Christoph reached into the freezer, took out a vial, and pointed to the letters H-e-L-a written on its side. "There are millions and millions of her cells in there," he said. "Maybe billions. You can keep them here forever. Fifty years, a hundred years, even more-then you just thaw them out and they grow."

He rocked the vial of HeLa cells back and forth in his hand as he started talking about how careful you have to be when you handle them. "We have an extra room just for the cells," he said. "That's important. Because if you contaminate them with anything, you can't really use them anymore. And you don't want HeLa cells to contaminate other cultures in a lab."

"That's what happened over in Russia, right?" Deborah said.

He did a double take and grinned. "Yes," he said. "Exactly. It's great you know about that." He explained how the HeLa contamination problem happened, then said, "Her cells caused millions of dollars in damage. Seems like a bit of poetic justice, doesn't it?"

"My mother was just getting back at scientists for keepin all them secrets from the family," Deborah said. "You don't mess with Henrietta-she'll sic HeLa on your a.s.s!"

Everyone laughed.

Christoph reached into the freezer behind him, grabbed another vial of HeLa cells, and held it out to Deborah, his eyes soft. She stood stunned for a moment, staring into his outstretched hand, then grabbed the vial and began rubbing it fast between her palms, like she was warming herself in winter.

"She's cold," Deborah said, cupping her hands and blowing onto the vial. Christoph motioned for us to follow him to the incubator where he warmed the cells, but Deborah didn't move. As Zakariyya and Christoph walked away, she raised the vial and touched it to her lips.

"You're famous," she whispered. "Just n.o.body knows it."

Christoph led us into a small laboratory crammed full of microscopes, pipettes, and containers with words like BIOHAZARD and DNA written on their sides. Pointing to the ventilation hoods covering his tables, he said, "We don't want cancer all over the place, so this sucks all the air to a filtration system that catches and kills any cells that are floating around."

He explained what culture medium was, and how he moved cells from freezer to incubator to grow. "Eventually they fill those huge bottles in the back," he said, pointing to rows of gallon-sized jugs. "Then we do our experiments on them, like we find a new drug for cancer, pour it onto the cells, and see what happens." Zakariyya and Deborah nodded as he told them how drugs go through testing in cells, then animals, and finally humans.

Christoph knelt in front of an incubator, reached inside, and pulled out a dish with HeLa growing in it. "They're really, really small, the cells," he said. "That's why we go to the microscope now so I can show them to you." He flipped power switches, slid the dish onto the microscope's platform, and pointed to a small monitor attached to the microscope. It lit up a fluorescent green, and Deborah gasped.

"It's a pretty color!"

Christoph bent over the microscope to bring the cells into focus, and an image appeared on the screen that looked more like hazy green pond water than cells.

"At this magnification you can't see much," Christoph said. "The screen is just boring because the cells are so small, even with a microscope you can't see them sometimes." He clicked a k.n.o.b and zoomed in to higher and higher magnifications until the hazy sea of green turned into a screen filled with hundreds of individual cells, their centers dark and bulging.

"Oooo," Deborah whispered. "There they are." She reached out and touched the screen, rubbing her finger from one cell to the next.

Christoph traced the outline of a cell with his finger. "All this is one cell," he said. "It kinda looks like a triangle with a circle in the middle, you see that?"

He grabbed a piece of sc.r.a.p paper and spent nearly a half-hour drawing diagrams and explaining the basic biology of cells as Deborah asked questions. Zakariyya turned up his hearing aid and leaned close to Christoph and the paper.

"Everybody always talking about cells and DNA," Deborah said at one point, "but I don't understand what's DNA and what's her cells."

"Ah!" Christoph said, excited, "DNA is what's inside the cell! Inside each nucleus, if we could zoom in closer, you'd see a piece of DNA that looked like this." He drew a long, squiggly line. "There's forty-six of those pieces of DNA in every human nucleus. We call those chromosomes-those are the things that were colored bright in that big picture I gave you."

