Clawing wrong notes

At the Guardian, James Fenton offers fascinating thoughts on various aspects of musical performance (spurred by a book that sounds altogether most like what I am curious to see, Kenneth Hamilton's After the Golden Age: Romantic Pianism and Modern Performance--I must get this!):

Applause between movements appears to have died out some time around 1940-50, later than I would have expected. Hamilton implies that silent appreciation began with Dutch audiences, but spread through the influence of recorded music: one wouldn't applaud a record. But there is a creeping gentility involved as well, and a feeling of being overawed by your neighbour's disapproval, a fear of committing a faux pas.

At the same time as the applause shrivelled away, the pressure was on for pianists to become note-perfect. This they simply had not been. Hans von Bülow almost instructed his students to make mistakes: "In large leaps, now and then you must claw a wrong note; otherwise no one will notice that it is difficult." The audience liked this. Wrong notes, we are told, were considered a sign of genius. Eugen d'Albert was celebrated for the wild inaccuracy of his playing. Busoni told one player who had ventured to demur: "If you put as much conviction into your right notes as d'Albert does into his wrong ones, then you'd have cause to criticise."

The player as improviser was contemporaneous with the pianist who was required to play from memory. The great Alfred Cortot was very bad at this, and used to try whatever came to mind. Beecham recalled conducting with him: "We started with the Beethoven, and I kept up with Cortot through the Grieg, Schumann, Bach and Tchaikovsky, and then he hit on one I didn't know, so I stopped dead."

If your memory failed utterly, Theodor Leschetizky advised you to turn angrily to the audience and complain that a certain note was disgracefully out of tune, then leave the stage demanding a tuner. "The pianist," Hamilton tells us, "could then surreptitiously consult his score in the artist's room while the tuner dealt with the allegedly offending note."