All at once his position had shifted and he knew that something awful had happened.

He could not yet make out what had happened, when the white legs of a chestnut horse flashed by close to him, and Mahotin passed at a swift gallop.

Vronsky was touching the ground with one foot, and his mare was sinking on that foot.

He just had time to free his leg when she fell on one side, gasping painfully, and, making vain efforts to rise with her delicate, soaking neck, she fluttered on the ground at his feet like a shot bird.

The clumsy movement made by Vronsky had broken her back.