Hi, Cheri - there's a message above that links to the 1865 version of the song at the Levy Sheet Music Site (click). As long as you stick to the 1865 version of the song, you have no need to seek copyright permission. In the U.S., almost everything published in 1923 and earlier is in the public domain - and I think U.S. law is the one that is most generous to copyright holders (and most restrictive on the rest of us).
With a song published in 1865, there's no question at all - it's in the public domain.
-Joe Offer-