The N-Word only occurred once in the original Mikado - in the Mikado's song. In defense of W.S. Gilbert, I don't think the word in the England of the time was a pejorative, it was more of a color (colour). However, I approve of the change, doubtful though its meaning may be. I wonder if there is a record of when it changed and who changed it. I doubt me it was WSG.