The story would lose its charm and reality without the mirror because it fascinates both the characters i.e., doctor and the snake. The doctor makes two important decisions - saving daily and growing thin moustaches to make himself more handsome and keeping a smile on the face all the time while looking at himself in the mirror. The snake also feels attracted to look at his face in the mirror and leaves the doctor’s arm. It sits on the table in front of mirror and the doctor finds an opportunity to move away to save himself. Thus, the story does revolve around the mirror and therefore its important.