When Richard Duvall left the Hotel Universelle, en route to the office of Dr. Hartmann, he had no definite idea of just what he intended to do on reaching there. One thought was uppermost in his mind—he must prevent, in some way, and at any cost, the delivery of the snuff box to Hartmann, and since to follow Seltz to the latter's office would avail him nothing, he decided to precede him there.

During the drive, he began to formulate a plan, daring in its conception, extremely dangerous in its execution, yet one which, if carried out with courage and determination, promised success. He was perfecting in his mind the details of this plan when the carriage turned into the driveway at Dr. Hartmann's.

So occupied had he become with his thoughts that he failed to observe the figure of Grace, standing behind the maid in the open doorway; she disappeared into the reception-room before he had alighted from the cab. He went up to the servant, assumed an air of dignified assurance, and announced that he wished to see Dr. Hartmann at once.

The maid ushered him in, glanced into the parlor, observed Grace sitting there, apparently reading, and then throwing open the door to the left which gave admittance to the doctor's office, bade Duvall enter. The latter stepped in at once, without looking into the room across the hall. Had he done so, he would have observed his wife, whom he fully supposed to be quietly waiting for him in Paris, rise from her chair with a frightened face and start impulsively toward him.

For a moment Grace was on the point of calling out—she wanted to let Richard know that she was there. She wanted to see him—to talk to him, to realize the happiness of being once again in his presence. It had been, since their parting the day before, her constant thought. Then she suddenly realized that Monsieur Lefevre had warned her not to appear to recognize her husband, should she meet him in the course of her adventures. The thought checked her—she paused at the door of the reception-room and glanced down the hall.

The servant who had admitted Duvall had disappeared toward the rear of the house. Everything about her seemed quiet. She started across the hall, determined to enter the room into which Richard had just vanished, when she heard the sound of rapid footsteps approaching her. With a start she turned and again entered the parlor, assuming a careless manner she by no means felt.

She had scarcely seated herself in the chair by the fire, and opened her book, when she saw Dr. Hartmann appear in the hall and enter the door which led to the outer office.

Grace was undecided as to what she should do next. Her safest course, she ultimately concluded, was to do nothing. She remained quietly in her seat, pretending to read her book, but all the while watching, with anxious eyes, the door on the other side of the hall.

Richard Duvall, meanwhile, had entered the waiting room, his mind fully made up as to the course he was about to pursue. During the few moments which intervened, until the doctor's arrival, he looked keenly about the room, examining it in detail, fixing its entrances and exits firmly in his mind, so as to be prepared for any emergency which might arise.

The room was a large one. Along the side facing the entrance door, as well as that which fronted on the park, were big curtained windows, set in deep recesses, and between them, cases of books. At the far end of the room, toward the rear of the house, was another door. Duvall stole over to it, listened carefully, then slowly opened it and looked within. The room proved to be the doctor's private office, and he saw at once that it was built in a sort of ell, and could not be entered except through the room in which he stood. There was a door, it is true, in the right-hand wall, which had once given entrance to the hall, but against this a heavy instrument case, with glass doors, now stood.

Duvall withdrew his head and shoulders from the doorway, nodding to himself in a satisfied way, then noiselessly closed the door and returned to the center of the room.

In a moment Dr. Hartmann came in, glancing at him sharply. "Good-morning, sir," he remarked, in French. "You wish to see me?"

The detective took a card-case from his pocket and tendered the doctor a card. It was one of many which he carried for such emergencies, and bore the name of Stephen Brooks.

"Yes," he said, pleasantly. "I came to consult you concerning a curious case."

"Indeed!" The doctor looked at the card carelessly. "I see that you are an American." He began to speak in English. "Sit down, please."

"Thank you." Duvall took a chair.

"What is the nature of the case, may I ask?"

"Doctor—I've heard so much of your wonderful cures—of your remarkable success in treating mental disorders, that I have ventured to come to you in the hope that you may be able to help me."

The doctor smiled, not displeased at the other's flattery. "What is the cause of your trouble, Mr. Brooks?"

Duvall observed him thoughtfully for a moment. "If a person has delusions upon one particular subject, is he on that account necessarily insane?"

"Not at all. Manias of various sorts are not uncommon, and generally curable. Why do you ask?"

"Because I want you to treat such a case."

The doctor considered his patient narrowly. "Of course, you understand, Mr. Brooks, that my professional charges are very high."

Duvall took out his pocketbook and removing from it a note for a hundred francs, laid it carelessly on the table. "I have understood so, Doctor," he remarked. "Luckily I am a man of considerable wealth."

"In that event," Hartmann remarked, eying the bill in a gratified way, "I am at your service. What is the nature of your complaint?"

"It isn't about myself that I have come," Duvall hastened to inform him. "It concerns a man in my employ—my valet, to be exact."

"Your valet?" The doctor frowned, and made as though to rise. "My dear sir—"

"One moment, please, Doctor. The man is a most worthy fellow. He has been in my service for years. A Belgian, too, I think. I have a very high regard for him—an excellent servant, except for the peculiar delusions with which he has lately become possessed."

"I fear that I cannot undertake his treatment, Mr. Brooks. I receive only a few patients, and those of the highest standing."

"I know that. I did not propose to have the man quartered here in your house. I merely want you to examine him, in order that I may find out whether his case is curable or not. If it is, I shall take him to Paris and place him under treatment—if not, I must, of course, discharge him. It is for that reason that I have come to you."

"What are the man's symptoms?" asked the doctor, shortly.

"He imagines, from time to time, that he has been robbed."

"That is by no means uncommon. I have seen many such cases. Are these delusions confined to any one subject?"

