On 1 March 1882, Theodor Kullak died. He is probably best known simply for the comment Franz Liszt made when the amount Kullak had earned from teaching was revealed: ‘You do not rake in a million marks without performing some sacrifice at the altar of Art’. Liszt, true to his indictments, did not ask for a penny for his lessons.
Now that we're done applauding him, it becomes apparent that, except in the coming of a socialist revolution, to act like that will remain quite impossible to sustain, financially. So, instead of a direct example, it acts as a hallmark of purity – a guarantee that the values that Liszt furthered through his lessons were, and indeed are, solely for the sake of music.
Unlike Kullak, he really had no singular structure to his lessons, most of his choices being instinctual. Amy Fay, an American pianist and music chronicler (also a former student of Kullak) wrote: ‘You feel so free with him, and he develops the very spirit of music in you. He doesn't keep nagging at you all the time but leaves you to your own conception. Now and then he will make a criticism, and with a few words give you enough to think about for all the rest of your life. He doesn't tell you anything about technique. That you must work out for yourself.’ Those ‘few words’ were often aphorisms, useful both in their ability to summarise difficult concepts, and the occasional smirks it might garner from the pupils.
Although, as Fay said, he wasn't known for ‘nagging’, he would sometimes ask a student to repeat a bar 10 times until the expression was just right and the shading sufficiently subtle. All this reminds me of the conductor Furtwängler, who like Liszt sought a music that expressed meanings and emotions transcendent of the capabilities of words. This, if anything, was the reason for his glut in technical espousing – his lessons were about expression, and how to achieve it in your own way: the very foundation of great playing. A quote so famous that it nestles among his Wikipedia page is an sufficient justification as any – he expected them to ‘wash their dirty linen at home’.
Certainly quite an approach, but in the end did it pay off? Well, if the names Hans von Bülow, Carl Reinecke, Alexander Siloti, and Emil von Sauer mean anything to you, it is proof that perhaps it did.