"Don't let me interrupt you, Jervis," said he. "I will make myself a cup of tea while you finish your writing, and then you shall exhibit the day's catch and hang your nets out to dry."
I was not long in finishing my notes, for I was in a fever of impatience to hear Thorndyke's comments on my latest addition to our store of information. By the time the kettle was boiling my entries were completed, and I proceeded forthwith to retail to my colleague those extracts from my conversation with Juliet that I have just recorded.
He listened, as usual, with deep and critical attention.
"This is very interesting and important," he said, when I had finished; "really, Jervis, you are a most invaluable coadjutor. It seems that information, which would be strictly withheld from the forbidding Jorkins, trickles freely and unasked into the ear of the genial Spenlow. Now, I suppose you regard your hypothesis as having received very substantial confirmation?"
"Certainly, I do."
"And very justifiably. You see now how completely you were in the right when you allowed yourself to entertain this theory of the crime in spite of its apparent improbability. By the light of these new facts it has become quite a probable explanation of the whole affair, and if it could only be shown that Mr. Hornby's memorandum block was among the papers on the table, it would rise to a high degree of probability. The obvious moral is, never disregard the improbable. By the way, it is odd that Reuben failed to recall this occurrence when I questioned him. Of course, the bloody finger-marks were not discovered until he had gone, but one would have expected him to recall the circumstance when I asked him, pointedly, if he had never left bloody finger-prints on any papers."
"I must try to find out if Mr. Hornby's memorandum block was on the table and among the marked papers," I said.
"Yes, that would be wise," he answered, "though I don't suppose the information will be forthcoming."
My colleague's manner rather disappointed me. He had heard my report with the greatest attention, he had discussed it with animation, but yet he seemed to attach to the new and—as they appeared to me—highly important facts an interest that was academic rather than practical. Of course, his calmness might be assumed; but this did not seem likely, for John Thorndyke was far too sincere and dignified a character to cultivate in private life the artifices of the actor. To strangers, indeed, he presented habitually a calm and impassive exterior; but this was natural to him, and was but the outward sign of his even and judicial habit of mind.
No; there was no doubt that my startling news had left him unmoved, and this must be for one of two reasons: either he already knew all that I had told him (which was perfectly possible), or he had some other and better means of explaining the crime. I was turning over these two alternatives, not unobserved by my watchful colleague, when Polton entered the room; a broad grin was on his face, and a drawing-board, that he carried like a tray, bore twenty-four neatly turned boxwood pieces.
Thorndyke at once entered into the unspoken jest that beamed from the countenance of his subordinate.
"Here is Polton with a problem for you, Jervis," he said. "He assumes that I have invented a new parlour game, and has been trying to work out the moves. Have you succeeded yet, Polton?"
"No, sir, I haven't; but I suspect that one of the players will be a man in a wig and gown."
"Perhaps you are right," said Thorndyke; "but that doesn't take you very far. Let us hear what Dr. Jervis has to say."
"I can make nothing of them," I answered. "Polton showed me the drawing this morning, and then was terrified lest he had committed a breach of confidence, and I have been trying ever since, without a glimmer of success, to guess what they can be for."
"H'm," grunted Thorndyke, as he sauntered up and down the room, teacup in hand, "to guess, eh? I like not that word 'guess' in the mouth of a man of science. What do you mean by a 'guess'?"
His manner was wholly facetious, but I professed to take his question seriously, and replied—
"By a guess, I mean a conclusion arrived at without data."
"Impossible!" he exclaimed, with mock sternness. "Nobody but an utter fool arrives at a conclusion without data."
"Then I must revise my definition instantly," I rejoined. "Let us say that a guess is a conclusion drawn from insufficient facts."
"That is better," said he; "but perhaps it would be better still to say that a guess is a particular and definite conclusion deduced from facts which properly yield only a general and indefinite one. Let us take an instance," he continued. "Looking out of the window, I see a man walking round Paper Buildings. Now suppose I say, after the fashion of the inspired detective of the romances, 'That man is a stationmaster or inspector,' that would be a guess. The observed facts do not yield the conclusion, though they do warrant a conclusion less definite and more general."
"You'd have been right though, sir!" exclaimed Polton, who had stepped forward with me to examine the unconscious subject of the demonstration. "That gent used to be the stationmaster at Camberwell. I remember him well."
The little man was evidently greatly impressed.
"I happen to be right, you see," said Thorndyke; "but I might as easily have been wrong."
"You weren't though, sir," said Polton. "You spotted him at a glance."
In his admiration of the result he cared not a fig for the correctness of the means by which it had been attained.
"Now why do I suggest that he is a stationmaster?" pursued Thorndyke, disregarding his assistant's comment.
"I suppose you were looking at his feet," I answered. "I seem to have noticed that peculiar, splay-footed gait in stationmasters, now that you mention it."
"Quite so. The arch of the foot has given way; the plantar ligaments have become stretched and the deep calf muscles weakened. Then, since bending of the weakened arch causes discomfort, the feet have become turned outwards, by which the bending of the foot is reduced to a minimum; and as the left foot is the more flattened, so it is turned out more than the right. Then the turning out of the toes causes the legs to splay outward from the knees downwards—a very conspicuous condition in a tall man like this one—and you notice that the left leg splays out more than the other.
"But we know that depression of the arch of the foot is brought about by standing for long periods. Continuous pressure on a living structure weakens it, while intermittent pressure strengthens it; so the man who stands on his feet continuously develops a flat instep and a weak calf, while the professional dancer or runner acquires a high instep and a strong calf. Now there are many occupations which involve prolonged standing and so induce the condition of flat foot: waiters, hall-porters, hawkers, policemen, shop-walkers, salesmen, and station officials are examples. But the waiter's gait is characteristic—a quick, shuffling walk which enables him to carry liquids without spilling them. This man walks with a long, swinging stride; he is obviously not a waiter. His dress and appearance in general exclude the idea of a hawker or even a hall-porter; he is a man of poor physique and so cannot be a policeman. The shop-walker or salesman is accustomed to move in relatively confined spaces, and so acquires a short, brisk step, and his dress tends to rather exuberant smartness; the station official patrols long platforms, often at a rapid pace, and so tends to take long strides, while his dress is dignified and neat rather than florid. The last-mentioned characteristics, you see, appear in the subject of our analysis; he agrees with the general description of a stationmaster. But if we therefore conclude that he is a stationmaster, we fall into the time-honoured fallacy of the undistributed middle term—the fallacy that haunts all brilliant guessers, including the detective, not only of romance, but too often also of real life. All that the observed facts justify us in inferring