"No. At times he fancies that money has been taken from him. At other times, jewelry that he has never possessed. Once he accused me of robbing him of a pair of shoes, and demanded that I pay him a large sum of money for them. I have generally succeeded in quieting him by assuring him that the stolen articles would be forthcoming later on."

"Excellent. And how long has this condition been in evidence?"

"About a month, now. During the past week, however, the attacks have been more frequent. Last night he informed me that someone had taken from him a diamond ring—of course he had never owned one—and wanted five thousand francs in return. I assured him that I would get him the money this morning."

"The case does not seem particularly difficult, Mr. Brooks, from what you tell me. Of course I could determine better after a personal examination."

"Exactly. And if you find no other conditions of an alarming nature, you think a cure possible?"

"Undoubtedly. When can I see the man?"

Duvall took out his watch. "I requested him to meet me here to-day at noon," he said. "I did not tell him he was coming for a medical examination. He might have refused to come. I let him think that you might be able to recover the diamond ring he thinks has been stolen from him. I thought it best to humor him. I should have brought him with me, but he had arranged to go this morning to see his people, who live in the town. He was to come directly here, after leaving them." He went over to the window and looked toward the road. "I am surprised that he is so late. Usually he is punctuality itself."

The doctor rose. "No doubt he will be here very soon," he remarked. "You can wait here, if you like. I will join you on his arrival. Meanwhile, as I have some matters to attend to in my office, I beg that you will excuse me." He opened the door at the rear of the room, which led to his private office. "When the man arrives, kindly let me know."

Duvall glanced toward the door through which Dr. Hartmann had just passed, then paused for several moments, listening; then he walked noiselessly across the room, and paused before the study door. Within all was quiet. Stooping down, he applied his eye to the keyhole. Dr. Hartmann sat at a large rosewood desk, busily writing.

With a smile of satisfaction the detective arose, and going to the door which led to the hall, drew from the lock the key which stood in it, and then, opening the door slightly, inserted the key in the lock on the other side of the door. As he did so, he peered out across the hall, and for a moment the key almost dropped from his fingers. There, facing him, sat Grace, his wife, whom he had supposed to be safely in Paris. The sight for a moment completely upset him—he paused, gazing at her with an expression of incredulity.

Grace rose, and came toward her husband, her face pale, her lips parted. "Richard," she whispered softly, then became suddenly silent as he pressed his finger to his lips.

As they stood there thus, facing each other in grave uncertainty, Duvall heard the sound of a vehicle being driven up the graveled road. He glanced toward the glass entrance door and saw a cab approaching the house, in which sat Seltz. He turned to Grace, and spoke in a voice so low as to be scarcely audible.

"Open the door at once—before the man can ring. Pretend to be a maid. Show him in here immediately. Quick." He withdrew into the waiting-room, leaving Grace staring at him in amazement. For a moment she hesitated. It seemed so cruel, to be this near to him, and yet to not even be able to touch his hand! Then she went quickly to the front door and threw it open as Seltz came up the steps.

Richard Duvall, alone in Dr. Hartmann's outer office, had not long to wait. He had hardly succeeded in throwing off the agitation which the unexpected sight of Grace had caused him, when the door from the hall was opened, and Grace admitted Seltz to the room.

The latter glanced at Duvall with a curious look, but said nothing. Grace withdrew, closing the door quietly after her. The detective went up to the newcomer and addressed him in a low tone.

"You are Oscar Seltz, from London?" he asked, bluntly.

The man appeared greatly taken back. "Yes," he said, haltingly. "I wish to see Dr. Hartmann."

"About the snuff box, of course?"

Again the man started. "Who are you?" he asked, suddenly suspicious.

"I am Dr. Hartmann's assistant. He has been waiting for you. You have the box with you, of course?"

The man felt carefully in his pocket, and presently drew out a small object done up in paper. "Yes, I have it. The price was to be twenty-five hundred francs."

"That is correct," remarked the detective. "Give it to me."

Seltz drew back his hand. "I want the money first, and I cannot deliver it to any one but Dr. Hartmann."

"Dr. Hartmann is in the next room," said Duvall, with a pleasant smile. "He has the money all ready for you. I will call him. But first, let me see if you have really secured what we want." He held out his hand. "Don't be afraid," he said. "I shall not leave the room. The box will not be out of your sight."

Seltz appeared to consider the matter for a brief moment, but the detective's manner reassured him. He extended the package toward Duvall. "It is there, all right," he laughed, softly. "And a hard time I had getting it."

Without making any comment, Duvall took the package, quickly tore off the coarse paper wrappings, and saw inside a small round ivory box, its top ornamented with a number of small pearls, arranged in a circular design about its circumference. He glanced swiftly at it, crushed the paper into his pocket, then started toward the door at the rear.

"Where are you going?" demanded Seltz, harshly, his hand going toward his pocket, as though for a weapon.

"To call the doctor, my man," Duvall replied. "Don't excite yourself. He will be here in a moment, with your money." Without a moment's hesitation he crossed to the study door and tapped lightly upon it. As he did so, his back was toward Seltz, hence the latter did not see the swift movement, by which he conveyed the snuff box to the pocket of his waistcoat. When, after a few moments' delay, Dr. Hartmann appeared on the threshold, Duvall's hands were both quite empty.

As the doctor entered the room, the detective gave a quick nod toward Seltz. "My man," he remarked, in a low tone. "He seems to be rather bad, this morning;" then aloud, "Oscar, this is Doctor Hartmann."

Seltz bowed, then stood uncomfortably, shifting his weight from one foot to the other as the doctor bent upon him a searching glance. "Sit down, my good fellow," the latter presently remarked, as he took a chair.

"I—I don't think I had better, sir," he stammered. "I am in somewhat of a hurry—"

The doctor interrupted him, in a soothing voice. "There, there. Sit down. I want to talk to you."