"Oh! My brother got that picture hanging on his wall at home next to our mother and sister," Deborah said, then looked at Zakariyya. "Did you know this is the man who gave you that picture?"

Zakariyya looked to the ground and nodded, the corners of his mouth turning up into a barely perceptible smile.

"Within the DNA in that picture is all the genetic information that made Henrietta Henrietta," Christoph told them. "Was your mother tall or short?"

"Short."

"And she had dark hair, right?"

We all nodded.

"Well, all that information came from her DNA," he said. "So did her cancer-it came from a DNA mistake."

Deborah's face fell. She'd heard many times that she'd inherited some of the DNA inside those cells from her mother. She didn't want to hear that her mother's cancer was in that DNA too.

"Those mistakes can happen when you get exposed to chemicals or radiation," Christoph said. "But in your mother's case, the mistake was caused by HPV, the genital warts virus. The good news for you is that children don't inherit those kinds of changes in DNA from their parents-they just come from being exposed to the virus."

"So we don't have the thing that made her cells grow forever?" Deborah asked. Christoph shook his head. "Now you tell me after all these years!" Deborah yelled. "Thank G.o.d, cause I was wonderin!"

She pointed at a cell on the screen that looked longer than the others. "This one is cancer, right? And the rest are her normal ones?"

"Actually, HeLa is all just cancer," Christoph said.

"Wait a minute," she said, "you mean none of our mother regular cells still livin? Just her cancer cells?"

"That's right."

"Oh! See, and all this time I thought my mother regular cells still livin!"

Christoph leaned over the microscope again and began moving the cells quickly around the screen until he shrieked, "Look, there! See that cell?" He pointed to the center of the monitor. "See how it has a big nucleus that looks like it's almost pinched in half in the middle? That cell is dividing into two cells right before our eyes! And both of those cells will have your mother's DNA in them."

"Lord have mercy," Deborah whispered, covering her mouth with her hand.

Christoph kept talking about cell division, but Deborah wasn't listening. She stood mesmerized, watching one of her mother's cells divide in two, just as they'd done when Henrietta was an embryo in her mother's womb.

Deborah and Zakariyya stared at the screen like they'd gone into a trance, mouths open, cheeks sagging. It was the closest they'd come to seeing their mother alive since they were babies.

After a long silence, Zakariyya spoke.

"If those our mother's cells," he said, "how come they ain't black even though she was black?"

"Under the microscope, cells don't have a color," Christoph told him. "They all look the same-they're just clear until we put color on them with a dye. You can't tell what color a person is from their cells." He motioned for Zakariyya to come closer. "Would you like to look at them through the microscope? They look better there."

Christoph taught Deborah and Zakariyya how to use the microscope, saying, "Look through like this ... take your gla.s.ses off... now turn this k.n.o.b to focus." Finally the cells popped into view for Deborah. And through that microscope, for that moment, all she could see was an ocean of her mother's cells, stained an ethereal fluorescent green.

"They're beautiful" she whispered, then went back to staring at the slide in silence. Eventually, without looking away from the cells, she said, "G.o.d, I never thought I'd see my mother under a microscope-I never dreamed this day would ever come."

"Yeah, Hopkins pretty much screwed up, I think," Christoph said.

Deborah bolted upright and looked at him, stunned to hear a scientist-one at Hopkins, no less-saying such a thing. Then she looked back into the microscope and said, "John Hopkin is a school for learning, and that's important. But this is my mother. n.o.body seem to get that."

"It's true," Christoph said. "Whenever we read books about science, it's always HeLa this and HeLa that. Some people know those are the initials of a person, but they don't know who that person is. That's important history."

Deborah looked like she wanted to hug him. "This is amazing," she said, shaking her head and looking at him like he was a mirage.

Suddenly, Zakariyya started yelling something about George Gey. Deborah thumped her cane on his toe and he stopped in midsentence.

"Zakariyya has a lot of anger with all this that's been goin on," she told Christoph. "I been trying to keep him calm. Sometime he explode, but he's trying."