‘Yes, yes, I know,’ said Anton. ‘There’s so much here that fascinates me. So many mysteries to unfold.’

‘And what do you make of us all?’

There was something suggestive in her manner, though he had no idea what she meant. Perhaps she was flirting with him.

‘So many people,’ he said blandly. ‘The staff, the patients, the founders and their families. Their critics and admirers. Do you like working here?’

‘Oh, yes,’ said Johanna. ‘It was hard for my mother when my father was killed. We lived in Budapest before the war. But my mother found work in Graz and I like it here. I have a nice room and I’m friends with Lena. It’s very long hours, that’s all.’

‘You should join a trade union.’

‘It’s not Vienna.’

‘What about the patients? Do you mix with them?’

‘I see a lot of them. It doesn’t bother me. I think I’ll train to be a nurse one day.’

She stood staring at Anton, as though she expected more from him. He looked back to his papers.

‘I’ll come back for the tray.’

The following afternoon, after he had filled another notebook of his own, Anton came across a cardboard box that was unlike the others. Inside, tied up in string, were packets of letters, still in their original envelopes. All were addressed to Sonia, most from her husband, Jacques; some were from their son Daniel while a student at Cambridge and afterwards, when he was in the army, from Belgium and Italy; and a few were in the childish hands of their nieces, Martha and Charlotte.

Anton felt a quiver of unease at opening them, though the fact that they had been lodged in the archive presumably meant they were there to be read.

The run of letters that interested him most were from Jacques, who had crossed the United States by train in 1896 to visit Pasadena, where he was to inspect the scenic railway at Mount Lowe. The business of the trip was to report back on the feasibility of such a system for the lofty Wilhelmskogel, to whose summit the clinic was to move when its lease on the Schloss Seeblick ran out; but Jacques was also in some sort of emotional turmoil and there had been an element of compassionate leave or sabbatical about the venture.

The train went through frontier posts and one-horse towns that had clearly excited him, though not enough to overcome his anguish at his wife’s absence.