wardmaster said:I think it might be from the (early) First World War song, Goodbye Dolly Gray. Google will give you the whole song, but the chorus is:
Goodbye Dolly, I must leave you,
Tho' it breaks my heart to go.
Something tells me I am needed at the front to fight the foe.
See the soldier boys are marching,
And I can no longer stay.
Hark! I hear the bugles calling,
'Goodbye Dolly Gray, Gray! Gray!
I say early First World War because the songs got less patriotic when thousands of troops had died at the Front.