Greg said to Nina: "Wait here till I come back or send for you."

"Boss, let me in on this," begged Frank.

"Very well, come with me," said Greg.

They went out via the basement door of the building which led to the side street. The Stickney Arms as has already been described fronted on a narrow roadway which was terraced above the Drive proper. There was a sloping sward between roadway and Drive, which was set out with clumps of ornamental shrubbery. One such clump across the road from the main entrance offered Greg an ideal observation post.

First he took Frank to the two cabs and the waiting men. "This boy is one of us," he said. "Let him wait with you until I give you a signal. Get in the cabs out of sight."

By a roundabout course Greg made his way to his place of concealment. Presently the cab ordered by de Socotra drove up. A moment or two later a little procession appeared in the corridor: de Socotra tenderly supporting Amy on one side, and a trained nurse on the other,—"Where did she come from?" thought Greg. Two hall-boys, laden with rugs, valises, etc., brought up the rear.

As they drew closer, in the nurse Greg suddenly recognized the handsome, hard features of Bianca. "Of course!" he thought. "De Socotra would never trust Amy in an institution without his own personal spy to keep watch of her." Greg smiled in satisfaction. This meant that they were leaving the innocent Se?ora de Socotra alone in the apartment, making his task a hundred times easier. All the luck was not against him to-night.

He let them drive away without making any signal to his men. Since he knew where they were going, there was no especial hurry. The cab turned into the drive and headed down-town. Greg joined his expectant men and issued his instructions.

"Frank, you go back to Nina and tell her they're all gone out except the old lady. She must be pretty near distracted by what's happened. She'll be glad enough to have Nina back for company. Tell Nina to go right up-stairs on the pretext of getting her things. Tell her I'm sending in one of my men who will claim to be the piano man, and that she is to let him in and help him. By the way, what is the name of the people who own that apartment?"

"Merriweather."

"Good. Blossom will say that Mr. Merriweather made an arrangement to have the piano inspected monthly. And he can explain the lateness of his call by saying—let me see—I have it! Blossom will say that his baby is going to be christened to-morrow, and he's doubling up his work to-day, so that he can get a day off. Nothing like a little touch of homeliness to make a story carry!"

"I get you," said Frank.

"Blossom, you heard? The little black book was dropped in the top of the piano, and fell down behind the sounding-board. Your job is to recover it. Work quickly, because de Socotra may not be away long. When you get it you're to hustle home, and tell Bessie to put it in a safe place. Oh yes, and take the girl Nina down there with you, and give her in Bessie's care."

"Will Pa wait for me?" asked Blossom.

"No, take the subway home. I need both cabs. Go on with you. Frank will show you the ropes."

Blossom and Frank made their way towards the basement entrance.

To the remaining two Greg went on: "De Socotra has gone to 411 West Eighty-third Street. Pa, you're job is to trail him as before. You're to come west through Eighty-third, and stop a little way beyond 411. Very likely his cab will be waiting for him. You're to follow him wherever he goes and report by telephone through the drug-store at nine o'clock. I'll arrange with the druggist to keep open late. Hickey, you take me through Eighty-third traveling east."

Eighty-third Street east of Amsterdam proved to be a block of medium-sized private dwellings as much alike as peas in an interminable pod; solemn-faced houses, immaculately cared for, and of the utmost respectability. It was a block, Greg guessed, that would be as silent and undisturbed as a desert after midnight. Number 411 on the north side of the street differed in no respect from its neighbors on either hand. There was not even a doctor's sign in the window. As Greg had expected, de Socotra's cab was waiting below the door.

Greg had Hickey continue to Columbus Avenue and stop in front of a drug-store. Pa Simmons passed them bound in the other direction, and drew up a little beyond de Socotra's cab. Leaving Hickey on watch, Greg went into the drug-store to fish for a little information.

He said to the clerk: "I'm looking for Dr. Tasker's Sanitarium, but I've forgotten the number."

"Four eleven, sir. You can see it from the side door."

"Do you know anything about the place?" Greg pursued, "I mean what sort of a reputation it bears?"

"The very best!" was the impressive reply. The clerk was a young man without humor. "They never have any trouble there. Why, it's run so quiet, so discreet, half the people in the block don't know we have a private asylum—I mean a psychopathic sanitarium in our street. They put the mild cases in the front rooms so they don't have to bar the windows. The back windows is barred all right. The nurses are real ladies and gentlemen; no rough work there. Have you got a case for them?"

"I'm afraid so," said Greg, sighing heavily.

"Well, it's a great misfortune—but you couldn't do better. You might mention I recommended them if you don't mind. One good turn deserves another. I'm anxious to get more of their business. Heavy users of bromides, you understand."

"Bromides!" the word rang ominously on Greg's hearing. Otherwise dope. Strait-jackets had evidently given way to more efficient methods.

"It's a very exclusive place," the clerk went on. "Steep. They say the board is fifty dollars a week, and up."

Greg shook his head sadly. "That's terrible! However, I'll enquire," he said.

Greg bought some cigars, while the clerk continued his gossip, but Greg learned no more to his purpose. Finally he saw Hickey making unostentatious signals, and went outside. Hickey reported that de Socotra had come out of 411 and had driven west. Pa Simmons had gone after him.

"We must kill time for awhile," Greg said. "It would look too miraculous if we turned up one minute after de Socotra had left."

"Well, we'll need gasoline before the night's out," Hickey suggested.

"All right. Find the nearest garage, and fill her up."

A quarter of an hour later Greg was ringing the bell of 411. His heart was beating fast. He had no idea of what he was going to do when he got inside, but left it to circumstances to dictate.

The door was opened by a neat colored maid who suggested a well run private house rather than an institution. At first sight she gave a tone to the place. She was smiling and respectful, yet there was a guarded look in her eyes which suggested that they were accustomed to sights that she kept to herself. Greg asked for Doctor Tasker.

"Doctor Tasker doesn't live here," she said. "He only has his visiting hours. Doctor Emslie is the resident."

"I would like to see him," said Greg.

As he stepped into the house, he observed that an arch had been cut through the party wall into the house on the left, thus throwing the two houses into one. He was shown into a rather luxurious office at the back in which a blonde, bearded man was working at a desk. However, the eagerness with which he looked up suggested that he was not very closely absorbed in his work.

He was a handsome man, yet Greg instinctively disliked him. He was too fat, too red-lipped, too anxious to please. Greg's involuntary verdict was: "Too soft to go out and work up a practice for himself, so he takes an easy thing like th............