Seltz glanced helplessly toward Duvall, apparently somewhat confused by the reception which Dr. Hartmann had accorded him. It was not entirely what he had expected.

"I have explained everything to the doctor," remarked Duvall hastily. "He understands about the money you requested." He looked significantly at Dr. Hartmann.

"Then I hope the matter can be settled at once," said Seltz, apparently much relieved. He made no movement to sit down, but continued to look expectantly at Dr. Hartmann.

The latter nodded in a grave and reassuring way. "Give yourself no uneasiness, my man. Everything will be satisfactorily arranged. Meanwhile, sit down, if you please, and tell me something about yourself. I understand you have been greatly worried, of late. Not quite yourself—let us say."

Seltz looked at him in blank amazement. "I haven't been worried by anything, except the business which brought me here. I want my money—"

"Exactly—exactly," the doctor assented, in a soothing voice. "You shall have your money in due time. I promise you that. But first sit down and let us have a little chat."

Seltz sat down, helplessly. Apparently he was at a loss as to just what to say next. The doctor had told him that the money he expected would be forthcoming—he resigned himself in patience to await the latter's pleasure. For a moment he glanced at Duvall, however. "You should not have taken it from me," he said, peevishly.

Duvall looked quickly at Dr. Hartmann. The latter at once spoke up. "Give the matter no further thought, my man," he said, gravely. "I will see that you are fairly treated. But before we go ahead, I want you to tell me more about yourself—your life—your amusements—"

"What the devil have my amusements got to do with the matter?" exclaimed Seltz, his voice trembling with anger. "I tell you I want my money."

"And I tell you you shall have it. But, now, I insist that you let the matter drop for the present and answer my questions, otherwise I can do nothing to help you."

The remark quieted Seltz somewhat. He was, after all, in a peculiar position. The snuff box was gone. He cursed his stupidity in having let it pass out of his possession before the price agreed upon for its delivery had been forthcoming. That Dr. Hartmann did not question the payment of the money, however, was reassuring. He determined to answer as well as he could whatever questions the doctor might see fit to ask him.

The latter continued to examine his supposed patient with a shrewdly professional air. "How old are you, my man?" he suddenly inquired.

"Thirty-six."

"Do you drink?"

"Yes—I—I drink occasionally."

"Use any drugs?"

"No."

"Appetite good?"

"Yes."

"Sleep well?"

"Yes—pretty well."

"Have you had any shock, recently. Has anything happened to make you nervous, or excitable?"

Seltz glanced nervously from Duvall to the doctor and back again. What, he wondered, was the purpose of this examination? Was Dr. Hartmann trying to lead him into damaging admissions concerning the method he had employed to secure the snuff box? He scowled, then suddenly spoke. "It's none of your affair, is it? if I have."

"Oscar!" said Duvall, in a tone of remonstrance. "Don't speak to the doctor in that way."

"Oscar!" The man turned on the detective angrily. "Look here—you took that—that—" he hesitated, fearful that some trap had been set for him—"that article away from me—now see that I get my money."

The doctor glanced at Duvall. "He seems to be possessed with the one idea," he remarked, sotto voce, then turned to Seltz again. "My good man, I have already assured you that Mr. Brooks and myself will see that you get your money. What more do you want?"

"I want the money," Seltz cried, losing his patience, "and I want it quick." He sprang from his chair, and his hand shot toward his pocket, whence it reappeared in a moment with a revolver. "No more of this nonsense, now. I want the cash."

The doctor, who had also sprung to his feet, started toward the angry barber with outstretched hands. Seltz whirled on him, the revolver pointed directly at Hartmann's head. "Keep off," he cried. In his excitement he had forgotten Duvall, who at once seized him from behind. "Look out, Doctor," he cried, as he threw his arm about the fellow's neck and slowly throttled him. "He's gone quite insane—dangerous—take away the revolver."

As he spoke, he tightened his arm about Seltz's throat until the latter gasped for breath. The revolver fell from his nerveless grasp—he clutched at the detective's arm and tried to tear it from his throat, all the while groaning and sputtering at a great rate.

"Hopelessly insane, I fear," said the doctor, as he picked up the fallen revolver. "You had best take him away at once."

"But, Doctor, I can't do anything with him in this violent state. Can't you give him something to quiet him?"

"Nothing but a hypodermic. He wouldn't swallow a drug, I fear."

"Then give him a hypodermic at once. I've got to get him away from here, somehow." He tightened his hold on Seltz's throat as the latter struggled furiously, trying his best to get away. Luckily for Duvall, his adversary was a man of only moderate strength, but he struggled like the madman the doctor supposed him to be, trying in vain to speak. The detective's arm, however, tightly wound about his throat, effectually prevented his cries from becoming intelligible.

"I'm so sorry, Doctor," Duvall went on, as Hartmann prepared his hypodermic needle and approaching the struggling man, took hold of one of his arms and bared it with a quick motion. "I wouldn't have subjected you to all this annoyance for anything. The poor fellow has been getting worse for days, but I had no idea, when he left me this morning, that he would be like this."

"It frequently happens," the doctor remarked, as he pressed the syringe into the man's forearm and then withdrew it quickly. "There—he'll soon be all right now. Just hold him there for a few moments longer, Mr. Brooks and he'll be sleeping like a child."

Even as he spoke, the struggles of the man in Duvall's arms became less violent—his efforts to cry out less vigorous. "It's a sad case," the detective remarked. "I am very much afraid that he must be sent to an asylum."

"Undoubtedly the best place for him, my dear sir," remarked Hartmann, dryly. "I see your cab is waiting, outside. As soon as the man is quiet, I will have one of my attendants help you to carry him to it." He went over to Seltz, who was now struggling faintly, and felt his pulse. "He is quite harmless now," he observed, looking keenly into the man's face. "I will call one of my men." He went to the wall and pressed an electric button.

