I perform both versions of the above; "Scratch him.." and "Massas gone away..." They do have different melodies and as far as I am concerned are different songs. This situation is not uncommon for the period; it seems to be a type of Title plagerism. And also many authorships of that time are in question. It was not unheard of for a performer to "lay claim" to a song that he had heard somewhere. Another good example of this type of occurance is "Mary Blane." The title was maybe more famous than the song and there are two widely published very different versions with many different (claimed) authorships.