It didn’t take Mrs Lyndsay laid out on the floor and Jarvis worried he had killed her for Raven to side with Snow in believing that powerful agents should not be treated lightly. Raven had seen what alcohol did to his father. It was the magic potion that effected an unfailing transformation from merely a selfish philanderer into an angry brute, and the man would surely have killed his mother but for Raven’s intervention.

He had been only twelve years of age at the time. Raven had saved her life, but what that night had witnessed was a burden no child should have to carry.

The experience had in its own way transformed him. In a world where it seemed easy to serve injury and lay waste, he had made it his vocation to heal. In Dr Simpson he believed he had found the perfect teacher: a man driven by the stated desire to alleviate pain and suffering. But was his mentor falling to a different form of intoxication, deriving from the power of that which he had discovered? He had never struck Raven as a seeker of fame, but the goddess of reputation ruled over the field of medicine with a capricious hand, and there were few who did not relish the gilding of renown when it was bestowed upon them. If chloroform took Dr Simpson’s name with it across the world, would that affect his judgment when it came to its safety?

He turned from the window and looked around the room. Dr Simpson’s desk was piled high with papers and books, lecture notes were strewn about, and amid all of this sat an unfinished letter. The last sentence was abandoned halfway through, ink dripping onto the paper from the nib of a discarded pen. The appointing of Mr Quinton as secretary had made little impact here.

The letter was addressed to Robert Christison, Professor of Materia Medica and Therapeutics at the university. Raven read the line ‘… the discovery of a large effusion of blood upon the bed of our lamented patient …’, and fully intended to read further, but heard someone approaching and so he stood back, turning towards the window again.

The door to the study opened and the professor entered carrying more papers and a large leather-bound volume which he dumped heedlessly into the middle of his overcrowded desk.

‘Come away now, we must get on,’ he said. He looked at Raven, his brow furrowed. ‘Are you ready?’

‘Of course,’ Raven replied with conviction. ‘I am familiar with the procedure. I imagine it will have to be repeated several times.’