"But — ah," observed the bishop, "I — that is, I am bound to remark that this fresh approach would seem to make the matter quite as complicated and incomprehensible as it was before."
"Eh? No. No, I don't agree. Give me this reversal of roles," urged Dr. Fell, with a persuasive air, "and I undertake to simplify it. Heh. Yes."
"I can understand," pursued the other, "how Depping's appearance could have deceived Storer with only one candle burning. The very clothes alone would have had the effect of distracting his eye much as a conjuror does; which is — ah — the first principle of disguise, and, I am told, the only really effective one." It was a struggle for the bishop to include that "I am told"; but he did it. He brooded. "I can even understand the change of voice, allied to the American accent… But there is a more difficult imposture to account for. How do you account for the voice of the man in this room, imitating Depping's? Surely Storer would have known it was not the same?"
The doctor chuckled, and spilled ashes down his waistcoat.
"He would," the doctor agreed, "if he had heard it anywhere else but through a speaking tube." He pointed to the wall. "Of all the ghostly and disembodied effects in the way of communication, commend me to the speaking tube. You yourself would sound like a spirit-voice. Have you never used one? — It isn't like a telephone, you know. Go downstairs, and let each of us speak to you in turn; and I will defy you to identify your own son.
"And, you see, it was only over the speaking tube that the bogus Depping spoke to Storer. The Visitor' went upstairs, entered this room, and the door closed. Afterwards, of course, the real Depping spoke, and there was no deception to puzzle our observant valet."
"For the present," said the bishop, "let's accept the hypothesis… I must insist that we still have as inexplicable a situation as before. Why should Depping and X have put up this imposture between them?"
"I don't think they did."
The bishop remained calm. He said: "Most extraordinary, doctor. I was under the impression that you said-"
"I do not think they put it up between them, confound it," snorted Dr. Fell. "Remember, if you please, that we have only got a reversal of roles. It doesn't alter any of the circumstances. If you say there was collusion between those two, you must explain the same riddles as before. The queer behavior of the man in this room isn't greatly altered because his name is X instead of Depping. Why, if X is working with Depping from the beginning of a carefully conceived plan, does he want the rubber gloves? If Depping brought a disguised X through the front door instead of smuggling him up the balcony, why didn't X do the same for a disguised Depping?… Be calm, my dear sir; I know you yourself pointed out those difficulties. So let's begin with the dinner. Depping didn't eat it, but X did. Whispering to the inner ear, echoing through the halls of consciousness," said Dr. Fell with relish, "comes the sinister question: Why didn't Depping eat his dinner?"