Thorndyke looked round to make sure that his henchman had departed, and said—
“A queer affair, Jervis; a very odd affair indeed. I was coming up from the Borough, picking my way mighty carefully across the road on account of the greasy, slippery mud, and had just reached the foot of London Bridge when I heard a heavy lorry coming down the slope a good deal too fast, considering that it was impossible to see more than a dozen yards ahead, and I stopped on the kerb to see it safely past. Just as the horses emerged from the fog, a man came up behind and lurched violently against me and, strangely enough, at the same moment passed his foot in front of mine. Of course I went sprawling into the road right in front of the lorry. The horses came stamping and sliding straight on to me, and, before I could wriggle out of the way, the hoof of one of them smashed in my hat—that was a new one that I came home in—and half-stunned me. Then the near wheel struck my head, making a dirty little scalp wound, and pinned down my sleeve so that I couldn’t pull away my arm, which is consequently barked all the way down. It was a mighty near thing, Jervis; another inch or two and I should have been rolled out as flat as a starfish.”
“What became of the man?” I asked, wishing I could have had a brief interview with him.
“Lost to sight though to memory dear: he was off like a lamplighter. An alcoholic apple-woman picked me up and escorted me back to the hospital. It must have been a touching spectacle,” he added, with a dry smile at the recollection.
“And I suppose they kept you there for a time to recover?”
“Yes; I went into dry dock in the O.P. room, and then old Langdale insisted on my lying down for an hour or so in case any symptoms of concussion should appear. But I was only a trifle shaken and confused. Still, it was a queer affair.”
“You mean the man pushing you down in that way?”
“Yes; I can’t make out how his foot got in front of mine.”
“You don’t think it was intentional, surely?” I said.
“No, of course not,” he replied, but without much conviction, as it seemed to me; and I was about to pursue the matter when Polton reappeared, and my friend abruptly changed the subject.
After dinner I recounted my conversation with Walter Hornby, watching my colleague’s face with some eagerness to see what effect this new information would produce on him. The result was, on the whole, disappointing. He was interested, keenly interested, but showed no symptoms of excitement.
“So John Hornby has been plunging in mines, eh?” he said, when I had finished. “He ought to know better at his age. Did you learn how long he had been in difficulties?”
“No. But it can hardly have been quite sudden and unforeseen.”
“I should think not,” Thorndyke agreed. “A sudden slump often proves disastrous to the regular Stock Exchange gambler who is paying differences on large quantities of unpaid-for stock. But it looks as if Hornby had actually bought and paid for these mines, treating them as investments rather than speculations, in which case the depreciation would not have affected him in the same way. It would be interesting to know for certain.”
“It might have a considerable bearing on the present case, might it not?”
“Undoubtedly,” said Thorndyke. “It might bear on the case in more ways than one. But you have some special point in your mind, I think.”
“Yes. I was thinking that if these embarrassments had been growing up gradually for some time, they might have already assumed an acute form at the time of the robbery.”
“That is well considered,” said my colleague. “But what is the special bearing on the case supposing it was so?”
“On the supposition,” I replied, “that Mr. Hornby was in actual pecuniary difficulties at the date of the robbery, it seems to me possible to construct a hypothesis as to the identity of the robber.”
“I should like to hear that hypothesis stated,” said Thorndyke, rousing himself and regarding me with lively interest.
“It is a highly improbable one,” I began with some natural shyness at the idea of airing my wits before this master of inductive method; “in fact, it is almost fantastic.”
“Never mind that,” said he. “A sound thinker gives equal consideration to the probable and the improbable.”
Thus encouraged, I proceeded to set forth the theory of the crime as it had occurred to me on my way home in the fog, and I was gratified to observe the close attention with which Thorndyke listened, and his little nods of approval at each point that I made.
When I had finished, he remained silent for some time, looking thoughtfully into the fire and evidently considering how my theory and the new facts on which it was based would fit in with the rest of the data. At length he spoke, without, however, removing his eyes from the red embers—
“This theory of yours, Jervis, does great credit to your ingenuity. We may disregard the improbability, seeing that the alternative theories are almost equally improbable, and the fact that emerges, and that gratifies me more than I can tell you, is that you are gifted with enough scientific imagination to construct a possible train of events. Indeed, the improbability—combined, of course, with possibility—really adds to the achievement, for the dullest mind can perceive the obvious—as, for instance, the importance of a fingerprint. You have really done a great thing, and I congratulate you; for you have emancipated yourself, at least to some extent, from the great fingerprint obsession, which has possessed the legal mind ever since Galton published his epoch-making monograph. In that work I remember he states that a fingerprint affords evidence requiring no corroboration—a most dangerous and misleading statement
