Free Keeper: One House, Three Generations, and a Journey Into Alzheimer's by Andrea Gillies Page B

others. Your body may be a temple but it’s also, far more intriguingly, a laboratory within which chemical reactions are ongoing.
    The resting potential of a cell is created by potassium leaking out of it. There’s a high concentration of potassium inside cells, and a weak solution of it outside, where there’s a high concentration of sodium. The potassium flowing out of a cell creates a negative charge (–70 millivolts). That’s the resting potential of a cell. Along comes electrical information—from a pain in your leg, say, or something seen, or something learned, or a memory—and astoundingly, it seems that the information in every case is of the same order; it’s just the question of where it comes from and where it’s directed in the brain that translates it into pain, vision, knowledge, recall. What happens is that the sodium outside the cell flows in through a hinged gate, creating a wave of positive charge, which happens to be 110 millivolts, so that the balance from the original ‒70 is +40 millivolts. Sodium flows in, potassium flows out: It takes about a thousandth of a second. The electrical charge passes to the next excited cell, and onward in waves, at fantastic speeds. After the sodium/potassium exchange has occurred, a protein inside the cell is responsible for ushering out the excess sodium, chaperoning back the potassium, so that the cell is reduced to its usual state, ready for the next impulse (which is called an action potential) .
    All this was confirmed, incidentally, by Alan Hodgkin and Andrew Huxley’s research using the squid, which has a giant axon, a millimeter thick and visible to the naked eye. They were awarded the Nobel Prize for their work in 1963. Hodgkin commented that the prize should have gone to the squid.

Chapter 5
Here reign the simplicity and purity of a primitive age, and a health and hope far remote from towns and cities .
    —H ENRY D AVID T HOREAU
    O UR FIRST BED-AND-BREAKFAST GUESTS ARRIVE, A foursome of young friends, three Scots and an Australian. It is a perfect golden day, windless and warm, and I serve their afternoon tea in the garden. As I’m handing out cups and setting down a plate of warm scones, I’m wondering what to say about Nancy. I may be guilty of being defensive about her. Should I warn people who come to stay about the potential for encounters with Alzheimer’s? That’s what is going through my mind as I pour tea. Nancy may well want to meet them. She’s at an insistently sociable stage. I put the teapot down, take a steadying breath, point out that I made the rhubarb jam, and leave them to it, Nancy’s name unspoken. It’s too difficult to pitch it. I need to give some thought to this.
    Later, I find the visitors gathered in the hall, looking very much as if they want to waylay somebody with a query. A question about eating: How do I rate the pubs in the village? Before I can answer, a hesitant voice says, “Hello?”
    “It’s all right, Nancy,” I say, “just houseguests.” And then, to our visitors, “This is Nancy, my mother-in-law.”
    “Hello, Nancy,” they chorus.
    “And how are you today?” the Australian asks her. “You have a beautiful house here. We’re just admiring the plaster-work.”
    Nancy, beaming, shuffles forward. Some days she has an old-lady gait, uncertain of her footing. She has her arms outstretched as she comes, grinning. “Oh, it’s you! Hello!” she cries to the Australian, and for a horrified moment I think she’s going to kiss him.
    “Let’s go into the morning room; this is where you’ll be having breakfast,” I say, taking Nancy’s hand and yanking her forward.
    “Oh, you’ll be comfortable in here,” Nancy assures the visitors. “This is my house, you know. I was born here. I’ve always lived here. My father is here, too. He’s in the garden. He doesn’t mean to be rude.” She smacks her lips together. “Well, I don’t know, actually. Perhaps he does.” She’s giggling