The Music Cure by George Bernard Shaw — Read

Preface:

This is not a serious play: it is what is called a Variety Turn for two musicians. It is written for two pianists, but can be adapted to any instruments on which the performers happen to be proficient. At its first performance by Miss Madge McIntosh and Mr. William Armstrong the difficulty arose that, though Mr. Armstrong was an accomplished pianist, Miss McIntosh's virtuosity was confined to the English concertina. That did just as well.