"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."