Duvall allowed the limp body of the barber to slip softly into a chair. "Poor Oscar!" he said, musingly, looking down at the huddled-up figure. "What a pity! Such a faithful fellow, too!" He turned to Hartmann. "I feel almost as though I had lost an old friend."

The doctor smiled. "Rather a dangerous one, I should say," he remarked, as he glanced at the revolver on the table. "You will want this, I suppose."

Duvall took the revolver and thrust it into his pocket. "Might as well take it along, I suppose, doctor. Now about my bill—do I owe you anything in addition to the fee I paid you on my arrival?" He felt for his pocketbook.

"Nothing, my dear sir." The doctor smiled. "I feel that in accepting your fee I am robbing you." He drew the note from his pocket, but Duvall waved it aside.

"I insist, my dear sir. You have given me your valuable time, at least, even if you could do this poor fellow no good." He paused, as an attendant in a gray uniform entered the room.

"Max," said the doctor, addressing the man, "help this gentleman put his friend into the cab."

The man came forward, and he and Duvall picked up the limp figure of Seltz, who was now sleeping soundly. In a few moments they had transferred him to the cab outside.

As they left the house, Duvall saw Grace standing near the door, her face pale, her eyes seeking his. He avoided her glances, making no sign that he recognized her. The doctor, somewhat annoyed, requested her, with elaborate but firm politeness, to withdraw. She did so, without looking back, but her heart was beating until it shook her whole body, and she longed to run to her husband and drive off with him, in spite of the doctor's presence. Somehow she felt that the necessity which had kept her a prisoner in this house no longer existed—that Richard had succeeded in recovering the ivory snuff box, and would soon send her word to join him, so that they might return to Paris together. She went to her room, ordered some luncheon brought to her, and sat down to await his message.

Meanwhile, Duvall, with Seltz beside him, drove rapidly away from the house, his arm about the man's unconscious figure. At the gate of the park he saw another cab waiting, and in a moment perceived that it contained Dufrenne, who in accordance with his instructions had been following Seltz. Duvall nodded to him, then pointed silently down the street. Dufrenne at once ordered his driver to follow. In a short time they had reached the Hotel Metropole, and Seltz, with the assistance of two of the porters, had been carried upstairs and placed on the bed. Duvall explained to the manager of the hotel that the man was a friend of his, who had been taken ill, and needed to sleep for a few hours. He also engaged the adjoining room at once, and thither he and Dufrenne presently repaired to examine the snuff box which, until now, had been reposing safely in the detective's waistcoat pocket.

He drew it out, when they were alone, and silently handed it to Dufrenne. The little old Frenchman took one look at it, then threw up his hands with a cry of joy. "It is the Ambassador's snuff box. Heavens be praised!" he cried, as the tears coursed down his withered cheeks.

Richard Duvall looked at the tense figure, the agitated face of his companion, and once again a feeling of surprise swept over him, as he observed the little Frenchman's joy at the recovery of Monsieur de Grissac's snuff box.

Throughout the exciting events of the morning, and of the night before, the detective had lost sight of the apparent insignificance of the object of their search; now that he for the first time saw it before him, his curiosity was once more aroused. Surely there must be something of vast interest about this apparently worthless bit of ivory, to make its theft the reason for a brutal murder, its recovery a matter of such extreme importance that Monsieur Lefevre should consider the honor of his country at stake.

He took the box from Dufrenne's trembling fingers and examined it carefully. It was about two and a half inches in circumference, and quite shallow, not over half an inch in depth, in all. The ivory was old and yellow from use and time, and very thin and smooth. The lightness of the box surprised him—it seemed to weigh almost nothing, as he balanced it on the palm of his hand.

The circular top of the box was curiously ornamented with a circle of small colorless pearls, of trifling value, set at regular intervals about the edge of the cover. Within this row of pearls was an inscription in Latin, carved in tiny letters in the ivory. From its first words, "Pater noster," Duvall saw that it was the Lord's Prayer. The letters extended around the circumference of the box in several concentric lines, or rings, inside of the ring of pearls. In the center of the box was a cross of ivory, carved so as to be slightly raised above its general surface. Beyond this, the box contained no other ornamentation.

Along the front edge of the box Duvall noticed a small spring. He pressed it, in considerable excitement. Evidently the reason for the box's value must be within—some papers, no doubt, of extreme importance. He saw the cover of the box fly upward and glanced hastily inside. The box contained nothing but a few pinches of snuff.

Duvall was almost tempted to laugh. The whole thing seemed so ridiculous—so utterly absurd. Absent-mindedly he tried a pinch of the snuff, inhaling it into his nostrils. It produced nothing more startling than a violent fit of sneezing. Undoubtedly Monsieur de Grissac had told the truth. He did use snuff.

Closing the box, Duvall regarded it for a moment in silence, then looked at Dufrenne. "It isn't worth a hundred francs," he said.

"The box?" answered the curio dealer, as he followed Duvall's glances. "No, monsieur—what you say is indeed true, yet I would not sell it for a hundred million."

"But why? What is there about it that makes it so valuable? Surely you can tell me that, now that we have safely recovered it."

"Alas, monsieur. I could not tell you, even if I knew, which I assure you I do not. I can only say that Monsieur Lefevre has told me that it holds within it the honor of my beloved country, and therefore I would not sell it for all the money in the world."

Duvall was clearly puzzled. "Well," he said at length, as he thrust the box into his pocket, "there's evidently some mystery about the thing that I do not understand, but I suppose I shall, some day. Just at present our first duty is to return the box to Monsieur de Grissac."

"You are right, monsieur, and at once. There is a train for Antwerp in half an hour. From there we can take the night boat to Harwich. Let us set out without further delay."

