Deirdre knew a great deal about me, including the obvious facts: That, for a while, we’d worked in the same field of science, almost but not quite (we’d chosen different techniques to study the same problem) competing with each other. That just when I was becoming famous I left my lab to return to the village in central New York where I’d grown up, and where I taught high school for twenty-five years. I also wrote brief biographies, many for young readers, of women scientists: Dorothy Hodgkin, Rosalind Franklin. Barbara McClintock, Lucy Say. Later, when that sort of work grew more fashionable, I began writing magazine articles and then longer works for adults interested in science. I’d had a small success (the illustrations were lovely) with an overview of nineteenth-century women naturalists who, like Julia Ballard, specialized in moths and butterflies.

Deirdre knew all of this and more, but, as I reminded myself while she washed her hands, she’d still missed a lot. As I’d missed crucial things about her. She left the kitchen without touching anything, every surface apparently contaminated by the bottled mouse, and I poured the water and let the leaves and flowers steep. Then I brought the pot, along with the sugar Deirdre had forgotten about, back to the porch, where the tea glowed like rubies in the afternoon light. As I poured, she said, “I’m sorry about the school closing down.”

“I was going to retire anyway,” I said, adding, when she looked skeptical, “Really. I might have waited a few more years, but it was time, and I’ve saved some money. I’ll be fine. It’s terrible for the younger teachers, though. And for the village.”

“All those students,” she said. “Where will they go? If you and your sister were young now . . .”

“We would have been lost,” I agreed. We talked for a minute about centralized school districts and school taxes, nothing very interesting, and then I asked about her work, and about her travels, and, cautiously, about her health. She was better, she claimed. Much better; and it seemed as though after all she’d have some years. Later we went for a walk, winding along the thin paths I’d traced through woods that were not legally mine but were close to abandoned. A little fox made his way up a cliff when he saw us, bits of shale falling as he leapt from layer to layer. A quail shot into the air. At the edge of a neighbor’s pond, a young heron stabbed at a frog and missed, as if he didn’t yet understand how the surface bent the light and made everything shift position. Deirdre, brushing at a cinnamon fern, said, “Would you come on Wednesday night? Sayeed wants me to talk about the early days of ubiquitin, since that’s the topic this summer—”

“The new director?” I asked.