“When the plan was made known to Mary, however, there was an end of all peace in it. She was so wretched, and so vehement, complained so much of injustice in being expected to go away, instead of Anne: Anne, who was nothing to Louisa, while she was her sister, and had the best right to stay in Henrietta's stead! And to go home without Charles, too, without her husband! No, it was too unkind! And, in short, she said more than her husband could long withstand; and as none of the others could oppose when he gave way, there was no help for it: the change of Mary for Anne was inevitable.” (Chapter 12)

Chapter 12 is definitely Mary’s worst day. I do not think that I have actually understood just how bad till this reading and everyone’s comments about it. Mary has acted in an extremely selfish manner by insisting she remain at Lyme when Anne was wanted by everyone else. As I see it, Mary’s speech in Chapter 7 in which she declares she is not “of any more use in the sickroom than Charles” is vastly more truthful than when she asks in Chapter 12 “Why was not she to be as useful as Anne?” That she would ask this question is amazing considering her recent declaration of “not” being useful in the sickroom and I must point to Chapter 2 again, “How quick come the reasons for approving what we like!” Try as I might I just cannot attribute Mary’s need to stay in any way that is a credit to her, neither excessive feeling for Louisa or hope of being useful can be seen in either her speech or actions. I have come up with four reasons why she wishes to stay:

“First, she cannot bear Anne to be singled out instead of her even if it is for sickroom duty, she has more right to stay and sees no reason to lend any of it to Anne, just as she explains in Chapter 6, “she did not see any reason why she was to be considered so much at home as to lose her place.” In Chapter 13 Mary’s hackles rise again when Charles suggests that Captain Benwick favors Anne and even though she is so displeased with his conduct towards herself she must correct Lady Russell’s idea of his relationship to them by saying “Oh! as to being Anne's acquaintance," said Mary, "I think he is rather my acquaintance, for I have been seeing him every day this last fortnight.” In Chapter 10, on the way home during the long walk Mary is once again as annoying as the opportunity allows, “She (Anne) joined Charles and Mary, and was tired enough to be very glad of Charles's other arm; but Charles, though in very good humour with her, was out of temper with his wife…which consequence was his dropping her arm almost every moment to cut off the heads of some nettles...when Mary began to complain of it, and lament her being ill-used…while Anne was never incommoded…he dropped the arms of both.”

Second, she cannot bear to be parted from Charles. When Anne first comes to Uppercross in Chapter 5, Mary says “I am so ill I can hardly speak” and the root of it seems to be that Charles is out enjoying sport while she is alone. “Oh! Charles is out shooting. I have not seen him since seven o'clock. He would go, though I told him how ill I was. He said he should not stay out long; but he has never come back, and now it is almost one. I assure you, I have not seen a soul this whole long morning.” In Chapter 7 Mary is reduced to peevish resentment at the idea that Charles would be dining at the other house without her. "So you and I are to be left to shift by ourselves, with this poor sick child; and not a creature coming near us all the evening! I knew how it would be…So here he is to go away and enjoy himself, and because I am the poor mother, I am not to be allowed to stir.” When asked to go home after Louisa’s fall in Chapter 12 she exclaims “And to go home without Charles, too, without her husband! No, it was too unkind!” I must say it is entirely possible that his going to Uppercross to deliver news of Louisa to his parents instead of attending Mary could have brought on her hysterics the morning after Louisa’s fall.