"And that fellow in there?" remarked the detective with a grim laugh. "We've got to take him with us, you know. He'll be wanted in London for the murder of the man Noël."

"Yes. That also is important." Dufrenne went into the adjoining room and stood looking at the sleeping barber. "But not so important as the return of the snuff box to Monsieur de Grissac."

Duvall followed him, and lifting one of Seltz's arms, let it drop suddenly. It fell to his side, lifeless. "He's sleeping like a log. The doctor must have given him a pretty stiff dose. I don't see how we are going to travel with him in this condition."

"Then we must leave him in the care of Monsieur Lefevre's other agents here in Brussels. We cannot delay an instant, on any account."

"I do not agree with you, monsieur. There is one thing which is as important to me as the recovery of the snuff box could possibly be to Monsieur de Grissac, and that is, the safety of my wife."

"Your wife?" Dufrenne stared at him in surprise.

"Yes, monsieur, my wife. She is at present in Dr. Hartmann's house. How she came there, I do not know, but I imagine that our friend the Prefect sent her there, to assist, if occasion offered, in our work. In that he was wise; but for her presence, I fear my plan would have failed. Had Seltz rung the doorbell, and been admitted by any of the doctor's servants, I doubt if I should have been able to get the box from him before the latter had seen him. I should then have been obliged to use force, and the results might have been disastrous."

"Yes, monsieur. I see that. The young lady at Dr. Hartmann's was sent by Monsieur Lefevre. His agents here have already informed me of that. But that she is your wife I did not know." He pondered for a moment, glancing at his watch. "It is a great pity. Delay may be most dangerous. Why do you not send her word to join you in Paris?"

Duvall frowned, and began to walk about the room nervously. "A few hours' delay can make no difference," he presently said. "The box is perfectly safe in our hands. I am not, however, at all convinced that my wife is perfectly safe in the hands of Dr. Hartmann."

"But he knows nothing?"

"That I cannot say. So far he does not, I think, suspect that Seltz was the man he expected from London. If he had, he would never have let me leave his office. Luckily for us, Seltz was a stranger to him, and with the murder of Noël on his conscience, he feared to say anything to the doctor about the snuff box while I was present. I imagine he suspected a trap of some sort. But the doctor will discover, probably before the day is out, how he has been tricked. Then he will begin to investigate, and if he finds out that it was my wife who admitted the man, he may in his rage decide to retaliate upon her. I cannot think of leaving Brussels, without her. She must go with me. Upon that I am determined."

Dufrenne looked grave, and a glint of anger came into his eyes. "The service of France, monsieur, is more important than your private affairs. I beg of you that you leave here at once."

"But why, my friend? We can leave just as well in the morning. The box is safe." He felt his waistcoat pocket.

"Safe, monsieur! Let me tell you that neither the box nor you yourself are safe for a moment, as long as you remain in Brussels. You would be in no greater danger, if you were carrying about with you a package of dynamite."

"You are unduly nervous, monsieur," laughed Duvall, as he observed the Frenchman's look of terror. "I have every confidence in my ability to take care of myself. I must notify my wife to join me here as soon as possible."

"How do you propose to do so?" inquired Dufrenne.

For a moment Duvall was puzzled. "You could not safely call her up by telephone," the Frenchman continued. "For her to leave the sanatorium now, in response to such a call, would attract the doctor's suspicion at once. He is probably quite well aware of the fact that she knows no one in Brussels. If he should have her followed here, and see her meet you, he would at once conclude that there was something wrong about the whole affair. He is very well known here in Brussels, and very powerful. Undoubtedly he would have you both arrested on some pretext. Once you are searched, and the snuff box taken from you, all our work is lost."

His earnest face, his frightened tones, disturbed the detective greatly. He saw the force of Dufrenne's arguments, yet the thought of leaving Grace to bear the brunt of Dr. Hartmann's anger was not to be considered for a moment. He looked out of the window in silence for a long time, trying to think out some plan that would insure Grace's safety. A gentle tapping at the door caused him to turn. He nodded to Dufrenne, who at once went to the door and opened it.

The newcomer proved to be Lablanche, of the Prefect's office, whom Dufrenne had met earlier in the day. He bowed to Duvall, who knew him slightly, then glanced at the sleeping figure on the bed. "You have been successful, monsieur?" he inquired eagerly.

Duvall nodded. "This fellow"—he indicated Seltz—"must be taken to London as soon as he is in condition to travel. We will leave the matter to you."

"Excellent, monsieur. He shall be well taken care of. I presume that you and Monsieur Dufrenne will start at once."

"I desire first, Monsieur Lablanche, to get my wife from the house of Dr. Hartmann."

Lablanche gave a low whistle. "I should not advise you to attempt to communicate with her, monsieur."

"You think her sudden departure would make Hartmann suspicious?"

"Undoubtedly."

"Then we must arrange for her to come to Brussels this afternoon on some pretext. If she only had some friends in the city—"

"The American Minister, monsieur!" exclaimed Lablanche, suddenly. "He recommended her to Dr. Hartmann. It appears that he was at one time acquainted with your wife's people. Perhaps he would undertake to telephone to her. That would be entirely safe. But I beg of you, monsieur, do not let the Minister know what your wife's object in going to Dr. Hartmann's was. He knows her only as Miss Ellicott. He vouched for her to Hartmann. If he knew that he had been used, it would make him extremely angry."

For a few moments Duvall stood in silent thought, then picking up his hat, went toward the door. "I will see the American Minister at once," he said, as he went out. "Wait for me here, gentlemen. I will be back within an hour."

