‘Oh?’ Cooper hadn’t expected to be presented with such an immediate image of the professor handling a dead body.

‘Glycerine softens the tissues and reduces fluid loss. An antibacterial substance like phenol prevents breakdown by micro-organisms.’

‘It delays decomposition, in other words.’

‘Indeed. What embalming really does is coagulate the body’s proteins, temporarily hardening and preserving. The work of the embalmer is the art of denial, the creation of an illusion. The body is drained, stuffed and painted for its final performance.’

Drained, stuffed and painted. Cooper filed that expression away in his memory.

‘I wonder if you know a place called Alder Hall, sir? It’s in the Wye Valley, not far from Edendale.’

‘I believe I know the name. Now, in what connection would I have heard of Alder Hall?’

‘There’s a collection of bones. Below the hall, in a crypt.’

‘Ah. Civil War relics?’

‘Yes, sir. Have you ever visited?’

‘No, I don’t believe so. What’s the name of the family?’

‘Saxton. What about a lady called Madeleine Chadwick, then? She’s the last of the Saxtons.’

Robertson shook his head. ‘I don’t quite see…’

‘What can you tell me about ossuaries?’ said Cooper. ‘Is that the right name for places where bones were kept?’

‘Yes, but the Alder Hall crypt isn’t an ossuary, is it? As I recollect, the bones were found elsewhere.’

‘Yes, sir.’

Robertson waited for him to explain, but Cooper remained silent. He was anticipating that the professor wouldn’t be able to tolerate silence, and would feel obliged to fill it with the sound of his own voice.

‘A lot of ossuaries came about where there was a shortage of suitable ground for burials,’ said Robertson, sitting back in his chair. ‘When you died, you might only be allowed to occupy your grave for a year or two, then you’d be dug up so that someone else could have your spot. The remains could mount up in vast numbers. Families would sometimes visit the bones of their dead relatives each year and wrap them in fresh cloths as long as they retained some flesh. Of course, decomposition takes place four times faster in the air. Burial simply slows the process down.’

Cooper thought of the first messages from their mystery caller. He’d referred to decomposition several times. The scented, carnal gardens of decomposition. He knew all about the processes of decay.

And now Robertson was watching him. Not for the first time, Cooper felt the professor might be able to read his thoughts.

‘But what about the smell?’ he said.

Robertson looked pleased. For a moment, Cooper thought the professor was going to nudge him in the ribs, like a bar-room comedian. Wink, wink, say no more.