“I don’t remember that,” Derry said, but she looked pleased at the thought of the burning cap. “I don’t remember Belgrave Road at all.”

“The next time I have a clear memory of you,” I continued, “you must have been about three. We were living in Ranelagh. I went into the front bedroom and found you wandering around in your skin, crying for someone to dress you, and I dressed you.”

“I don’t remember that,” Derry said.

“Well, do you remember when you were six or seven and almost got St. Vitus’s dance? You kept shaking and dropping things all over the house.”

“Oh, I remember that, all right,” Derry said, smiling.

All the time we were talking, she was hemming a pink cotton dress for her older daughter. I looked at her hands, so steady and sure with the needle, and I thought of how we had all feared she would lose the use of them.

“You were never able to help with the washing up,” I said, “for fear you’d break all the cups and saucers. When you weren’t dropping things, you lay on the bed with your eyes wide open, not able to wake up. You looked awful. You gave Mother a terrible fright. She got the woman from next door in to look at you.”

“I remember all that,” Derry said impatiently.

“But you were asleep,” I said.

“I was no more asleep than you are now,” she said. “And I was no nearer getting St. Vitus’s dance than you are now, either,” she added, this time with a touch of defiance.

I stared, or glared, at her. “What do you mean?” I cried.

She looked me straight in the eye, but the color began to rise in her face.

“Do you mean to tell me you were putting it all on?” I cried, sounding almost as thunderstruck as I felt. Derry’s delicate health had loomed as importantly in my childhood as the Catholic Church and the fight for Irish freedom. The first word I ever remember hearing about Derry was that she had been underweight when she was born and that her health was precarious. My mother always dressed us exactly alike, and people used to call us Mrs. Brennan’s twins, but I was the large, hardy twin and she was the thin, pale one, always with me, and always silent, while I talked endlessly. Remembering how strongly all this had shaped our childhood, and the way it had determined everything between us and around us, I naturally was aghast to hear her now, more than twenty years later, calmly tearing it all away. I decided that she was joking.

“You’re joking, aren’t you?” I said.

“I am not,” she said.

“But why did you do it?” I asked.