CHAPTER XXII. WHERE THE TIDE TURNED.

Nick Carter did not attempt to stop the fleeing crooks. He saw that the avenue was unobstructed, that the motor car already was attaining high speed, that a shot from his revolver would probably be wasted, and that pursuit was utterly out of the question. He turned back and hastened to rejoin Chick--just as Jack Dorson returned from the ballroom, bringing a glass of water.

Chick was the first to see him, and, having at once suspected him of aiding the crooks, he impulsively started to call him down.

“See here!” he exclaimed. “What motive did you have in bringing this woman----”

“A glass of water! Presumably, of course, because Mrs. Thurlow wanted it. She must have felt ill, for she appears to have fainted.”

Carter had cut in quickly with the interruption, but with a blandness that at once told Chick that he did not want his suspicions revealed to Dorson, and he immediately permitted his chief to take the ribbons.

The entire episode had transpired in far less time than is required to describe it. Scarce three minutes had passed since Professor Karl Graff, most skillfully disguised, an art in which his proficiency soon will become obvious, had seen the opportunity for which he had been waiting.

Mrs. Thurlow was beginning to recover, nevertheless, though still too dazed to realize what had occurred. But the stimulant or counteracting agent held to her nostrils by Tim Hurst, even while he robbed her of her pearls, was rapidly reviving her--as rapidly as in the case of the girl on a cot in the Osgood Hospital.

Nick had glanced in Dorson’s direction when interrupting his assistant, and in the light shed through the French window he caught sight of something glistening back of Mrs. Thurlow’s chair. He picked it up and slipped it into his pocket--the vial accidentally dropped by Tim Hurst in his hasty departure.

Though the stir had been noticed by a few of the persons on the balcony, none supposed that a robbery had been committed, and none had approached to aid or interfere.

Jack Dorson saw at a glance that the rope of pearls was gone, however, and, with nerves now as tense as bowstrings, he quickly took advantage of the detective’s remarks, not for a moment dreaming that they had been designedly made.

“Yes, yes, she said she felt faint,” he replied, holding the glass of water to his aunt’s lips. “I noticed in the ballroom that she was quite pale. I had picked up her handkerchief, or one I supposed was hers.”

“I happened to see you,” Carter nodded. “Wasn’t it hers?”

“She said not.”

“It appears to be missing.”

“She must have dropped it again.”

“Very likely.”

“I told her she had better come out in the air,” Dorson was explaining very glibly, each moment feeling more sure of successfully hiding his guilt. “I came with her and placed her in this chair, and she then asked me to bring her some water.”

“Exactly.” Carter agreed with him readily. “I saw you returning hurriedly, and I thought there might be something wrong. That’s why I came out here.”

“Good heavens!” Dorson now exclaimed, as if suddenly alarmed. “There is something wrong. See? Her rope of pearls is gone. She was wearing it when I left her.”

“It may have unclasped and fallen to the floor,” the detective said quickly. “Look around. Try to find it.”

Dorson obeyed with alacrity, thinking it the most consistent course for one anxious to appear entirely innocent, and Chick hastened to assist him in the search, now seeing plainly that his chief had some covert object in the negative steps he was taking.

Carter had seen, just as the theft of the pearls was mentioned, that Mrs. Thurlow was sufficiently recovered to appreciate the loss and also the mystifying situation. She had started up in her chair, and was feeling with frantic haste for the stolen treasure, when Carter bent nearer and grasped her arm, unobserved by the others.

“Collect yourself and listen,” he whispered impressively. “I am Nick Carter, disguised. The pearls are gone, but that is part of the game I am playing. They will be returned to you to-morrow. Say not a word about me, not even to your nephew. I will return the pearls to you to-morrow evening.”

“But----”

“Don’t oppose me,” Carter forcibly insisted. “Do only what I direct. All depends upon it. Tell Edna not to mention me in the hearing of others. Pretend, now, that you have been robbed and that I am a stranger.”

The scene that immediately followed, for Mrs. Thurlow understood and yielded to him, was about what he expected, and also what he wanted. Amid the ensuing stir and confusion, for an excited throng gathered as soon as the robbery was announced, he informed Dorson that he would go and notify the police, and in company with Chick he immediately departed.

Not until they were on their way down the avenue, however, did Chick make any comments or ask any questions. He then began with saying a bit disgustedly:

“We seem to be playing a losing game. Is that the size of it, chief, or what have you up your sleeve?”

“The crooks have the rope of pearls,” Carter replied, with grim dryness. “There is no denying that.”

“And we are beaten to a frazzle.”

“Oh, no, not quite as bad as that,” the detective quickly protested. “We are not done brown, Chick, by any means.”

“What do you mean? Do you suspect Dorson?”

“Yes, certainly. It was he who made the crime possible. He was coöperating with the rascals who did the more hazardous work.”

“That’s what I suspected.”

“It’s as plain as twice two, Chick, in view of what we know about the girls found unconscious in the hospital grounds. The handkerchief used by Dorson was impregnated with the same mysterious substance with which the girls were temporarily overcome. Obviously, too, the crook who got the pearls administered the antidote or Mrs. Thurlow would not have revived so quickly.”

“The same antidote that restored the four girls.”

“Undoubtedly. Those were experimental cases, Chick, as sure as I’m a foot high, in anticipation of this job. Doctor Devoll was trying out his narcotic, so to speak.”

“You still think he is the chief culprit, the man behind the gun?”

“He was in every instance the man who revived the girls, the physician who appeared to perfectly understand each case.”

“That’s true,” Chick nodded. “I see the point. But why did you conceal your suspicions from Dorson?”

“Because nothing could be gained by revealing them.”

“That’s true, also. Wouldn’t it be well to shadow him, in case he----”

“Not at present,” Carter interrupted. “He will make no immediate move. All that he said was, plainly enough, designed to avert suspicion from himself, and he will continue to conduct himself along the same line for a time. We may get him later.”

“But what are your plans? Where are you going?” Chick impatiently questioned. “Great Scott! we must get on the track of those pearls.”

“I’m on their track, all right,” his chief said grimly. “More surely on their track than at any stage of the game. I told Mrs. Thurlow that I would return them to her to-morrow evening.”

“Is that so?” Chick gazed at him, surprised. “Wasn’t that a rather chesty prediction?”

“Quite so, Chick, but, having got the worst of it, I had to keep her quiet till I could get the best of it.”

“There’s something in that.”

“Besides, I expect to have recovered them by that time.”

“Why so? I thought you had something up your sleeve.”

“It is in my pocket,” Carter corrected dryly.

He took it out; the vial he had picked up unobserved by others. Displaying it between his thumb and fingers, he told Chick where he had found it; then added pointedly:

“It will help some.”

“You mean----”

“I mean that I now intend to corner Doctor David Devoll,” Carter interrupted. “It now is ten o’clock. Before this time to-morrow, Chick, I’ll have Devoll where the wool is short. Take my word for it.”