He took out the two ears as he spoke, and laying a board across his knee he examined them minutely, while Lestrade and I, bending forward on each side of him, glanced alternately at these dreadful relics and at the thoughtful, eager face of our companion. Finally he returned them to the box once more and sat for a while in deep meditation.

“You have observed, of course,” said he at last, “that the ears are not a pair.”

“Yes, I have noticed that. But if this were the practical joke of some students from the dissecting-rooms, it would be as easy for them to send two odd ears as a pair.”

“Precisely. But this is not a practical joke.”

“You are sure of it?”