‘I, and Dr. Gourlay, and Professor Grant,’ the doctor named two celebrated Edinburgh specialists. ‘But just of late I would not be so certain.’

‘Then my theory need not necessarily be wrong?’

‘It can’t but be wrong. First, I saw the man dead.’

‘Absolute tests of death are hardly to be procured, of course you know that better than I do,’ said Merton.

‘Yes, but I am positive, or as positive as one can be, in the circumstances. However, that is not what I stand on. There was a witness who saw the marquis go.’

‘Go—how did he go?’

‘He disappeared.’

‘The body disappeared?’

‘It did, but you had better hear the witness’s own account; I don’t think a second-hand story will convince you, especially as you have a theory.’

‘Was the witness a man or a woman?’