The Parts That Stay

Soren's grandmother had lived in this room for sixty years, and now there was a bare patch on the wall where her mirror used to hang.

"Every wall in here has been painted at least four times," she said from the doorway, holding a mug of coffee she wasn't drinking. "Different color each time. You'd never know there's yellow under the blue under the green."

Maya pressed her thumbnail into a flaking corner. Layers came up like the pages of a tiny book.

"So none of it is the same as when you moved in," Maya said.

"Not a speck." Grandmother smiled and went to find more tape, leaving them with the rollers.

Soren dipped his roller and didn't roll. "That's true about us too, you know. People. We get repainted."

"What do you mean, repainted."

"Your cells. They wear out and get replaced. Skin, every few weeks. The lining of your stomach, days. Your whole skeleton, it swaps itself out over years. The body you have now isn't made of the same stuff as the body you had when you were little."

Maya stopped. She held the roller in the air, dripping.

"Say that again."

"You're not made of the same atoms you were born with. They've been replaced. Most of you has been thrown out and rebuilt."

"That's wrong," Maya said.

"It's not wrong, it's actually -"

"No." She set the roller down in the tray. "Some of it's right. But something's wrong. Because I remember being four."

Soren waited. "I remember the kitchen in our old apartment," she said. "The exact green of the cabinets. I was four. If the part of me that remembers got thrown out and rebuilt, the memory would go in the trash with it. Like the yellow paint under the blue. You can't see the yellow anymore."

"You can sort of see it. If you scrape."

"You can't scrape a memory back. Either it's there or it isn't. And mine's there." She frowned at the wall. "So either you're wrong, or something in me didn't get repainted."

Soren put his roller down too. He pulled his notebook from his back pocket and opened to a clean page and wrote skin weeks. stomach days. bone years. memory ???

"Okay," he said slowly. "What would have to be true. For you to remember being four."

"The thing that holds the memory has to be old. As old as the memory. Older."

"As old as you."

"As old as me," Maya said. "It would have to be a part that never got replaced. Not once. The original."

They looked at each other across the half-blue wall.

"The brain," Soren said. "It would have to be the brain."

He was already writing. "But not all of it, that doesn't work either, because brains do change, they grow new connections, that's how you learn -"

"Connections can be new," Maya said. "The wires between the things. But the things themselves. The actual cells where the memory lives. Those have to be the same ones. The first ones."

Soren stared at the page. Then he laughed, a short surprised sound.

"I think you just figured out something real. The neurons in your cortex. The thinking part, the outer part. Most of those, you're born with them and you die with them. They don't get replaced. The ones you have right now were there when you were four. When you were a baby. They're the oldest part of you."

Maya sat down on the dropcloth.

"Say more."

"It's not just the brain. I read this. There are a few parts that never swap out. The lens of your eye -" he touched the skin under his own eye, "the clear part you see through. The cells in the center of it are the original cells. From before you were born. You've been looking at the whole world through the exact same lens your entire life."

"The same one I saw the green cabinets with."

"The same one. And your heart. The muscle cells that squeeze, the cardiomyocytes. Almost all of them are the ones you started with. Your heart has been beating with the same cells since before you had a name."

Maya put her hand flat on her own chest, not for drama, just to feel it. The wall behind her was four colors deep and none of them original. The dropcloth under her was somebody else's old sheet. Even the dust in the light was new dust.

"So almost everything about me gets thrown out and rebuilt," she said. "My skin isn't the skin that touched anything I remember. My hands aren't the hands. But there are three places that are still original. My eyes. My heart. And the part of my brain that's holding the green cabinets."

"Three places that have been with you the whole time," Soren said. "And will be. Right to the end. They're the only parts of you that meet your whole life."

Maya was quiet. Then she said the thing he hadn't gotten to yet, the thing that made his arms go cold.

"Then those three are the only parts that were here for everything. Every single thing that ever happened to me. There's a piece of me right now, behind my eyes, that watched my whole life happen and was never once replaced." She looked up. "The four-year-old isn't gone. She's not under the paint. She's still here. She's the same cells."

From the hall came Grandmother's voice, asking if they wanted the trim white or cream.

Neither of them answered. Maya was looking at the bare patch where the mirror had been, the one square of wall that had never needed repainting because nothing ever hung there to wear it down.

Soren turned to a new page and didn't write anything yet. He held the pen above the paper and watched his grandmother's hand come around the door frame, sixty years old, holding two cans of paint, steadied by a heart that had never once stopped to be replaced.