“Did you find nothing in the room which could furnish a clue to the murderer?” he asked.

“Nothing. Stangerson had Drebber’s purse in his pocket, but it seems that this was usual, as he did all the paying. There was eighty odd pounds in it, but nothing had been taken. Whatever the motives of these extraordinary crimes, robbery is certainly not one of them. There were no papers or memoranda in the murdered man’s pocket, except a single telegram, dated from Cleveland about a month ago, and containing the words, ‘J. H. is in Europe.’ There was no name appended to this message.”

“And there was nothing else?” Holmes asked.

“Nothing of any importance. The man’s novel, with which he had read himself to sleep was lying upon the bed, and his pipe was on a chair beside him. There was a glass of water on the table, and on the window-sill a small chip ointment box containing a couple of pills.”

Sherlock Holmes sprang from his chair with an exclamation of delight.

“The last link,” he cried, exultantly. “My case is complete.”

The two detectives stared at him in amazement.

“I have now in my hands,” my companion said, confidently, “all the threads which have formed such a tangle. There are, of course, details to be filled in, but I am as certain of all the main facts, from the time that Drebber parted from Stangerson at the station, up to the discovery of the body of the latter, as if I had seen them with my own eyes. I will give you a proof of my knowledge. Could you lay your hand upon those pills?”

“I have them,” said Lestrade, producing a small white box; “I took them and the purse and the telegram, intending to have them put in a place of safety at the Police Station. It was the merest chance my taking these pills, for I am bound to say that I do not attach any importance to them.”

“Give them here,” said Holmes. “Now, Doctor,” turning to me, “are those ordinary pills?”

They certainly were not. They were of a pearly grey colour, small, round, and almost transparent against the light. “From their lightness and transparency, I should imagine that they are soluble in water,” I remarked.

“Precisely so,” answered Holmes. “Now would you mind going down and fetching that poor little devil of a terrier which has been bad so long, and which the landlady wanted you to put out of its pain yesterday.”

I went downstairs and carried the dog upstairs in my arms. Its laboured breathing and glazing eye showed that it was not far from its end. Indeed, its snow-white muzzle proclaimed that it had already exceeded the usual term of canine existence. I placed it upon a cushion on the rug.