Mr. Phelps, the United States Minister, was busy in his cabinet when Duvall was announced. He took the card from his secretary and glanced at it carelessly. The detective's name caused him to start. "Richard Duvall," he said aloud, to his secretary. "Surely it can't be the well-known detective, yet the name—" He regarded the card, his forehead wrinkled with thought. Duvall's distinguished position as the author of several works on the science of criminology was well known to him. "Show him in," he said, at length, and began to relight his cigar.

Duvall was ushered in, and in a few moments had explained the object of his visit. "A young lady—a Miss Ellicott," he told the Minister, "had come to Brussels the night before, and had gone to Dr. Hartmann's as a patient." Mr. Phelps nodded, and added that he had met Miss Ellicott, and had used his influence to enable her to obtain Dr. Hartmann's services. "The doctor is a great friend of mine," the Minister remarked. "I regard him as one of the leading scientists of Europe."

"Undoubtedly," the detective assented gravely. "I am not acquainted with him, myself. My business is with Miss Ellicott."

"Then why have you come here?" asked Mr. Phelps, with some asperity. "The doctor's house is but a few moments' drive."

"I know that. But unfortunately I am not acquainted with Miss Ellicott. She might resent my calling on her so unceremoniously. I had hoped that you might ask her to come here, so that I might be properly introduced to her."

The Minister considered the matter carefully. Evidently he did not altogether like it. "You forget, Mr. Duvall," he said, finally, "that I myself do not know you. Furthermore I certainly have no desire to involve Miss Ellicott in any difficulties. I trust," he concluded, uneasily, "that she is not already so involved."

"No." The detective shook his head. "Not yet. But unless I can have a few words with her in private, she soon may be. I am working in her interests. I am here to protect her from a grave danger." He went toward the Minister, and, taking a package of papers from his pocket, placed them in the latter's hand. "Here are my credentials. From them you will see that I am what I represent myself to be. I cannot undertake to explain to you now the reasons which prevent me from going to Miss Ellicott where she is. The mere fact that I am unknown to her will, I trust, prove sufficient. I wish to say to her but a few words. She will be very glad to hear them, I know."

The Minister returned the papers to Duvall and glanced at the clock upon his desk. "We are having a few friends for dinner to-night, Mr. Duvall. I shall ask Miss Ellicott to join us. If you care to be one of the party—" He paused, looking at the other questioningly.

"I shall be very glad indeed to accept, Mr. Phelps. I assure you that I would under no circumstances force myself upon you in this way, were it not for Miss Ellicott's good. And, in order that your other guests may not by any chance identify me, may I ask that you will introduce me as Mr. Brooks?"

The Minister nodded. "Very well, if you wish it, Mr. Duvall. The whole affair strikes me as extremely unusual, and did I not know you to be a man of your word, I should have nothing to do with it. Under the circumstances, I will consent. At least, I feel sure that no harm can come to Miss Ellicott while she is under my roof."

The detective murmured his thanks. "You will be doing Miss Ellicott a great service, my dear sir," he said. "And one thing more. When you telephone to her, asking her to come, kindly do not mention the fact that I have called." He took the Minister's hand and pressed it warmly. "Some day you will realize the dangers with which Miss Ellicott is being threatened."

On his return to the Hotel Metropole, Duvall found everything as he had left it. Seltz was still sleeping soundly. Lablanche was reading a newspaper. Dufrenne was superintending the placing of Duvall's portmanteau, which had arrived from Paris in response to a hasty wire from him that morning. He had been without a change of linen since the day before, and the arrival of his baggage was gratifying.

He informed Lablanche of his plans. "I shall dine at the United States Minister's," he informed them, "as Mr. Brooks. After dinner I shall ask Miss Ellicott's permission to escort her home. We will take a cab and drive to the railway station in time for the midnight train for Paris. On my arrival there, I shall give the snuff box to Monsieur Lefevre, who will see that it is safely returned to the Ambassador in London. You, Lablanche, can go to London with Seltz as soon as the latter is sufficiently recovered to travel—in the morning, let us say. You, Dufrenne, will no doubt prefer to return with me to Paris. In that event, kindly settle with the hotel people for these rooms, and join me at the railway station." He paused, opened his traveling case, and drew out a suit of evening clothes.

Lablanche and Dufrenne withdrew into the adjoining room, where Seltz lay sleeping. The latter paused in the door as he went out. "Take care of the snuff box," he said, pointedly. "Remember—the honor of France."

Grace Duvall went to her room, at Dr. Hartmann's, after her husband's departure, her feelings divided between her joy at his success—for she felt that his departure with Seltz meant success—and her sorrow at seeing him leave her, without so much as a single glance. She felt certain that she would hear from him during the course of the afternoon, and after eating her luncheon, sat down to read a book.

The afternoon seemed interminable. When at last she could bear the inaction no longer, she rose, put on her hat, and started down the stairs. As she reached the hall, one of the attendants came up to her. "Someone wishes to speak to you at the telephone, Miss Ellicott," the woman said.

Grace hurried to the 'phone, which was placed in a small recess half-way down the hall. The woman accompanied her, and stood near by as she took up the receiver. Clearly she was listening. Grace determined to speak with caution. It was undoubtedly Richard calling.

When she at last made out that it was the American Minister, Mr. Phelps, who was speaking, she felt a keen sense of disappointment. She learned that he and his wife wished her to come in and dine with them. At first she refused, fearful least by going into Brussels she might miss some word from Richard. Mr. Phelps was insistent. They counted on her. He would not take a denial. The thought occurred to her, momentarily, that possibly Richard had taken this means of communicating with her. The idea seemed far fetched, and yet—she heard Mr. Phelps' voice, urging her to come, and rather half-heartedly she agreed to do so. "The United States Minister, Mr. Phelps, and his wife, have asked me to dine with them to-night," she said to the attendant. "Will you be so good as to have a cab here for me at half-past seven?"

The woman bowed. "Certainly, mademoiselle," she said, and moved aside as Dr. Hartmann came along the hall.

