"I want to go to Margot's again to-day," volunteered Miss Kendall the following morning, adding with a smile, "You see, I've got the habit. Really, though, there is a mystery about that place that fascinates me. I want to find out more about this Marie, or Margot, or whoever it was that I thought I heard there. And then those doped cigarettes interest me. You see, I haven't forgotten what you said about dope the first time we talked about Dr. Harris. They will be more free with me, too, now that I am no longer a stranger."

"That is a good idea," agreed Kennedy, who was now chafing under the enforced inaction of the case. "I hope that this time they will let you into some of the secrets. There is one thing, though, I wish you'd look out for especially."

"What do you mean?" she asked.

"I should like to know what ways there are of communicating with the outside. You realize, of course, that it is very easy for them, if they come to suspect you, to frame up something in a place like that. There are strong-arm women as well as men, and I'm not at all sure that there may not be some men besides Dr. Harris who are acquainted with that place. At any rate Dr. Harris is unscrupulous enough himself."

"I shall make it a point to observe that," she said as she left us. "I hope I'll have something to tell you when I come back."

"Walter," remarked Craig as the door closed, "that is one of the gamest girls I ever knew."

I looked across at him inquiringly.

"Don't worry, my boy," he added, reading my expression. "She's not of the marrying kind, any more than I am."

The morning passed and half of the afternoon without any word from Miss Kendall. Kennedy was plainly becoming uneasy, when a hurried footstep in the hall was followed by a more hurried opening of the door.

"Let me sit down, just a minute, to collect myself," panted Miss Kendall, pressing her hands to her temples where the blue veins stood out and literally throbbed. "I'm all in."

"Why, what is the matter?" asked Kennedy, placing a chair and switching on an electric fan, while he quickly found a bottle of restorative salts which was always handy for emergencies in the laboratory.

"Oh—such a time as I've had! Wait—let me see whether I can recollect it in order."

A few minutes later she resumed. "I went in, as before. There seemed to be quite a change in the way they treated me. I must have made a good impression the first time. A second visit seemed to have opened the way for everything. Evidently they think I am all right.

"Well, I went through much the same thing as I did before, only I tried to make it not quite so elaborate, down to the point where several of us were sitting in loose robes in the lounging-room. That was the part, you know, that interested me before.

"The maid came in with the cigarettes and I smoked one of the doped ones. They watch everything that you do so closely there, and the moment I smoked one they offered me another. I don't know what was in them, but I fancy there must be just a trace of opium. They made me feel exhilarated, then just a bit drowsy. I managed to make away with the second without inhaling much of the smoke, for my head was in a whirl by this time. It wasn't so much that I was afraid I couldn't take care of myself as it was that I was afraid that it would blunt the keenness of my observation and I might miss something."

"Besides the cigarettes, was there anything else?" asked Craig.

"Yes, indeed. I didn't see anyone there I recognized, but I heard some of them talk. One was taking a little veronal; another said something about heroin. It was high-toned hitting the pipe, if you call it that—a Turkish bath, followed by massage, and then a safe complement of anything you wanted, taken leisurely by these aristocratic dope fiends.

"There was one woman there who I am sure was snuffing cocaine. She had a little gold and enamelled box like a snuff box beside her from which she would take from time to time a pinch of some white crystals and inhale it vigorously, now and then taking a little sip of a liqueur that was brought in to her."

"That's the way," observed Kennedy. "There are always a considerable number of inhuman beings who are willing to make capital out of the weaknesses of others. This illicit sale of cocaine is one example. Such conditions have existed with the opium products a long time. Now it seems to be the 'coke fiend.'"

"I was glad I did just as I did," resumed Clare, "because it wasn't long before I saw that the thing to do was to feign drowsiness. A maid came over to me and in a most plausible and insinuating way hinted that perhaps I might feel like resting and that if the noise in the beauty parlour annoyed me, they had the entire next house—the one next to the Montmartre, you know—which had been fitted up as a dormitory."

"You didn't go?" cut in Craig immediately.

"I did not. I pleaded an engagement. Why, the place is a regular dope joint."

"Exactly. I suspected as much as you went along. Everything seems to have moved uptown lately, to have been veneered over to meet the fastidious second decade of the twentieth century. But underneath it all are the same old vices. I'm glad you didn't attempt to go into the next house. Anyhow, now we are certain about the character of the place. Did you notice anything about the means of communicating with the outside—the telephones, for instance?"

