Google Books indicates that this quote:

"Who likes gravy on dar taters, Repeat.
Say dem greasy words ober agin.
Ole Guinea nigger glutton,
Eat a whole leg ob mutton,
Eye shine like pewter button,...,"

can be found in Christy's and White's Ethiopian Melodies, by George N Christy and Charles White (Philadelphia: T.B. Peterson & Brothers, 1854), page 40. This book can be found in several university libraries. This is a book of some 200 songs.

Unfortunately, I can't find images online.