People did say, when photographs first appeared, that there was danger in having your image captured. Part of your soul would remain forever imprisoned in that glass lens. Sit for too many and you might be … depleted. More alive in the photograph than in real life.

She never suspected the same could be true with art, until now. For isn’t that what she has been trying to do: reduce someone to their essence, and capture it?

But Simon is staring at her with utter dismay. She has never seen him look so wretched, and she feels like a simpleton.

‘Oh dear. I can see from your expression that it is Kingsdown Lunatic Asylum for me.’

‘That is beneath you, Miss Darken.’

He did commit a patient to a madhouse once. A lady. He will not speak of it, he only tells her, darkly, never again. Whatever happened to her must have been terrible.

‘Simon,’ she says slowly. ‘If you truly will not consider me mad … Can you tell me what you think of Mesmerism?’

He blinks. ‘Mesmerism? Why?’

‘Is there a science to it?’

He wets his lips, seems to think. ‘Yes, I believe there may be. Not that it has been conclusively proven. They theorise that a vapour flows from every living thing, which a trained operator can manipulate. If he does so correctly, he may exert the power of his mind over another person’s body. I have seen a mesmerist put a patient into a trance and tell them that they will feel no pain. The patient then underwent a surgical procedure without making a sound of protest. Before we had ether and chloroform, it could be useful. Not that I ever practised it myself.’ A cloud passes over his face. ‘It struck me as distasteful to see a patient under the power of a stranger’s will. Entered and dominated, as if by a parasite …’ His gaze sharpens. ‘Have you been mesmerised, Miss Darken? Is that why you are asking me this?’ He leans down towards her so quickly that it startles her. ‘Is that what has happened? Tell me.’

‘No! It was only a question, and I do not know why you should be so nettled by it.’ She pulls away from him to the other side of the bed, spilling some of the flip. ‘I saw an advertisement in someone’s window, that’s all.’

‘Well, I’ – he tries to gather himself – ‘I am sorry. I spoke hastily. But you must understand that there are charlatans about. People who meddle with forces they should not. In the mesmeric trance, a person is subject to a lower and more automatic level of functioning. They are permitted – nay, encouraged – to renounce their consciousness and let their usual personality fade away. The brain is a powerful organ, Miss Darken, but delicate. One should not … tamper.’

‘And I expect you feel the same about Spiritualism?’

‘Good God! Is it possible you have been bitten by that nonsense?’