I turned towards the student who had whistled. I would have struck him, given the chance. God knows what my face must have told him, because he recoiled in horror and my blow missed him. I grasped him by the shoulders and thrust him aside, bruising him I’m sure, and then I was running down the stairs and out into the street, gasping for the town air that suddenly seemed blessedly cool and clean and fresh, heaving as though I would never fill my lungs with enough of it. I was coughing and gasping, striving to shift the stench of mortality that filled my nostrils at the sight of my darling Jenny, lying on that slab, stone cold and naked, exposed for all to see.

It was a sight that I would never ever be rid of again.

I could feel the tears starting in my eyes and the revulsion that rose from my stomach into my throat and made me want to vomit. But no sooner did I get command of myself with some monumental effort than I was aware of Thomas beside me. He too was weeping, sobbing and choking. Indeed he was so unlike himself that in the middle of my own horror, I found myself wondering if he might be having a seizure.

‘Jenny, Jenny, Jenny,’ he kept saying.

It was true then, and not some terrible figment of my imagination. It had been Jenny, there on the slab, my Jenny, with the child still inside her, Jenny upon whom the professor had been about to demonstrate his brutal procedure, slitting her open, for the edification of a group of careless students and the entertainment of a handful of men about town.

‘I knew nothing!’ he was saying. ‘Oh, William, I swear I knew nothing until you told me! Why didn’t she come to me? Why didn’t she tell me? Why? Why? Dear God, she should have told me!’

I looked at his tormented face. I saw the tears streaming down and the colour all gone, except for two bright spots of red on his cheeks. He had his hands over his mouth and he was retching. And then he leaned against the outer wall of the dissecting rooms and threw his head back against the stones, banging his skull there, until you could see a patch of blood and hair on the stone.

I put my hand out to him in alarm at his vehemence. ‘Stop it!’ I said. ‘Stop it, Thomas! You’re wounding yourself!’

‘I should do more than wound myself! It’s my fault. Dear God, man, don’t you see? It’s my fault! God help me, what have I done? What have I done!’

I looked at him again and a dreadful calm came upon me. I had a sudden bizarre thought that it was like Mr Caddas’s weaving loom when everything fell into place and the true pattern emerged from the confusion of flying shuttles and coloured wools. The scales fell from my eyes and I saw just what a fool I had been. I had assumed – with no evidence of any other liaison – that the father of Jenny’s child was some weaver, perhaps a married man, and that was why she would not name him. Well, I had been right in one particular at least. He was a married man. I thought of all those occasions when Jenny had been invited to stay at Thomas’s house to do this or that piece of work: the dress for Marion, the drapes for the bedroom, the waistcoat for Thomas. I thought of his charm, and the attention he had paid to her. I thought of how his attention had made me feel, how I would have done almost anything to please him. How flattering it must have been for a young woman like Jenny! I saw it all with astounding clarity: Thomas, casually enchanting her. My Jenny, adoring him, following wherever he led her.

When had he first taken her to his bed I wonder? Had it been often, or only one lapse? I knew that Marion went to Edinburgh to visit her family, taking the children with her. Had there been occasions when he had contrived to be in the house overnight at the same time as Jenny, with his wife absent? There were other servants in the house, of course, but that made it look all the more respectable. If he was circumspect, nobody would have suspected. Jenny herself had told me how they were so kind, the Browns, because they gave her a bed chamber of her own, a small room with its own fireplace and a good fire to keep her warm in the evenings, even though she would have expected to be sharing one of the maids’ rooms up in the attic with the other lassies.

It flashed before my eyes in an instant. Jenny had been carrying Thomas’s child. By the time he found out, she had been away to Dumfries and – what seems so much worse to me now – he had taken the decision to do nothing about it. When she went missing he had deluded himself into thinking that she had found shelter elsewhere. He must have been worried that she would return with or without the child. And equally worried that she would not return at all. But perhaps he had hoped that she would return with the child, that I would do as he expected (he knew me, to that extent, better than I knew myself), would find it in my heart to take Jenny in marriage and bring up the child as my own.

What he had not expected, of course, was that in her desperation and misery, she would leave Dumfries and come back to Glasgow, seeking the father, intending perhaps to throw herself on his mercy. God knows what would have happened if she had reached her destination. Would Jenny have confessed all to Marion? Would she have been believed? Would Thomas have managed to intercept her? And what then? Maids who ‘got themselves into trouble’ (a curious expression with a flavour of impossibility about it) were seldom believed when they named the fathers of their ill-gotten weans, particularly when those fathers were gentlemen. It would have been easier for Marion to believe me to be the culprit in spite of my protestations of innocence.

But then it struck me that what was commonplace – and deemed to be generous – was for the gentleman in question to arrange a marriage with some trusted servant and set the young couple up with a good dowry. Sometimes the child might be fed and clothed and educated as well. I have no doubt at all that, even if Jenny had turned up at his door in her shift, this is exactly what Thomas would have done. Marion would have been hurt and angry but she would have accepted the situation. I saw all too clearly that I would have been cast in the role of trusted servant. I would undoubtedly have married Jenny. But the friendship between Thomas and me would have been damaged beyond repair, and I think he knew that too and wished to avoid it, if at all possible.

Eventually I found out a few more details of her death, although even reading about them was painful beyond belief. The journey back to Glasgow had taken her a very long time and who knew what privations she had suffered along the way? She had fetched up at the door of a house of correction, not too far from Thomas’s house, exhausted and in pain. I managed to establish this much later, writing to Professor Jeffray for such information as he could give me. He replied soberly, with kindness even, offering no false solace where none was to be had, and I respected him for that, ever afterwards. He was a better and much more compassionate man than I had given him credit for. She had gone into labour with the child, dying of exhaustion and shock before she could even give birth and taking her unborn infant with her. The correction house had contacted the professor, who had asked them to keep an eye out for just such a ‘specimen’ – a woman dying in late pregnancy or early childbirth, upon whom he might demonstrate the efficacy of his chain saw in the terrible process of symphysiotomy. The infant had been a girl. I hadn’t asked, hadn’t wished to know, but Jeffray had mentioned it himself in his letter, referring to Jenny and the child as ‘the mother and her baby girl’ without further explanation.

But all that came much later. For the moment, I could see only that I had been cruelly betrayed by the best friend I ever had. The realisation struck me like a physical pain, like a blow to the chest. Thomas stretched out his hand to me, but I cast him off and then – because I really think I might have killed him if I had stayed – I ran away into the streets of the town and down towards the river. I came to myself only much later on that day, in the countryside where I had been wont to gather specimens for him, sitting on a stone beside the burn where we had once guddled for trout and weeping as if my very heart were broken.