When he was a boy, Aunt Georgina taught Clark the subjects of Latin, Literature (namely Shakespeare and mythology), and Music (specifically how to play the organ that her husband had bought for her).
The subject which Aunt Georgina seemed to care about the most was Music, which she encouraged Clark not to love too much, in case it was ever taken away from him. Clark tries to repay his Aunt Georgina for all of the lessons she taught him as a boy, by taking her to a concert.
Aunt Georgina also used to show Clark, when he was but a "gangling farmer-boy," how to milk cows on the farm, and she would talk to him about the opera, which she herself had loved in her youth.
Clark acknowledges that "most of the good that ever came (his) way" came his way because of Aunt Georgina and these subjects that she taught him as a boy.