with extraordinary quickness and energy by our opponent, we have betrayed ourselves and lost our man.

We had been sauntering slowly down Regent Street during this conversation, and Dr. Mortimer, with his companion, had long vanished in front of us.

There is no object in our following them, said Holmes. The shadow has departed and will not return. We must see what further cards we have in our hands and play them with decision. Could you swear to that man's face within the cab?

I could swear only to the beard.

And so could I -- from which I gather that in all probability it was a false one. A clever man upon so delicate an errand has no use for a beard save to conceal his features. Come in here, Watson!

He turned into one of the district messenger offices, where he was warmly greeted by the manager.

Ah, Wilson, I see you have not forgotten the little case in which I had the good fortune to help you?

No, sir, indeed I have not. You saved my good name, and perhaps my life.

My dear fellow, you exaggerate. I have some recollection, Wilson, that you had among your boys a lad named Cartwright, who showed some ability during the investigation.

Yes, sir, he is still with us.

Could you ring him up? -- thank you! And I should be glad to have change of this five-pound note.