“Berkeley knows more about this than he is telling us,” said Jervis.  “Let us look up the report and see who this stranger is.”  He took down from a shelf a large volume of newspaper-cuttings and laid it on the table.

“You see,” said he, as he ran his finger down the index, “Thorndyke files all the cases that are likely to come to something, and I know he had expectations respecting this one.  I fancy he had some ghoulish hope that the missing gentleman’s head might turn up in somebody’s dust-bin.  Here we are; the other man’s name is Hurst.  He is apparently a cousin, and it was at his house that the missing man was last seen alive.”

“So you think Mr. Hurst is moving in the matter?” said Thorndyke, when he had glanced over the report.

“That is my impression,” I replied, “though I really know nothing about it.”

“Well,” said Thorndyke, “if you should learn what is being done and should have permission to speak of it, I shall be very interested to hear how the case progresses; and if an unofficial opinion on any point would be of service, I think there would be no harm in my giving it.”

“It would certainly be of great value if the other parties are taking professional advice,” I said; and then, after a pause, I asked:  “Have you given this case much consideration?”

Thorndyke reflected.  “No,” he said, “I can’t say that I have.  I turned it over rather carefully when the report first appeared, and I have speculated on it occasionally since.  It is my habit, as Jervis was telling you, to utilise odd moments of leisure (such as a railway journey, for instance) by constructing theories to account for the facts of such obscure cases as have come to my notice.  It is a useful habit, I think, for, apart from the mental exercise and experience that one gains from it, an appreciable proportion of these cases ultimately come into my hands, and then the previous consideration of them is so much time gained.”

“Have you formed any theory to account for the facts in this case?” I asked.

“Yes; I have several theories, one of which I especially favour, and I am waiting with great interest such new facts as may indicate to me which of these theories is probably the correct one.”

“It’s no use your trying to pump him, Berkeley,” said Jervis.  “He is fitted with an information-valve that opens inwards.  You can pour in as much as you like, but you can’t get any out.”

Thorndyke chuckled.  “My learned friend is, in the main, correct,” he said.  “You see, I may be called upon any day to advise on this case, in which event I should feel remarkably foolish if I had already expounded my views in detail.  But I should like to hear what you and Jervis make of the case as reported in the newspapers.”

“There now,” exclaimed Jervis, “what did I tell you?  He wants to suck our brains.”

“As far as my brain is concerned,” I said, “the process of suction isn’t likely to yield much except a vacuum, so I will resign in favour of you.  You are a full-blown lawyer, whereas I am only a simple G.P.”