"What tainted people you have to deal with!" she exclaimed, unconsciously continuing her vein of silent thought. "I should crave another environment, I think."

"Your Christ lived with sinners and publicans. And they are not all tainted, my dear," added the mother, smiling so that Emily might know whom she meant to except. "There is so much in common between my son and Mr. Floyd. Both proud, serious, too serious, I tell him, and both true Castilians in honor. But the one looked about wisely and found him a—lady; and the other—"

"The other will grow gray by his good mother's side, I fear," said Shagarach, gently kissing the laughing and delighted old lady. Emily smiled herself to see John Davidson's sphinx, whose reticence outside was indeed a mask of stone, unbending thus to the frankness and simplicity of a child. The mother's ways were more demonstrative, but with deep reserves of dignity.

"But you are right, Miss Barlow. The lawyer's profession is one shade more distasteful than the surgeon's, for he handles the moral sores of humanity."

"Handles them to cure them," cried Emily, shifting about, like a true woman.

"Possibly. Though for my own part I agree with those who hold that the law perpetrates no less wickedness than it punishes—were it not that it prevents more than it perpetrates," he added, smiling, "we should live in a very troublesome world. It is a profession which uses the conscience as a whetstone upon which to sharpen the intellect. I attribute the venality of our congress and legislatures partly to the disproportion among them of lawyers."

"But surely there are exceptions?"

"In the criminal courts," answered Shagarach. Emily asked herself if this was Shagarach's destiny, to continue as a criminal lawyer. As if in answer to her question, he added:

"There alone one can feel at all times that he is either protecting the innocent or punishing the guilty. This is my working library," he pointed to the thumbed volumes on the shelves. Emily noticed that most of them were treatises on psychology, the old and the new.

"I do not carry the keys for those," said his mother, gayly.

"Light to illuminate our case," Shagarach took down one of the books. "By the way, my correspondent, Mr. Skull-and-Crossbones, has honored me again."

The two ladies started and the mother seized her son by the arm.

"A black-edged letter, apprising me that I am marked and doomed." Just then Emily heard the strange tapping that had startled her before. It came from the window of the front parlor this time. She shuddered in a sudden terror and drew closer to Mrs. Shagarach. The old lady had heard the sound and blanched a little, but her voice was firm when she spoke:

"Is that a mouse in the wainscoting, my son?"

"I thought it was a tapping at the window, mother."

"Go and look. There may be a stranger in the yard."

Shagarach raised the curtain and looked out, then opened the window. The cool night air flowed in and heightened Emily's tremors so that the elder lady took pity on her.

"There is no one in sight, mother, but I will put on my hat and go out the back door."

In a few minutes Shagarach returned by the street entrance.

"I thought I heard footsteps in the passageway and followed them around, but there is no one. The yard is empty."

"I will inform the policeman to-morrow," said his mother. "There are many loiterers about in these bad times. And you should acquaint them with the letter you received."

"I have done so, mother. I have considered it strange," he added, turning toward Emily, "that the parties opposed to us in the Floyd case should resort to murder. It is a confession of guilt."

"If they are caught."

"Murder will out. Moreover, I do not work alone. I have engaged the assistance of—whom do you think?"

"Of Mr. McCausland," said the mother, breaking in. "It was my suggestion."

"McCausland investigating Harry Arnold!" exclaimed Emily.

"Is it not amusing? But he will not allow that Arnold is at all open to suspicion, and of course I have not laid all my evidence before him."

"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.

"Has he enormous zygomae, ear-lobes attached to his cheek?" she asked.

"I wish I could see his fingernails," laughed Emily.

"Arnold's face in repose does not show much capacity for evil. But it lights up badly. I have seen him crossed and in passion."

"I think he looks as if he were veined of evil and good," said Emily frankly, studying the portrait long, as she loved to do. She had seen Harry once when he was at his best. Besides, her service in the photograph studio had made her something of a physiognomist, too, though not, of course, such a soul-reader as Shagarach.

"His crimes are of the preventable order and therefore the more culpable. There are men born to crime, as the theorists argue; others driven to crime. For both of these classes it is hardly more than a misplaced emphasis, a wrong direction of energies."

"Here is another volume—I am showing you all my workshop. Does it fatigue you?"

"Nothing which helps to clear up the mystery is dull to me," answered Emily.

"This treatise deals with 'Incidental Homicide.' Rather legal than clinical. The cases are all parallel to ours. The indictment, by the way, has just been given out. The weakest count charges Robert Floyd with arson and murder in the second degree. The punishment for that is only imprisonment for life."

"Only! Robert says he would rather be hanged."

"Let him have no fear of either," said Mrs. Shagarach, cheerily.

"The newspapers tell us that the government offered much new evidence," said Shagarach.

"I should like to know what it was," cried Emily, eagerly.

"So should I. Ordinarily, the grand-jury room is leaky enough, but Mr. McCausland, who is the government in this case, appears to have found a way to seal it hermetically."

"Perhaps he padlocked the jurors' lips," suggested Emily, whereat all three were merry.

