Sarah made no reply and they walked on in silence. Raven had thought that his change of heart would begin to melt the frostiness that had developed between them, but it appeared that a thaw might be slow in coming.

‘How is Archie?’ he enquired, and instantly regretted it. He didn’t know how much her husband might have told Sarah about their conversation.

‘Why do you ask?’

She sounded defensive. Perhaps she was merely wary of his suspicions, what he might have picked up on, being a medical man.

‘Polite enquiry.’

Sarah seemed to realise she was being unnecessarily brusque.

‘He is well,’ she told him, her tone more even. ‘And what about you? Aside from a few dead leeches, are you glad to be back in Edinburgh?’

‘In some ways I am.’

He smiled at her, but her eyes were fixed ahead. She did not turn to look at him as he spoke.

‘I feel I learned a great deal abroad,’ he continued, ‘but in practical terms, little seems to have changed with regard to my duties. I have yet to make headway in establishing myself as an independent practitioner. Working with someone as esteemed as Dr Simpson, it is tantalising to see the rewards that are still so far out of my reach. For instance, a lady from Brighton has been sending letters begging for a consultation. The professor always refuses, saying that she is not ill and that he has told her as much. Yesterday she sent a telegram offering a fee of a thousand pounds. A thousand pounds! And still he refuses to consider it.’

He waited for Sarah to respond but she said nothing, her face partially hidden by the thick woollen scarf she had wrapped round it.

‘He said it would be better if she put her guineas into some struggling doctor’s pocket,’ he continued. ‘I thought: there is a struggling doctor not three feet from you, sir. Honestly, I couldn’t imagine ever being in a position to refuse such a sum. I’ve half a mind to go to Brighton myself.’

‘What’s stopping you?’ she asked.

‘I don’t have the money.’

Raven hadn’t intended it so, but he saw the joke when a hint of amusement finally appeared upon Sarah’s face.

‘Perhaps the doctor thinks he has wealth enough and his interests extend beyond lining his pockets,’ she said. Her tone was sincere, but from the look on her face he could tell that she was teasing him. ‘And the large fees he does collect allow him to treat those with nothing for nothing.’

‘He could certainly treat a great deal of them if he acquiesced to the Brighton lady’s wishes.’

Sarah rolled her eyes pityingly. Raven had to bite back a remark about her own new-found financial comfort.

As they neared the upholsterer’s, Sarah softened her voice, as though concerned about eavesdroppers.

‘Have you heard anything about money going missing? From Queen Street?’