Finally, however, my supply of anecdotes ended and I asked him to what I owed the honour of his visit.

'I wish to redraft my will,' he told me. I let loose the breath I had been holding. This was a much more ordinary request than I had been expecting, and my relief was palpable.

He continued, 'I wish to add clauses that would cater for any extended disappearances or absences of mine. If this should happen, I would like to appoint another man to step into my shoes and adopt all my responsibilities and assets.'

Like the punch which follows a clever feint, this statement took the wind from me. What he was proposing was that he give total power over him to another person. Why, with such a provision, if the person named were untrustworthy, they could kidnap Doctor Jekyll, or even kill him and then benefit from all the doctor's wealth. The only way I would ever agree to such a provision would be if the person named was known to me - or in fact if they were me.

'Which man would you bestow such a bequest upon?' I finally managed to ask.

'He is unknown to you, I believe: a man by the name of Edward Hyde.'