The final moment of Long Day's Journey seems to highlight one of the major themes of the play – memory and the past. "Highlights" may not be a strong enough word. It seems to put the theme in bold, italics, and throws a couple exclamation points in to boot.
Here's what happens: Mary descends the stairs, lost in a morphine haze. Her hair is braided into girlish pigtails, her wedding dress draped across her arm. She recounts a tale of Mother Elizabeth, a nun at the convent school she attended. Mary ends by remembering when she met and fell in love with James Tyrone. It seems that Mary has gone beyond casual remembering and is almost drowning herself in the past. Why might she do such a thing? And what does it say about the play as a whole?
Let's take a second to pick apart some of these details or this last moment. First, there's the pigtails. That's a no-brainer. It's the hairstyle of a young girl, quite possibly the style in which she wore her own hair as a child. Could Mary be looking for the innocence she had as a girl, before the big bad world wrecked her life? There's a good chance of it.
Then there's Mother Elizabeth. Mary told the nun that she had a vision from the Virgin, calling Mary to become a nun herself. Mother Elizabeth advised Mary that she should wait a couple of years and then decide. Did you notice all the mother imagery in this little story? You've got Mother Elizabeth and the Virgin Mary, Mother of Jesus. Are these the figures that Mary has been digging so desperately in the past to find? Mary describes Mother Elizabeth as "sweet and good" and admits that she loves "her better than [her] own mother" (4.1.242). Then, of course, there's the Virgin Mary, who in the Christian tradition often seen as the most perfect unspoiled mother of all time. Does our Mary wish she could live up to her namesake? We figure that it's probably not a coincidence that the guilty, drug-addled Mary wants to lose herself in memories of untainted mother figures. Could she see in them the mother she failed to be? Does she blame them for deserting her?
Last but not least, we have two reminders of Mary's marriage to James Tyrone. There's the wedding dress, a pretty obvious symbol of the wedding to which she wore it. We should also take note that wedding dresses in general symbolize innocence and virginity. Is Mary looking for some lost purity?
Then, of course, there's the famous heartbreaking last line – "Then in the spring something happened to me. Yes, I remember. I fell in love with James Tyrone and was so happy for time" (4.1.242). Is Mary comforted by this brief flash of happiness? Or is she tortured by it, because of all the badness that followed after? Chances are, as is the case so often in the play, this memory is a comfort and a torment at the same time.
But what might Mary's final descent into memory say about the overall play? We have a theory. As you read the play, take note of the pattern of Mary's remembrances. Slowly but surely, with the aid of morphine, she moves backwards in time. She starts mostly harping on the recent past – the miserable hotels, James being cheap. Then she moves backwards to Edmund's painful birth and Eugene's painful death. Back and back she goes until finally at the end we have her convent days and the beginning of her relationship with Tyrone.
O'Neill ends the play at the beginning. In a way, the play cycles backwards and forwards at the same time. All the Tyrones generally follow this same regressive or backward trajectory. (Check out each Tyrone's "Character Analysis".) While the Tyrones do progress forward through the day, they are gradually dragged into the past by the weight of their memories. Mary's final descent seems to be a brilliant punctuation mark to this fascinating structure. Mrs. Tyrone probably sums up this pattern best when she says, "The past is the present isn't it? It's the future too" (2.2.103).