He was as dreary and as lean as ever. His eyes had not lost their old trick (so subtly noticed in Betteredge's Narrative) of `looking as if they expected something more from you than you were aware of yourself.' But, so far as dress can alter a man, the great Cuff was changed beyond all recognition. He wore a broad- brimmed white hat, a light shooting-jacket, white trousers, and drab gaiters. He carried a stout oak stick. His whole aim and object seemed to be to look as if he had lived in the country all his life. When I complimented him on his Metamorphosis, he declined to take it as a joke. He complained, quite gravely, of the noises and the smells of London. I declare I am far from sure that he did not speak with a slightly rustic accent! I offered him breakfast. The innocent countryman was quite shocked. His breakfast hour was half-past six--and he went to bed with the cocks and hens!

`I only got back from Ireland last night,' said the Sergeant, coming round to the practical object of his visit, in his own impenetrable manner. `Before I went to bed, I read your letter, telling me what has happened since my inquiry after the Diamond was suspended last year. There's only one thing to be said about the matter on my side. I completely mistook my case. How any man living was to have seen things in their true light, in such a situation as mine was at the time, I don't profess to know. But that doesn't alter the facts as they stand. I own that I made a mess of it. Not the first mess, Mr. Blake, which has distinguished my professional career! It's only in books that the offices of the detective force are superior to the weakness of making a mistake.'

`You have come in the nick of time to recover your reputation,' I said.

`I beg your pardon, Mr. Blake,' rejoined the Sergeant. `Now I have retired from business, I don't care a straw about my reputation. I have done with my reputation, thank God! I am here, sir, in grateful remembrance of the late Lady Verinder's liberality to me. I will go back to my old work--if you want me, and if you will trust me--on that consideration, and on no other. Not a farthing of money is to pass, if you please, from you to me. This is on honour. Now tell me, Mr. Blake, how the case stands since you wrote to me last.'

I told him of the experiment with the opium, and of what had occurred afterwards at the bank in Lombard Street. He was greatly struck by the experiment--it was something entirely new in his experience. And he was particularly interested in the theory of Ezra Jennings, relating to what I had done with the Diamond after I had left Rachel's sitting-room, on the birthday night.

`I don't hold with Mr. Jennings that you hid the Moonstone,' said Sergeant Cuff. `But I agree with him, that you must certainly have taken it back to your own room.'

`Well?' I asked. `And what happened then?'

`Have you no suspicion yourself of what happened, sir?'

`None whatever.'

`Has Mr. Bruff no suspicion?'

`No more than I have.'

Sergeant Cuff rose, and went to my writing-table. He came back with a sealed envelope. It was marked `Private'; it was addressed to me; and it had the Sergeant's signature in the corner.

`I suspected the wrong person, last year,' he said: `and I may be suspecting the wrong person now. Wait to open the envelope, Mr. Blake, till you have got at the truth. And then compare the name of the guilty person, with the name that I have written in that sealed letter.'

I put the letter into my pocket--and then asked for the Sergeant's opinion of the measures which we had taken at the bank.