Emperor to page: "...which you will deliver to the Empress (Marie Louise) with your own hands. And above all, don't spare the horses. Go as fast as you can, and fear nothing."
From "The Happy Days of the Empress Marie Louise, ...1834-1900," by Imbert de Saint Amand (a 1912 translation). ebook.
------------------------------

Oxford Dictionary of Modern Quotations:
Song title 1934- Fred Hillebrand, Home James, and don't spare the horses. 8.62

Looks like Hillebrand wins in the home stretch!