Christopher put the child down.

“What happened?”

Christopher was a strong man in a panic, and he spoke in a strangely high-pitched voice. “She stumbled in my workshop and fell with her arm against a bar of red-hot iron. Do something for her, quickly, sister, she’s in such agony!”

Caris touched the child’s cheek. “There, there, Minnie, we’ll ease the pain very soon.” Poppy seed extract was too strong, she thought: it might kill such a small child. She needed a milder potion. “Nellie, go to my pharmacy and fetch the jar marked ‘Hemp essence’. Walk quickly, but don’t run – if you should stumble and break the vial, it will take hours to make up a new batch.” Nellie hurried away.

Caris studied Minnie’s arm. She had a nasty burn but, fortunately, it was restricted to the arm, nothing like as dangerous as the all-over burns people got in house fires. There were large angry blisters over most of the girl’s forearm, and in the middle the skin was burned away to reveal charred flesh underneath.

She looked up for help and saw Mair. “Go to the kitchen and get me half a pint of wine and the same quantity of olive oil, in two separate jugs, please. Both need to be warm but not hot.” Mair left.

Caris spoke to the child. “Minnie, you must try to stop screaming. I know it hurts, but you need to listen to me. I’m getting you some medicine. It will ease the pain.” The screaming abated somewhat, and began to turn into sobbing.

Nellie arrived with the hemp essence. Caris poured some on to a spoon, then thrust the spoon into Minnie’s open mouth and held her nose. The child swallowed. She screamed again, but after a minute she began to calm down.

“Give me a clean towel,” Caris said to Nellie. They used a lot of towels in the hospital, and the cupboard behind the altar was always full of clean ones, by Caris’s edict.

Mair came back from the kitchen with the oil and wine. Caris put a towel on the floor beside Minnie’s mattress, and moved the burned arm over the towel. “How do you feel?” she asked.

“It hurts,” Minnie wailed.

Caris nodded in satisfaction. Those were the first coherent words the patient had uttered. The worst was over.

Minnie began to look sleepy as the hemp took effect. Caris said: “I’m going to put something on your arm to make it better. Try to keep still, will you?”

Minnie nodded.

Caris poured a little of the warm wine on to Minnie’s wrist, where the burn was least bad. The child flinched, but did not try to snatch her arm away. Encouraged, Caris slowly moved the jug up the arm, pouring the wine over the worst of the burn to cleanse it. Then she did the same with the olive oil, which would soothe the place and protect the flesh from bad influences in the air. Finally she took a fresh towel and wrapped it lightly around the arm to keep the flies off.

Minnie was moaning, but half asleep. Caris looked anxiously at her complexion. Her face was flushed pink with strain. That was good – if she had been turning pale, it would have been a sign that the dose had been too strong.

Caris was always nervous about drugs. The strength varied from batch to batch, and she had no precise way of measuring it. When weak, the medicine was ineffectual; when strong, dangerous. She was especially frightened of overdosing children, though the parents always pressured her for powerful medicine because they were so distressed by their children’s pain.

At that point Brother Joseph came in. He was old, now – somewhere in his late fifties – and all his teeth had fallen out, but he was still the priory’s best monk-physician. Christopher Blacksmith immediately leaped to his feet. “Oh, Brother Joseph, thank God you’re here,” he said. “My little girl has a terrible burn.”

“Let’s have a look,” said Joseph.

Caris stood back, hiding her irritation. Everyone believed the monks were powerful doctors, able to work near-miracles, whereas the nuns just fed the patients and cleared up. Caris had long ago stopped fighting that attitude, but it still annoyed her.

Joseph took off the towel and looked at the patient’s arm. He prodded the burnt flesh with his fingers. Minnie whimpered in her drugged sleep. “A bad burn, but not fatal,” he said. He turned to Caris. “Make up a poultice of three parts chicken fat, three parts goat dung and one part white lead, and cover the burn with it. That will bring forth the pus.”

“Yes, brother.” Caris was doubtful of the value of poultices. She had noticed that many injuries healed well without bringing forth the pus that monks thought such a healthy sign. In her experience, wounds sometimes became corrupt beneath such ointments. But the monks disagreed – except for Brother Thomas, who was convinced he had lost his arm because of the poultice prescribed by Prior Anthony almost twenty years ago. However, this was another battle Caris had given up. The monks’ techniques had the authority of Hippocrates and Galen, the ancient writers on medicine, and everyone agreed they must be right.

Joseph left. Caris made sure that Minnie was comfortable and her father was reassured. “When she wakes up, she will be thirsty. Make sure she gets plenty to drink – weak ale or watered wine.”

She was in no hurry to make the poultice. She would give God a few hours to work unaided before she began Joseph’s treatment. The likelihood that the monk-physician would come back later to check on his patient was small. She sent Nellie out to collect goat dung from the green to the west of the cathedral; then she went to her pharmacy.

It was next to the monks’ library. Unfortunately, she did not have large windows matching those in the library. The room was small and dark. However, it had a workbench, some shelves for her jars and vials, and a small fireplace for heating ingredients.

In a cupboard she kept a small notebook. Parchment was expensive, and a text block of identical sheets would be used only for holy scriptures. However, she had gathered a stack of odd-shaped offcuts and sewn them together. She kept a record of every patient with a serious complaint. She wrote down the date, the patient’s name, the symptoms and the treatment given; then later she added the results, always noting exactly how many hours or days had passed before the patient got better or worse. She often looked back over past cases to refresh her memory on how effective different treatments had been.

When she wrote down Minnie’s age, it occurred to her that her own child would have been eight this year, if she had not taken Mattie Wise’s potion. For no good reason, she thought her baby would have been a girl. She wondered how she would have reacted if her own daughter had suffered an accident. Would she have been able to deal so coolly with the emergency? Or would she have been almost hysterical with fear, like Christopher Blacksmith?

She had just finished logging the case when the bell rang for evensong, and she went to the service. Afterwards it was time for the nuns’ supper. Then they went to bed, to get some sleep before they had to rise for Matins at three o’clock in the morning.

Instead of going to bed, Caris went back to her pharmacy to make the poultice. She did not mind the goat’s dung – anyone who worked in a hospital saw worse things. But she wondered how Joseph could imagine it was a good thing to put on burned flesh.

She would not be able to apply it until morning, now. Minnie was a healthy child: her recovery would be well advanced by then.

While she was working, Mair came in.

Caris looked at her curiously. “What are you doing out of bed?”

Mair stood beside her at the work bench. “I came to help you.”

“It doesn’t take two people to make a poultice. What did Sister Natalie say?” Natalie was the sub-prioress, in charge of discipline, and no one could leave the dormitory at night without her permission.

“She’s fast asleep. Do you really think you’re not pretty?”