Miss Kendall was evidently feeling much better now.

"Oh, yes," she answered. "I took particular care to observe that. They have a telephone, but there is a girl who attends to it, although they don't really need one. She listens to everything. Then, too, in the other house—You remember I spoke about the girl whom we saw paying Ike the Dropper? It seems that she has a similar position at the telephone over there."

"So they have two telephones," repeated Craig.

"Yes."

"Good. There are always likely to be some desperate characters in places like that. If we ever have anyone go into that dope joint we must have some way of keeping in touch and protecting the person."

Miss Kendall had gone home for a few hours of rest after her exciting experience. Craig was idly tapping with his fingers on the broad arm of his chair.

Suddenly he jumped up. "I'm going up there to look that joint over from the outside," he announced.

We walked past the front of it without seeing anything in particular, then turned the corner and were on the Avenue. Kennedy paused and looked at a cheap apartment house on which was a sign, "Flats to Let."

"I think I'll get the janitor to show me one of them," he said.

One was on the first floor in the rear. Kennedy did not seem to be very much interested in the rent. A glance out of the window sufficed to show him that he could see the back of the Montmartre and some of the houses. It took only a minute to hire it, at least conditionally, and a bill to the janitor gave us a key.

"What are you going to do?"

"We can't do anything just yet, but it will be dark by the time I get over to the laboratory and back and then we can do something."

That night we started prowling over the back fences down the street. Fortunately it was a very black night and Craig was careful not to use even the electric bull's-eye which he had brought over from the laboratory together with some wire and telephone instruments.

As we crouched in the shadow of one of the fences, he remarked: "Just as I expected; the telephone wires run along the tops of the fences. Here's where they run into 72—that's the beauty parlour. These run into 70—that's the dope joint. Then next comes the Montmartre itself, reaching all the way back as far as the lot extends."

We had come up close to the backs of the houses by this time. The shades were all drawn and the blinds were closed in both of them, so that we had really nothing to fear provided we kept quiet. Besides the back yards looked unkempt, as if no one cared much about them.

Kennedy flashed the electric bull's-eye momentarily on the wires. They branched off from the back fence down the party fence to the houses, both sets on one fence.

"Good!" he exclaimed. "It is better than I hoped. The two sets go on up to the first floor together, then separate. One set goes into the beauty parlour; the other into the dope joint."

Craig had quietly climbed up on a shed over the basements of both the houses. He was working quickly with all the dexterity of a lineman. To two of the four wires he had attached one other. Then to two others he attached another, all the connections being made at exactly corresponding points.

The next step was to lead these two newly connected wires to a window on the first floor of the house next to the Montmartre. He fastened them lightly to the closed shutter, let himself down to the yard again and we beat a slow and careful retreat to our flat.

In one of the yards down near the corner, however, he paused. Here was an iron box fastened to one of the fences, a switch box or something of the sort belonging to the telephone company. To it were led all the wires from the various houses on the block and to each wire was fastened a little ticket on which was scrawled in indelible pencil the number of the house to which the wire ran.

Kennedy found the two pairs that ran to 70 and 72, cut in on them in the same way that he had done before and fastened two other wires, one to each pair. This pair he led along and into the flat.

"I've fixed it," he explained, "so that anyone who can get into that room on the back of the first floor of the dope joint can communicate with the outside very easily over the telephone, without being overheard, either."

"How?" I asked completely mystified by the apparent simplicity of the proceeding.

"I have left two wires sticking on the outside shutter of that room," he replied. "All that anyone who gets into that room has to do is to open the window softly, reach out and secure them. With them fastened to a transmitter which I have, he can talk to me in the flat around the corner and no one will ever know it."

There was nothing more that we could do that night and we waited impatiently until Clare Kendall came to make her daily report in the morning.

"The question is, whom are we going to get whom we can trust to go to that dope joint and explore it?" remarked Kennedy, after we had finished telling Miss Kendall about our experiences of the night before.

"Carton must have someone who can take a course in beauty and dope," I replied. "Or perhaps Miss Kendall has one of her investigators whom she can trust."

"If the thing gets too rough," added Craig, "whoever is in there can telephone to us, if she will only be careful first to get that back room in the 'dormitory,' as they call it. Then all we'll have to do will be to jump in there and—-"

"I'll do it," interrupted Clare.

"No, Miss Kendall," denied Kennedy firmly.

"Let me do it. There is no one whom I can trust more than myself.
Besides, I know the places now."

