Indeed, when I began dispensing poisons many years ago, I did not simply clear my shelves of all but arsenic and opium. I continued to keep the ingredients needed to remedy most afflictions, supplies as benign as clary or tamarisk. Just because a woman has rid herself of one malady—a devious husband, for instance—does not mean she is immune to all other maladies. My register was proof of it; interspersed among the deadly tonics were also many healing ones.

“And only girls come here,” the child said.

“Did your mistress tell you that, too?”

“Yes’m.”

“Well, she was not mistaken. Only girls come here.” With the exception of one long ago, no man had ever stepped foot in my shop of poisons. I only aided women.

My mother had held tight to this principle, instilling in me from an early age the importance of providing a safe haven—a place of healing—for women. London grants little to women in need of tender care; instead, it crawls with gentlemen’s doctors, each as unprincipled and corrupt as the next. My mother committed to giving women a place of refuge, a place where they might be vulnerable and forthcoming about their ailments without the lascivious appraisal of a man.

The ideals of gentlemen’s medicine did not align with my mother’s, either. She believed in the proven remedies of the sweet, fertile earth, not the schemes diagrammed in books and studied by bespectacled gentlemen with brandy on their tongues.

The young girl in my shop looked around, the light of the flame in her eyes. “How clever. I like this place, though it is a bit dark. How do you know when it is morning? There are no windows.”

I pointed at the clock on the wall. “There is more than one way to tell the time,” I said, “and a window would do me no service at all.”

“You must grow tired of the dark, then.”

Some days, I could not distinguish night from day, as I had lost the intuitive sense of wakefulness long ago. My body seemed always in a state of fatigue. “I am accustomed to it,” I said.

How strange it was, sitting across from this child. The last child to sit in this very room was me, decades ago, observing my own mother as she worked. But I was not this girl’s mother, and her presence began to pull at me in an uncomfortable way. Though her naivety was endearing, she was very young. No matter what she thought of my shop, she could not need anything else I dispensed—the fertility aids, the cramp barks. She was here only for poison, so I aimed to bring us back to the subject at hand. “You have not touched your hot brew.”

She looked at it skeptically. “I do not mean to be rude, but Mrs. Amwell told me to be very careful—”