The final line of the 1734 song is

"This is to all Men the best of Physick."

(Never multitask!)

It's interesting that the earliest texts have "until it does run over," while later ones prefer "doth," which may have been substituted to make the song sound more ancient.

What surprises me is that while the "Three Jolly Coachmen" words were mentioned in 1943, no earlier printed reference has surfaced.