From time to time during the conversation relapses of the old shudder had come back to Emily, though the tapping had utterly ceased since Shagarach investigated the yard. He had left the curtain half-raised, so that any one approaching the window would be visible from within. It was just at this moment that she happened to change her seat, bringing her face around to the darkened window. Before the others could catch her, she had risen, pointed to the window and fallen to the floor with a terrified shriek.

Shagarach started to raise her, but the terrible detonation of a pistol rung out, sacrilegiously invading their quietude. Then all was darkness, a noise of crashing glass telling that the lamp had been shattered and extinguished. Another report followed and another. Mrs. Shagarach, trembling, heard her son quickly crossing to the window. The panes seemed to be broken, and there were sounds of a scuffle, mingled with a gnashing of teeth and growls more animal than human. Suddenly, with a ripping sound, the scuffle ceased, and rapid footsteps were heard pattering away. Then her son spoke to her in the loud, firm voice which he used in all practical affairs.

"Light the little lamp, mother. It is safe now. There are matches on the mantel."

"Are you hurt, Meyer?" she asked, anxiously, while lighting the lamp.

"A little," he answered.

"You were shot, my son?" she cried, embracing him.

"No. Let us revive Miss Barlow. Some water, Rachel," he said to the old servant who had come to the door.

When Emily came to she found Mrs. Shagarach sponging her forehead, while her son was washing his hands in a basin of bloody water.

"Wrap the cotton around them quickly, Rachel," he was saying. "I must notify the police."

"Meyer, it is not safe."

Emily heard the mother protesting, then swooned again. When full consciousness returned the lawyer was gone and the three women were alone in the room. Rachel began picking up the fragments of the lamp. Only its chimney and globe had been broken, the metal being still intact. The windowpanes showed great ragged holes, which explained the laceration of Shagarach's hands.

"Poor lady," cried the mother. "This is ill treatment we give you. But we are not to blame. It is the wicked enemies who are pursuing us all—your lover and my son." With terms of endearment she petted the weak girl back into a coherent understanding of her position. But every now and then the remembrance of something would cause her to shudder again visibly; whereat the elder lady would renew her caresses.

"I have notified the policeman. That was the best I could do," said Shagarach, re-entering. He looked extremely grave. It was a narrow escape for one or more of the three. "This is all I have to identify him by. It was detached in the struggle."

He laid a common coat button down on the table, with a piece of cloth adhering.

"That face! Who could ever forget it?" cried Emily.

"You saw him, then?" asked son and the mother in one breath.

"Shall I call it 'him'? Was it a man?" answered Emily. "Rather a monster, no more than half-human."

"It had the form of a man," said Shagarach, "as I felt it through the glass."

Rachel was busy bandaging his cuts with plaster during this conversation, but they bled through, calling for the surgeon's thread.

"But it snarled like a tiger," said the mother.

"Oh the wild, blue eyes! They were staring at me through the cleft of the draperies. And the demon leer, and the forehead, retreating like a frog's——"

"It is the oaf I passed on the pier," cried Shagarach, interrupting Emily. "We have found Mr. Skull-and-Crossbones."

"Oaf? What is oaf?" asked the mother.

"An idiot, a monster."

She shuddered.

"A man of that description cannot long elude search," said the son in a more hopeful tone.

"They are often very cunning," replied the mother.

"Can it be Harry Arnold would employ such an agent?" asked Emily, still trembling.

"Twice," said Shagarach, as if speaking to himself. "A cap and a button. Men have been captured on slighter clews."

"You will give the button to Mr. McCausland," said the mother.

"Yes; since it fits with the cap."

"Maybe he will help you to bring Harry Arnold to justice."

"And so to acquit Robert Floyd," said Shagarach, smiling to cheer his guest.

The mention of her lover restored the wilted girl, who was brave enough when there was anything definite to be done. Shagarach showed her the book on "Arson" which he had been holding when the first shot was fired. The bullet had pierced it on its career toward the lamp.

"The bullets will be evidence also," he said, "and I will measure the footprints before the rain comes down and washes them away."

"You will wish to go home, poor child," said Mrs. Shagarach to Emily. "Not yet, but soon, when you are stronger. Rachel!"

The soothing words of the mother warmed Emily quite as much as the wine which Rachel brought. Meanwhile two policemen entered and began to examine the premises. Shagarach visited the yard in their company and soon returned with a tape measure and a paper block, on which he had recorded the lengths of the footprints.

He was assiduous in his regrets and inquiries toward Emily and insisted on accompanying her home in a carriage, which the mother, however, would not allow them to enter until she had exacted from her visitor a promise that she would come again on an appointed evening, and pressed upon her in true oriental fashion a certain rose-embroidered gossamer scarf for which Emily had expressed admiration.

At her own door the sweet girl heard Shagarach order the hackman to drive to Dr. Lund's, and she guessed that his cuts would be somewhat worse for the delay in stitching them. That night she saw gorgon faces leering in at her window, and her dreams were of new-moon scimiters and the rocking of the camel ride.