Grace thought that he looked both puzzled and angry. He assumed a pleasant expression as he saw her, however, and when he spoke she knew he had overheard what she had just said. "Dining at the Minister's to-night?" he remarked, as he paused for a moment. "A charming man, Mr. Phelps. I may look in later, myself, and bring you home." He passed on, his face at once resuming the angry scowl which Grace had marked as he approached her.

She returned to her room, and began her toilette for the evening. The small trunk she had brought from Paris contained but a limited wardrobe—she had not expected anything in the way of social engagements, in this work that Monsieur Lefevre had assigned to her. A gown of black satin, however, trimmed with silver, she had put in at the last moment. It was very becoming—Richard had never seen her in it—she hoped he might come to her, before the evening was over. She half-made up her mind to speak to Mr. Phelps about it—to ask him to telephone to the hotels and attempt to locate Richard for her. Then the thought came to her that she had represented herself to the Minister as Miss Ellicott. Clearly it would never do to let Mr. Phelps know that she had deceived him.

She arrived at the house early, and after being introduced to Mrs. Phelps, went to the latter's room to remove her wraps, and to talk over their mutual acquaintances. None of the other guests had as yet arrived. Grace talked to Mrs. Phelps as brightly as she could, but her mind was intent upon Richard, and she wondered when and how she would hear from him.

Duvall, meanwhile, had been engaged in changing his clothes. When he at last put on the white waistcoat of his evening suit, he took up the one he had worn during the day and removed from it the ivory snuff box which had been the cause of his interrupted honeymoon. He glanced at the thing carelessly, before placing it in his waistcoat pocket, and as he did so, he fancied he detected a slight noise in the corridor without. In a moment he had thrown open the door which led to the hall. A man—evidently one of the hotel servants—was just rising from his knees, a small brush in one hand, a dust pan in the other.

Duvall looked at him sharply. The man bowed, smiling in a stupid way, then began to withdraw, explaining that he was cleaning the hall, and hoping that he had not disturbed "monsieur." The detective closed the door, uncertain whether the man had been watching him or not. He remembered Dufrenne's warning, and realized that in going out, alone, this night, he ran some chances of having the snuff box taken from him. Of course, it was unlikely that Dr. Hartmann had any suspicions of him—yet it seemed advisable to put the box in as safe a place as possible, at least until he was once more across the French frontier. Yet where could he put it? To secrete the thing in his room was out of the question. The place might be searched, for all he knew, within half an hour of his leaving it. To conceal it successfully about his person seemed equally impossible. Where, indeed, could he hope to hide an object of this size, so as to defy a search, in case one should be made? His eyes suddenly fell upon the opera hat which he had taken from his portmanteau. He took it up and gazed at it with a smile, then quickly whipped out his knife and began, with great care, to detach the inner lining of the crown for a distance of perhaps three or four inches. Carefully drawing back the lining, he slipped the thin ivory box beneath it, and pushed it back into place. The lining was of heavy black silk, stiffened by the label of the maker which was glued to it. The space between it and the crown was considerable. When Duvall had once more fastened the silk in place with the aid of a needle and thread which he drew from his dressing case, it would have required a very careful inspection, indeed, to have discovered that there was anything unusual about the hat. Even the added weight of the box was not perceptible—its lightness prevented that. When he had completed his task, the detective suddenly threw open the door and glanced into the hall. It was vacant. Evidently he had not been observed.

There were but four guests at the Minister's that night, of whom Duvall and Grace were two. The other two were a Mr. and Mrs. Haddon, friends of Mrs. Phelps, who were making a short stay in the Belgian capital on their way to their home in London.

The little party, with the exception of Duvall, had already assembled in the drawing-room, awaiting his arrival. Grace found the Haddons charming and cultivated people who had traveled all over the world, owing to Mr. Haddon's connection with the English Consular service. Mr. Phelps had told Grace that they were expecting an American, a friend of his, whose name was Brooks, but she did not exhibit much interest in the matter. She was becoming more and more worried about Richard, and wondered if he could, by any possibility, have left Brussels without communicating with her. The thought seemed unbelievable.

Dinner was set for eight. As the hour was striking, the butler announced Mr. Brooks. Grace glanced up carelessly as the latter entered, then her face went white, and she started forward with a glad cry. Mr. Phelps, who was mumbling an introduction, did not, luckily, observe her agitation. Duvall looked at her coolly. "Good-evening, Miss Ellicott," he said, bowing. "I am delighted to meet you."

The shock of the thing almost unnerved her. "Mr. Brooks," she managed to gasp, her face crimson. In a moment she became calmer, as she observed her husband's warning look, and began to chat with him nervously, as though he were the chance acquaintance he pretended to be. In a moment they all were seated about the dinner-table. He had been able to say to her as they left the drawing-room, however, unheard by the others, "I will ask permission to escort you home." She nodded, with a twinkle in her eyes. All her nervousness and anxiety had left her now, and in their place came a delicious feeling of happiness at Richard's presence, and a keen sense of adventure that made the blood tingle through her whole body. "Mr. Brooks!" She laughed inwardly at the thought that no one at the table but themselves knew that they were husband and wife. She proceeded to enter into the spirit of the occasion with huge delight, questioning Mr. Brooks about his business in Brussels with a keen sense of mischief.

It was along toward the middle of dinner that one of the servants came in and handed Mr. Phelps a card. Duvall, engaged for the moment in conversation with Mrs. Haddon, did not perceive it, but Grace, who sat next to their host, experienced a sudden feeling of alarm. She observed the Minister's puzzled face, as he excused himself and left the table, and for an instant she thought of warning Richard. A moment's thought, however, convinced her of the uselessness of the attempt, nor did she indeed know what she could say to him. She remembered Dr. Hartmann's remark, that he might look in at the Minister's after dinner, to which she had attached no importance at the time. Now the thought came to her that the doctor was in the reception-room without, and that his coming, at this time, in the middle of dinner, meant that some disaster was impending.

