How does Mrs. Dean describe Catherine's behavior when she first encounters her in her room in Chapter 12?

Catherine begins tearing at her pillows with her teeth, and cannot recognize her own face in the mirror. She is delusional, and has trouble remembering the time or place. She makes Nelly open a window, anxious to feel the air from the moors. She yells out to Heathcliff that even if she dies, she will not rest until they are together.