She said it with an air of quiet determination, as if she had been thinking it over ever since she returned from her visit of the day before.

Kennedy and Miss Kendall faced each other for a moment. It was evident that it was against just this that he had been trying to provide. On her part it was equally evident that she had made up her mind.

"Miss Kendall," said Kennedy, meeting her calm eye, "you are the most nervy detective, barring none, that it has ever been my pleasure to meet. I yield under protest."

I must say that it was with a great deal of misgiving that I saw Clare enter Margot's. We had gone as far as the corner with her, had watched her go in, and then hurried into the unfurnished apartment which Craig had rented on the Avenue.

As we sat on the rickety chairs which we had borrowed from the janitor under pretence of wanting to reach something, the minutes that passed seemed like hours.

I wondered what had happened to the plucky girl in her devotion to the cause in which she had enlisted, and several times I could see from the expression of Craig's face that he more and more regretted that he had given in to her and had allowed her to go, instead of adhering to his original plan. From what she had told us about the two places, I tried to imagine what she was doing, but each time I ended by having an increased feeling of apprehension.

Kennedy sat grimly silent with the receiver of the telephone glued to his ear, straining his hearing to catch even the faintest sound.

At last his face brightened.

"She's there all right," he exclaimed to me. "Managed to make them think in the beauty parlour that she was a dope fiend and pretty far gone. Insisted that she must have the back room on the first floor because she was afraid of fire. She kept the door open so that she would not miss anything, but it was a long time before she got a chance to reach out of the window and get the wires and connect them with the instruments I gave her. But it's all right now.

"Yes, Miss Kendall, right here, listening to everything you get a chance to say. Only be careful. There is no use spoiling the game by trying to talk to me until you have all that you think you can obtain in the way of evidence. Don't let them think you have any means of communication with the outside or they'll go to any length to silence you. We'll be here all the time and the moment you think there is any danger, call us."

Kennedy seemed visibly relieved by the message.

"She says that she has found out a great deal already, but didn't dare take the time to tell it just yet," he explained. "By the way, Walter, while we are waiting, I wish you would go out and see whether there is a policeman on fixed post anywhere around here."

Five minutes later when I returned, having located the nearest peg post a long block away on Broadway, Kennedy raised a warning hand. She was telephoning again.

"She says that attendants come and go in her room so often that it's hard to get a chance to say anything, but she is sure that there is someone hidden there, perhaps Marie or Madame Margot, whoever she is, or it may even be Betty Blackwell. They watch very closely."

"But," I asked, almost in a whisper, as if someone over there might hear me, "isn't this a very dangerous proceeding, Craig? It seems to me you are taking long chances. Suppose one of the telephone girls in either house, whom she told us keep such sharp watch over the wires, should happen to be calling up or answering a call. She would hear someone else talking over the wire and it wouldn't be difficult for her to decide who it was. Then there'd be a row."

"Not a chance," smiled Kennedy. "No one except ourselves, not even Central, can hear a word of what is said over these connections I have made. This is what is called a phantom circuit."

"A phantom circuit?" I repeated. "What kind of a weird thing is that?"

"It is possible to superimpose another circuit over the four telephone wires of two existing circuits, making a so-called phantom line," he explained, as we waited for the next message. "It seems fantastic at first, but it is really in accordance with the laws of electricity. You use each pair of wires as if it were one wire and do not interfere in the least with them, but are perfectly independent of both. The current for the third circuit enters the two wires of one of the first circuits, divides, reunites, so to speak, at the other end, then returns through the wires of the second circuit, dividing and reuniting again, thus just balancing the two divisions of the current and not causing any effect on either of the two original circuits. Rather wonderful, isn't it?"

"I should say that it was," I marvelled. "I am glad I see it actually working rather than have to believe it second hand."

"It's all due to a special repeating coil of high efficiency absolutely balanced as to resistances, number of turns of wire, and so on which I have used—Yes—Miss Kendall—we are here. Now please don't let things go on too far. At the first sign of danger, call. We can get in all right. You have the evidence now that will hold in any court as far as closing up that joint goes, and I'll take a chance of breaking into—well, Hades, to get to you. Good-bye.

"I guess it is Hades there," he resumed to me. "She has just telephoned that one of the dope fiends upstairs—a man, so that you see they admit both men and women there, after all—had become violent and Harris had to be called to quiet him before he ran amuck. She said she was absolutely sure, this time at least, that it was Harris. As I was saying about this phantom circuit, it is used a good deal now. Sometimes they superimpose a telephone conversation over the proper arrangement of telegraph messages and vice versa.