In a few moments Mr. Phelps reëntered the room, followed by Dr. Hartmann. The latter was in evening clothes, and his face seemed peculiarly forbidding and grim.

"Dr. Hartmann has consented to join us," he said to his wife. "Philippe"—he turned to the butler—"lay another place." Then he proceeded to introduce Hartmann to Mr. and Mrs. Haddon and to Duvall.

The latter looked at the doctor calmly. "I think we have met before, Doctor," he said, in an even voice.

"Quite so." Hartmann's face showed not a trace of emotion of any sort. "I hope your servant is better."

"He's still asleep," laughed the detective, then explained to the others, in a few words, his adventure of the morning. He saw that the Minister was puzzled, but the latter said nothing, at the time, and in a few moments the matter was forgotten. Only Grace showed any signs of alarm—Duvall went calmly on with his dinner as though nothing had happened. He spoke to her only occasionally and then addressed her with the formal politeness of a total stranger.

Dr. Hartmann was observing him intently under cover of a spirited conversation with Mrs. Phelps. It was clear to Grace that he could not quite understand why Duvall, or Brooks, as he supposed him to be, was dining here at the Minister's.

It was quite late when the party rose from the table, and, a little while later, Grace, anxious to get away from the place, and be alone with Richard, announced that she must return home. "Mr. Brooks has kindly offered to escort me," she said, quickly, fearful that Dr. Hartmann might suggest that she return with him.

The latter smiled coldly, his eyes fixed on her with a gleam of suspicion. "I think I shall be going myself," he said, as he took leave of the remainder of the party.

As they reached the sidewalk, Duvall observed the taxicab he had ordered to be in readiness, standing in front of the door. He helped Grace inside, then turned in some hesitation to the chauffeur. He dared not tell the fellow to drive to the railway station, since Hartmann, who stood beside the cab chatting with Grace, would inevitably hear him. He therefore instructed the man to go to Dr. Hartmann's with the intention of countermanding the order a little later, as soon as they had got out of earshot of the house. He threw open the door, entered the cab, and was about to pull the door shut after him when he felt his wrist seized from behind in a powerful grasp, and before he realized what had happened, Dr. Hartmann had stepped into the cab and closed the door. The chauffeur at once started off at a great rate.

"I'm sure, Mr. Brooks," said the doctor, suavely, as he sat down in the forward seat, his right hand still grasping Duvall's wrist, "that you will not mind taking me home with you. It is a long walk, and I fear there are no other taxicabs in sight."

Duvall looked at him sternly, then attempted to draw away his hand. "What do you mean, monsieur," he asked, harshly, "by detaining me in this manner?" He again tried to free his wrist, but the doctor was too strong for him.

Hartmann smiled pleasantly. "I feared, Mr. Brooks," he said, "that you might be tempted to use the revolver which you have in the pocket of your coat." He reached over quickly with his other hand and drew the revolver from the detective's pocket.

Grace, through all this, had said absolutely nothing. She realized how fatal any interruption by herself might be. She did not know of her husband's intention to leave Brussels that night. She had heard him order the chauffeur to drive to the sanatorium. Perhaps he wished her to return there. In that event, it was imperative that Dr. Hartmann should not know that the supposed Mr. Brooks and herself were anything but the most chance acquaintances.

"Doctor," she cried out, "what are you doing?"

"It seems that Dr. Hartmann has suddenly lost his senses, Miss Ellicott," exclaimed Duvall angrily.

"Quite so, my friend," said the doctor, sarcastically. "Just as our poor friend Seltz lost his. Don't try anything like that," he snarled, suddenly, as Duvall attempted to release his arm with a sudden twist. "I have a few questions I desire to ask you, Mr. Brooks."

"Questions? What are they?"

"I cannot possibly ask them here, in the presence of Miss Ellicott. Perhaps you will oblige me by stepping into my office for a few moments when we arrive at our destination."

"I can spare you five minutes," said Duvall, sullenly. He could not help remembering Dufrenne's advice, and regretted bitterly that he had not followed it. He had been prepared for almost any contingency. As he left the Minister's house, his hand clutched a revolver in the pocket of his coat. There seemed no way in which Hartmann could prevent him from taking Grace to the railway station. He felt so sure of this that he became overconfident. One moment only had he been off guard—the moment when, with his back to Hartmann, he had stepped into the cab. And the latter, seizing upon that instant's slip, had turned the tables upon him so completely that he cursed himself in his chagrin. Here he was, headed for Dr. Hartmann's house, on the outskirts of the town. Once there, the latter's attendants could easily overpower him and carry him into the place helpless. There seemed no possible means of escape. He determined to brazen the matter out, and meet Hartmann on his own ground. Resistance would at this juncture be useless. He congratulated himself that Grace had, by her cleverness, not shown her hand. The doctor evidently did not suspect, at least not very strongly, that she was anything other than she seemed—a patient. He knew he would be searched, and hoped that the place of concealment of the snuff box would defy even Hartmann. After that, he would demand his release, and rely upon Mr. Phelps to get it for him.

He lifted his head and saw that they were at the house. Without loosening his hold upon Duvall's arm, the doctor called to the chauffeur, "Ring the bell." The latter did so. In a moment, a servant appeared. "Send Max and Rudolph here," cried Hartmann, and presently two husky young Germans came out of the house. Hartmann spoke a few quick words to them in their own language and they ranged themselves on either side of the cab door. Then the doctor threw it open, and released the detective's wrist. "Get out, if you please, Mr. Brooks," he said, with a sardonic smile.