‘No. I am recently returned from studies abroad and have accepted the position of assistant to Dr Simpson. However, there is a matter that is troubling me, as I am concerned that I might be tainted by association. News comes to me of a patient of Dr Simpson’s who died, and I believe there is some controversy over his treatment of her.’

‘Indeed. A most disreputable affair. One does not like to impugn the judgment of a fellow practitioner, but it appears Dr Simpson might have been gravely at fault.’

‘Can you tell me how?’

‘He conducted a procedure that went badly wrong, and there was haemorrhage. The mattress was soaked in blood.’

‘How awful. Where did you see this mattress? Did you visit the house?’

‘No. But I spoke to the upholsterer who took it away.’

‘Is it possible he exaggerated, or misremembered? Lay people can be easily shocked by a little blood and imagine it to be a great deal more.’

‘He told us the mattress was soaked, and yet Simpson claimed there was very little blood. I find the inconsistency highly suspicious.’

‘But presumably you had reason to enquire about the mattress because of some other aspect of the case?’

‘Indeed. Professor Syme carried out a similar procedure on the patient with no such dire complications as were precipitant from Simpson’s work. Mrs Johnstone died three days after Simpson left her. It appears obvious he botched the operation and has sought to conceal the truth of it.’

Raven was bemused by Duncan’s mention of truth. He and Professor Miller were effectively in conspiracy, as they were both lying about what the upholsterer had told them.

‘It is a pity there was no post-mortem examination,’ Raven suggested.

‘I find that highly suspicious also,’ Duncan replied with great vehemence.

Raven had dangled this before him for a purpose, and he had seized upon it, confirming what he suspected. They had nothing else.

‘I gather you and Dr Simpson have had an unfortunate parting of the ways during my time abroad.’

‘His conduct has been unconscionable, and I would thus warn you to be wary if you are working for him. He has been striving to make his name synonymous with chloroform and chloroform synonymous with his name. He is bent on erasing my part in its discovery.’

Raven would have to concede that there was some truth to this. Despite Sarah’s unshakable faith in Dr Simpson’s righteousness, Raven knew that all medical men sought recognition, and were disinclined to share the glory when it shone upon them.

‘The world ought to know that it was I who suggested and produced the sample we used in its discovery. I had been experimenting for months, trying all manner of compounds and mixtures.’