"Anyway, after the bleeding stopped and I bandaged my finger, I started to give this idea some thought. I realized that the first thing I needed to do was make sure that I had the emotional arc or personal narrative that would drive the book. So the first step I took was to start looking back on my life and finding places where blood left a mark. Does that make sense?"
"From earliest childhood through adolescence and into adulthood I knew that I would write from the unique perspective of being an only boy in this devout Catholic household, growing up in close quarters with five sisters.
"I knew, inevitably, that I would write about the sister to whom I've always been closest, Shannon. She was a devoutly religious girl. So it was a natural way to tell that story of how blood plays such an important role in the Catholic sacrament. And we were a devout family. I was an altar boy. She was involved with the church.
"In working on the book I was constantly searching for different angles to come from. Whether it was science or history or looking at blood metaphorically, or looking at blood in terms of personal stories."
"Your writing about your involvement with the Roman Catholic church and transubstantiation and the Eucharist was interesting."
"This was belief that on one hand I once had taken for granted but also turned my back on, since I haven't been a practicing Catholic for many years. So it gave me a chance to dig into the history of the Catholic Church just in the specific circumstances of my own family."
"I got a kick out of the scenes," I said, "like those in Sleep Demons, when your dad would take you to do 'manly' things."
"Those scenes are so vivid in my memory. I had such a strong sense of how we were all one family and yet this feeling that I was being raised differently, that being a boy, and the only boy, was special. I was forbidden from doing the dishes or doing any housework. Of course, that made me just want to do housework. I used to go over to my friend Chris Porter's house and ask if I could wash the dishes with them, since all the Porter brothers had to do housework like my sisters did."
"There's something powerful in your particular story about being the only boy in the family. It can't keep itself out of a book."
"Exactly. But finding different ways to tell it, looking through the lens of blood, made it more challenging for me with this book."
"Did you come to understand all this business about mass cells and stem cells?"
"Somewhat. It took me a lot of time and research; as with my insomnia book, I approach science as a layperson. I began by reading. My great resource is the UCSF medical library -- both through contemporary books and textbooks and their Rare Books Room of 17th- through 19th-century books. Of course, I talked with doctors and scientists."
"Tell me the story of how blood cells are produced."
"There are stem cells in the bone marrow that --"
"And the bone marrow is like the marrow one digs from the bone with a marrow spoon?"
"Right. Bone marrow is a nursery for cells, these hot, dark, warm rooms where cells of different types are produced. Stem cells [an unspecialized cell that gives rise to a specific specialized cell] can produce different cells for different parts of the body. But some, for example, are genetically triggered to create red blood cells. It's in the bone marrow where these red blood cells are actually produced. Once they're at a certain stage, the red cells squeeze through the bone itself, and in the process they rid themselves of the nucleus, which is sort of the brains of the operation [a red blood cell in the blood of vertebrates transports oxygen and carbon dioxide to and from the tissues. In mammals, the red blood cell is disk-shaped and biconcave, contains hemoglobin, and lacks a nucleus]. That's why red blood cells, unlike white blood cells and most other cells of the body, do not have a nucleus and thus do not carry DNA."
"They're not big thinkers."
"They're not big thinkers. Sometimes they are called 'dumb cells' because they don't have those brains. White cells are different [any of the colorless or white cells in the blood that have a nucleus and cytoplasm and help protect the body from infection and disease through specialized neutrophils, lymphocytes, and monocytes. Also called leukocyte, white cell, white corpuscle]. White cells have DNA. They're much smarter in that way; they're the army of the blood who go out and fight infections and viruses. But their smartness is also a liability because it is in the nucleus that a virus, like HIV, for example, can then hijack and take over to produce its own millions of copies of its virus."
"Like a computer worm."
"Exactly. So learning things like that, for this book, was fascinating to me."
"So the red blood cells clean the blood?"
"Red blood cells carry oxygen to all the cells of the body. The hemoglobin that's part of the red blood cell is literally a working pigment."
"It's the chlorophyll."
"Yes. It's the equivalent to the green in plants. It carries the oxygen to all the body cells. Once it's deposited its oxygen, it picks up waste and carbon dioxide in return and makes its way through the veins, back to the lungs. It travels in circuits throughout the body for about 120 days."
"I was surprised by that."
"All the different blood cells have life spans. Red blood cells live for about 120 days. And then sure enough, right around 120 days, they start to drop off, and their parts are efficiently recycled within the body by the spleen, and the parts of the cell that can be still used are sent back to the bone marrow."