"But surely the letters are connected with our case, and who else could it be?"
Since the finding of the glove and the testimony of the three gamins Emily was coming around to Shagarach's view of Harry Arnold's possible guilt and the attack on Robert's lawyer had aroused her sympathies so as almost if not quite to convince her.
"Mr. McCausland is very keen—a wonderful man—of deceptive exterior, but like the rest of us, he sometimes makes mistakes," said Shagarach. "His defect is that he uses the logical method only and ignores the psychological. It is necessary first to find out if the accused is capable of the crime. I first became sure of Robert Floyd's innocence when I saw him through the cell-bars of the jail. He is incapable of the crime."
"My son so admires your lover," added Mrs. Shagarach.
"These other friends of mine," continued her son, taking down the thumbed volume which he had put back when the tapping startled them, "commit the opposite error. They are strictly physiological. They predict too much from a man's physical peculiarities."
The book he opened for Emily was a treatment on criminology, illustrated with villainous heads in profile and full face. It was in Italian, so Shagarach exchanged it for another.
"Behold the brands of the true criminal—'enormous zygomae,' 'ear lobes attached to the cheek,' 'spatulate fingernails——'"
"That takes in Mr. McCausland," said Emily, roguishly. She had got over her fright by this time and the allusion to spatulate fingernails recalled the whole train of events which had ended in the inspector's discomfiture.
"The refutation of such theorists," said Shagarach, "is simple. We need only point to the fact that the greatest crimes are committed by men who are not professional criminals at all and who do not belong to the criminal type."
"Like this man," said the mother, going to a closet at one side and drawing forth a bundle of photographs. One of them she showed to Emily. It was Harry Arnold, bold and handsome, with the shaggy cape coat thrown carelessly over his shoulders.