This text comes from The Canadian Soldiers' Song Book, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
Sure a little bit of shrapnel fell from out the sky one day,
And it nestled in my shoulder in a kind and loving way,
And when the M.O. saw it,
Sure it looked so sweet and fair,
He said "You're off to Blighty,
They will fix you up back there."
So he sprinkled it with iodine, to keep the germs away,
It's the only way to stop them no matter what you say,
But before I left the CCS. he changed his fickle mind,
And he marked me down for duty and he sent me up the line.