She looked back towards shore. ‘He sleepin now. Ol’ fella sure rile im up, but. You lot get long time way from here. That ship gone now, see. Wan’t us, wan’t our island. Understand?’

I nodded. She climbed over the bulwark and was about to turn and descend the ladder when she looked back one final time.

‘Don’t come back ere.’

And she was gone. The doctor re-latched the chest and picked it up by its inlaid handles. ‘This is your business, I suppose. I shall place it by your father’s bed.’

I thought he was going to leave and I did not want him to. ‘Tell me what happened with that family.’

He put the chest down, smiled vaguely. ‘Family?’

‘The ones who were ill. You told them the problem was their lack of piety.’

‘Yes?’

I sensed he knew where I was headed with this but wanted me to ask. ‘You are not religious, Doctor Gideon. Truthfully now, what was the problem?’

‘Ah.’ He smiled more directly and I loved the curl of his cheek where it met his mouth. ‘I had a suspicion as soon as we arrived, when they said the harvest had been late and the season cold. The grain they had in storage had purple kernels in it.’

He watched me, all theatre now.

‘St Anthony’s Fire,’ he said. ‘Causes gangrene, fitting, madness. The more they ate, the worse it would have got. The others on the island had accidentally quarantined themselves from the real problem, the grain, by exiling the false problem, the people. It’s not remotely contagious, even though it looks appalling. And once they stop eating the grain, they’ll recover swiftly. Marvellous, no?’

‘Then why did you rebuke them so about their observance?’

He shook his head. ‘They’re New Church. Swedenborgians. They do not subscribe to science. Had I said to them, You have made a fundamental error in your handling of the grain and now it is infected with a blight which is harming you they would have been indignant. Most likely they would have sent me on my way and thought us fools, and the problem would have persisted. So I appealed to their belief system: they took fright and will now do exactly as I told them. Burning everything that had been contaminated by the blight is not a perfect antidote, but it fits with their infernal understanding of misfortune, so they will carry it out faithfully.’

‘The livestock? The boy’s pet hen?’

‘Unfortunate, but consistent with the necessary awe.’

‘You lied to them.’ Was I really arguing with him, or just… sparring? I no longer knew. But I saw the boy’s face, his pride in that hen, and I turned away from the memory.

‘I persuaded them, and they will benefit.’