"That a conductor or performer may lose sight of the expression of a piece and be unconscious that he is so doing, is a commonplace. This may arise not so much from lack of artistic perception as from his giving undue attention to some particular aspect or aspects of the work in hand – correctness of music, rigid regard to tempo, literal performance of the p's and f's of the copy – so that it or they crowd out the poetic element of expression, and instead of his being an emotional artist he is merely a human metronome."