Kitty watches the mazurka

The quadrille passes pleasantly; Kitty waits for the mazurka, which she believes will settle everything, and refuses five partners for it. Then, vis-à-vis to Anna in the last quadrille, she recognises the symptoms of elation she knows in herself and asks who has caused it — all, or only one. Watching Vronsky she is filled with horror: his firm calm is gone, and every time he turns to Anna he bows his head as though he wished to fall down before her, with an expression like an intelligent dog that feels guilty. When the mazurka is called Kitty has no partner and sinks into a chair in a little drawing-room, broken-hearted, until Countess Nordston has Korsunsky ask her. She dances in the first pair opposite the two of them, seeing that they feel alone in the crowded room. Anna's charm now seems to her terrible and cruel — 'something strange, satanic, and enchanting'. Anna refuses supper and goes.

The affair's decisive scene is given entirely to the witness, so the reader learns what Anna and Vronsky are to each other before either of them admits it. Kitty's expertise is what makes her testimony reliable: she identifies Anna's intoxication because she has felt it. 'Satanic' is her word, not Tolstoy's, and the novel spends seven parts adjudicating it.