“That is final,” said Lestrade.
“Yes, that is final,” I involuntarily echoed.
“It is final,” said Holmes.
Something in his tone caught my ear, and I turned to look at him. An extraordinary change had come over his face. It was writhing with inward merriment. His two eyes were shining like stars. It seemed to me that he was making desperate efforts to restrain a convulsive attack of laughter.
“Dear me! Dear me!” he said at last. “Well, now, who would have thought it? And how deceptive appearances may be, to be sure! Such a nice young man to look at! It is a lesson to us not to trust our own judgment, is it not, Lestrade?”
“Yes, some of us are a little too much inclined to be cock-sure, Mr. Holmes,” said Lestrade. The man’s insolence was maddening, but we could not resent it.
“What a providential thing that this young man should press his right thumb against the wall in taking his hat from the peg! Such a very natural action, too, if you come to think of it.” Holmes was outwardly calm, but his whole body gave a wriggle of suppressed excitement as he spoke.
“By the way, Lestrade, who made this remarkable discovery?”
“It was the housekeeper, Mrs. Lexington, who drew the night constable’s attention to it.”
“Where was the night constable?”
“He remained on guard in the bedroom where the crime was committed, so as to see that nothing was touched.”
“But why didn’t the police see this mark yesterday?”