Hi, Andrea - did you get the lyrics right from the movie? This Google Search comes up with two pages of results - but so far, no credible information about the original source, or the tune. This page credits the quote to U.S. Chief Justice Harlan Fiske Stone (1872-1946), but I don't know about its credibility. This page, which seems more credible, calls it a barroom ditty titled Liquor and Longevity. There's another interesting reference on this page (click)
I did find it in print, titled "Liquor and Longevity," in an actual book: American Ballads (Compiled by Charles O'Brien Kennedy, 1952 - no tune) - exact words as above.
Google tells me it can also be found in a book called Everyman Book of Light Verse.

I'll betcha it was a recitation that was set to music for the movie.
I'm still looking....

-Joe-