“But I thought you said we were to catch him red-handed? Pretty good fools we should have looked if we had found that it was some guest who’d mistaken his room, or somebody who was wanting to borrow a pipe-cleaner!”
“I admit it. But then, you see, I had an intuition, almost amounting to a certainty, that the visitor who intruded upon your room does not come in through the door.”
“Oh, he doesn’t? Then you mean that Gordon and I were merely sacrificed to your peculiar sense of humour—we weren’t really doing any good? My word, Carmichael——”
“You are always too hasty in leaping to conclusions. You were doing a great deal of good by sitting up in the room opposite. You were convincing the mysterious gentleman that I expected him to come through the door. And it was that conviction which emboldened him to pay you a visit last night. I am sorry to have practised any deception on you two, but really it was the only means that occurred to me for inducing the gentleman behind the scenes to act as he did. And after all, I only made you sit up for an hour.”
“An hour,” said Gordon, “cannot be properly measured by the movements of a clock, an inanimate thing which registers time but doesn’t feel it. Many things lengthen time; but three things above all, darkness, silence, and not smoking. The watch we kept last night was a fair equivalent for three hours over a fire with a pipe.”
“Well, I apologize. But you will be glad to hear that the experiment succeeded. Somebody did come into your room last night, Reeves, and wandered all over it, though of course he found nothing that was of the slightest interest to him, because there was nothing to find.”
“And how do you know all this?”
“That is where the chewing-gum comes in. Seccotine would have done: but chewing-gum is more certain. I do not profess to understand why people chew: my impression is that it is merely a kind of fidgeting. Those people who talk about the unconscious would probably tell you that all fidgeting is a form of ‘compensation.’ Observe that word, for it is the great hole in their logic. Their idea is that So-and-so does not murder his grandmother, but he does twiddle his thumbs. They will tell you, consequently, that twiddling your thumbs is a kind of compensation for not murdering your grandmother. But the whole strength of their case should rest on their ability to prove a connexion between the two things, and instead of proving it you will find that they steadily assume it. However, as I was saying—the peculiarity of van Beuren’s special chewing-gum is this: that it can be drawn out to an almost indefinite length, and forms a thread of almost invisible fineness. If you stretch such threads, say, between one chair and another all over a room, as I did round your room, Reeves, last night, the great probability is that a casual visitor will walk into it and carry whole strands of it away with him, without noticing anything peculiar.”
“What!” said Reeves, “you mean like Sherlock Holmes and the cigarette-ash on the carpet?”
“It was not one of Holmes’ more original performances. He had been anticipated, in point of fact, by the prophet Daniel. You should read the story of Bel and the Dragon, Reeves.”