"As for technical material, I have never used a great quantity. Of
course I do scales and vocalizes for a short time each day; such things
are always kept up. Then I make daily use of about a dozen exercises by
Rubini. Beyond these I make technical studies out of the pieces. But,
after one has made a certain amount of progress on the technical side,
one must work for one's self--I mean one must work on one's moral
nature.