Watson had taken a step forward when the bedroom door opened, and the long, thin form of Holmes emerged, his face pale and drawn, but his step and bearing as active as ever. With a single spring he was at the window, and had drawn the blind once more.
"That will do, Billy," said he. "You were in danger of your life then, my boy, and I can't do without you just yet. Well, Watson, it is good to see you in your old quarters once again. You come at a critical moment."
"So I gather."
"You can go, Billy. That boy is a problem, Watson. How far am I justified in allowing him to be in danger?"
"Danger of what, Holmes?"
"Of sudden death. I'm expecting something this evening."
"Expecting what?"
"To be murdered, Watson."
"No, no; you are joking, Holmes!"
"Even my limited sense of humour could evolve a better joke than that. But we may be comfortable in the meantime, may we not? Is alcohol permitted? The gasogene and cigars are in the old place. Let me see you once more in the customary arm-chair. You have not, I hope, learned to despise my pipe and my lamentable tobacco? It has to take the place of food these days."
"But why not eat?"
"Because the faculties become refined when you starve them. Why, surely, as a doctor, my dear Watson, you must admit that what your digestion gains in the way of blood supply is so much lost to the brain. I am a brain, Watson. The rest of me is a mere appendix. Therefore, it is the brain I must consider."