Our morning’s exertions had been too much for my weak health, and I was tired out in the afternoon. After Holmes’ departure for the concert, I lay down upon the sofa and endeavoured to get a couple of hours’ sleep. It was a useless attempt. My mind had been too much excited by all that had occurred, and the strangest fancies and surmises crowded into it. Every time that I closed my eyes I saw before me the distorted baboon-like countenance of the murdered man. So sinister was the impression which that face had produced upon me that I found it difficult to feel anything but gratitude for him who had removed its owner from the world. If ever human features bespoke vice of the most malignant type, they were certainly those of Enoch J. Drebber, of Cleveland. Still I recognized that justice must be done, and that the depravity of the victim was no condonement in the eyes of the law.

The more I thought of it the more extraordinary did my companion’s hypothesis, that the man had been poisoned, appear. I remembered how he had sniffed his lips, and had no doubt that he had detected something which had given rise to the idea. Then, again, if not poison, what had caused the man’s death, since there was neither wound nor marks of strangulation? But, on the other hand, whose blood was that which lay so thickly upon the floor? There were no signs of a struggle, nor had the victim any weapon with which he might have wounded an antagonist. As long as all these questions were unsolved, I felt that sleep would be no easy matter, either for Holmes or myself. His quiet self-confident manner convinced me that he had already formed a theory which explained all the facts, though what it was I could not for an instant conjecture.

He was very late in returning—so late, that I knew that the concert could not have detained him all the time. Dinner was on the table before he appeared.

“It was magnificent,” he said, as he took his seat. “Do you remember what Darwin says about music? He claims that the power of producing and appreciating it existed among the human race long before the power of speech was arrived at. Perhaps that is why we are so subtly influenced by it. There are vague memories in our souls of those misty centuries when the world was in its childhood.”

“That’s rather a broad idea,” I remarked.

“One’s ideas must be as broad as Nature if they are to interpret Nature,” he answered. “What’s the matter? You’re not looking quite yourself. This Brixton Road affair has upset you.”

“To tell the truth, it has,” I said. “I ought to be more case-hardened after my Afghan experiences. I saw my own comrades hacked to pieces at Maiwand without losing my nerve.”

“I can understand. There is a mystery about this which stimulates the imagination; where there is no imagination there is no horror. Have you seen the evening paper?”