"Thus, you see, there are two ways by which my object may become known, a serious matter if unguarded against. As, however, I recognize the possibilities in advance, there will be no difficulty whatever, and the knowledge will be of no value to any detective, even though he be your Mr. Barnes."
"How will you avoid that danger?"
"My dear boy, do you suppose for an instant that I would reply to that, after pointing out that a detective may be listening? However, I will give you an idea. I will show you what I meant when I said that Pettingill had blundered. You said that he had lost only a button, and thought it clever in Barnes to trace him from the button. But a button may be a most important thing. If I should lose one of the buttons of my vest, whilst committing a crime, Mr. Barnes would trace me out in much less than ten days, and for this reason, they are the only ones of the kind in the world."
"How does that happen? I supposed that buttons were made by the thousand?"
"Not all buttons. For reasons which I need not tell the possibly listening detective, a friend travelling abroad had a set made especially, and brought them back to me as a present. They are six handsomely cut cameos, half the set having the profile head of Juliet, and the others a similar face of Romeo."
"A romance?"
"That is immaterial. Suppose that I should plan a robbery in order to decide this wager. As necessity would not urge me either as to time or place, I should choose my opportunity, let us say when but one person guarded the treasure. That one I should chloroform and also tie. Next, I should help myself to the designated plunder. Suppose that as I were about to depart a sleeping, uncalculated-for pet dog should jump out and bark furiously? I reach for it and it snaps at me, biting my hand. I grapple it by the throat and strangle it, but in its death throes it bites my vest, and a button falls to the ground and rolls away. The dog is at last silenced. Your ordinary burglar by this time would be so unnerved that he would hasten off, not even realizing that he had been bitten, that blood had flowed, or that the button was lost. Mr. Barnes is sent to the house the next day. The lady suspects her coachman, and Mr. Barnes consents to his arrest, not because he thinks him guilty, but because, as the mistress thinks so, he may be, and then more especially, his arrest will lull the fear of the real culprit. Mr. Barnes would observe blood on the ground, on the dog's mouth, and he would find the button. From the button he would find Mr. Thief, with his hand bitten, and there you are."
"But how should you avoid all that?"
"In the first place, were I really wise, I should not have tell-tale buttons about me at such a time. But let us suppose that the time had not been of my own choosing, then the buttons might have been with me. Assured as I should have been that the only person in the house lay chloroformed and tied, I should not have lost my nerve as did the other individual. Neither should I have allowed myself to be bitten, though if the accident had occurred I should have stopped to wash up the stain from the carpet while fresh, and also from the dog's mouth. I should have discovered the loss of the button, searched for and recovered it, untied the victim, and opened the windows, that the odor of chloroform could pass off during the night. In fact, in the morning the only evidence of crime would have been the strangled dog and the absence of the pelf."
"It is easy enough to explain your actions under suppostitious circumstances. But I doubt if in Pettingill's shoes you would have been able to retain your presence of mind, and recover the lost button which led to his final arrest."