in the Battery. He remained with the Battery during his university studies, rising to the rank of Lieutenant in 1896.

Later, while studying pathology at McGill, McCrae was unsettled by the British defeats in the South African War which had broken out in October 1899. He obtained permission to postpone his fellowship, and was accepted for service in December 1899 in the second contingent of Canadian soldiers being sent to South Africa. He was made a Lieutenant in 'D' Battery, Royal Canadian Field Artillery which had been recruited from artillery units in Guelph, Ottawa, London and Port Hope. In one skirmish, his right section silenced the Boer guns near Rustenburg. During his service with 'D' Battery, he established a close friendship with Lieutenant (later Major General Sir) E.W.B. Morrison, from Ottawa, who commanded the left section which saw action at the famous battle of Leliefontein in support of the Royal Canadian Dragoons.

At the outbreak of the First World War in 1914, McCrae held the rank of Major in the Militia, and was a staff doctor at the Montreal General Hospital. Shortly after the war broke out he offered his services either as a doctor or a gunner. The 1st Brigade of Canadian Field Artillery (C.F.A.) was commanded by his old friend from 'D' Battery, now Lieutenant-Colonel E.W.B. Morrison, who wished McCrae to join him. Major McCrae was accepted as the Medical Officer of 1st Field Brigade C.F.A.

In the Spring of 1915, during the heaviest fighting of the second battle of the Ypres Salient in Belgian Flanders, McCrae and his dressing station were within sight of the Canadian cemetery. As the fighting continued, McCrae had his hands full caring for the wounded, and he watched with dismay as the little wooden crosses daily grew more numerous. Wild poppies were already beginning to bloom around the graves. After seventeen exhausting days, he sat down and wrote his immortal poem "In Flanders Fields", which was published by Punch magazine that December.

During the Second Battle of Ypres, the First Canadian Division suffered great casualties at the hands of the Germans, including the first use of Chlorine Gas, but managed to hold back the German Advance. Four Canadians won the Victoria Cross. The Second Battle of Ypres brought the war home to Canada, and served as a stepping stone to the future Canadian success at Vimy Ridge.

Through John McCrae's famous poem, we wear poppies each November in remembrance of the great sacrifice Canadians have made in the defence of freedom.

McCrae's "In Flanders Fields" remains to this day one of the most memorable war poems ever written. It is a lasting legacy of the terrible battle in the Ypres salient in the spring of 1915. Here is the story of the making of that poem:

Although he had been a doctor for years and had served in the South African War, it was impossible to get used to the suffering, the screams, and the blood here, and Major John McCrae had seen and heard enough in his dressing station to last him a lifetime.

As a surgeon attached to the 1st Field Artillery Brigade, Major McCrae, who had joined the McGill faculty in 1900 after graduating from the University of Toronto, had spent seventeen days treating injured men -- Canadians, British, Indians, French, and Germans -- in the Ypres salient.

It had been an ordeal that he had hardly thought possible. McCrae later wrote of it:

"I wish I could embody on paper some of the varied sensations of that seventeen days... Seventeen days of Hades! At the end of the first day if anyone had told us we had to spend seventeen days there, we would have folded our hands and said it could not have been done."

One death particularly affected McCrae. A young friend and former student, Lieut. Alexis Helmer of Ottawa, had been killed by a shell burst on 2 May 1915. Lieutenant Helmer was buried later that day in the little cemetery outside McCrae's dressing station, and McCrae had performed the funeral ceremony in the absence of the chaplain.

The next day, sitting on the back of an ambulance parked near the dressing station beside the Canal de l'Yser, just a few hundred yards north of Ypres, McCrae vented his anguish by composing a poem. The major was no stranger to writing, having authored several medical texts besides dabbling in poetry.

In the nearby cemetery, McCrae could see the wild poppies that sprang up in the ditches in that part of Europe, and he spent twenty minutes of precious rest time scribbling fifteen lines of verse in a notebook.

A young soldier watched him write it. Cyril Allinson, a twenty-two year old sergeant-major, was delivering mail that day when he spotted McCrae. The major looked up as Allinson approached, then went on writing while the sergeant-major stood there quietly. "His face was very tired but calm as we wrote," Allinson recalled. "He looked around from time to time, his eyes straying to Helmer's grave."

When McCrae finished five minutes later, he took his mail from Allinson and, without saying a word, handed his pad to the young NCO. Allinson was moved by what he read:

"The poem was exactly an exact description of the scene in front of us both. He used the word blow in that line because the poppies actually were being blown that morning by a gentle east wind. It never occurred to me at that time that it would ever be published. It seemed to me just an exact description of the scene."

In fact, it was very nearly not published. Dissatisfied with it, McCrae tossed the poem away, but a fellow officer retrieved it and sent it to newspapers in England. The Spectator, in London, rejected it, but Punch published it on 8 December 1915.