"What's that?" cried Craig, suddenly breaking off. "They heard you talking that last time, and you have locked the door against them? They are battering it down? Move something heavy, if you can, up against it—the bureau, anything to brace it. We'll be there directly. Come on, Walter. There isn't time to get around Broadway for that fixed post cop. We must do it ourselves. Hurry."

Craig dashed breathlessly out on the street. I followed closely.

"Hurry," he panted. "Those people haven't any use for anyone that they think will snitch on them."

As we turned the corner, we ran squarely into a sergeant slowly going his rounds with eyes conveniently closed to what he was paid not to see.

Kennedy stopped and grabbed his arm.

"There's a girl up here in 72 who is being mistreated," he cried.
"Come. You must help us get her out."

"Aw, g'wan. Whatyer givin' us? 72? That's a residence."

"Say—look here. I've got your number. You'll be up on the most serious charges of your whole career if you don't act on the information I have. All of Ike the Dropper's money'll go for attorney's fees and someone will land in Sing Sing. Now, come!"

We had gained the steps of the house. Outside all was dark, blank, and bare. There was every evidence of the most excessive outward order and decency—not a sign of the conflict that was raging within.

Before the policeman could pull the bell, which would have been a first warning of trouble to the inmates, Kennedy had jumped from the high stoop to a narrow balcony running along the front windows of the first story, had smashed the glass into splinters with a heavy object which he had carried concealed under his coat, and was engaged in a herculean effort to wrench apart some iron bars which had been carefully concealed behind the discreetly drawn shades.

As one yielded, he panted, "No use to try the door. The grill work inside guards that too well. There goes another."

Inside now we could hear cries that told us that the whole house was roused, that even the worst of the drug fiends had come at least partly to his senses and begun to realize his peril. From Margot's beauty parlour a couple of girls and a man staggered forth in a vain effort to seem to leave quietly.

"Close that place, too, officer," cried Kennedy to the now astounded policeman. "We'll attend to this house."

The sergeant slowly lumbered across in time to let two more couples escape. It was evident that he hated the job; indeed, would have arrested Kennedy in the old days before Carton had thrown such a scare into the grafters. But Kennedy's assurance had flabbergasted him and he obeyed.

Another bar yielded, and another. Together we squeezed in and found ourselves in a dark front parlour. There was nothing to distinguish it from any ordinary reception room in the blackness.

Hurried footsteps were heard as if several people were retreating into the next house. Down the hall we hastened to the back room.

A second we listened. All was silent. Was Clare safe? It looked ominous. Still the door, partly battered in, was closed.

"Miss Kendall!" called Craig, bending down close to the door.

"Is it you, Professor Kennedy?" came back a faint voice from the other side.

"Yes. Are you all right?"

There was no answer, but she was evidently tugging at something which appeared to be a heavy piece of furniture braced against the door. At last the bolt was slipped back, and there in the doorway she swayed, half exhausted but safe.

"Yes, all right," murmured Clare, bracing herself against the chiffonier which she had moved away from the door, "just a little shaky from the drugs—but all right. Don't bother about me, now. I can take care of myself. I'll feel better in a minute. Upstairs—that is where I think that woman is. Please, please don't—I'm all right—truly. Upstairs."

Kennedy had taken her gently by the arm and she sank down in an easy chair.

"Please hurry," she implored. "You may be too late."

She had risen again in spite of us and was out in the lower hall. We could hear a footstep on the stairs.

"There she goes, the woman who has been hiding up there, Madame—"

Clare cut the words short.

A woman had hastily descended the steps, evidently seeing her opportunity to escape while we were in the back of the house. She had reached the street door, which now was open, and the flaming arc light in front of the house shone brightly on her.

I looked, expecting to see our dark-haired, olive-skinned Marie. I stared in amazement. Instead, this woman was fair, her hair was flaxen, her figure more slim, even her features were different. She was a stranger. I could not recollect ever having seen her.

Again I strained my eyes, thinking it might be Betty Blackwell at last, but this woman bore no resemblance apparently to her. She looked older, more mature.

In my haste I noted that she had a bandage about her face, as if she had been injured recently, for there seemed to be blood on it where it had worked itself loose in her flight. She gave one glance at us, and quickened her pace at seeing us so close. The bandage, already loose, slipped off her face and fell to the floor. Still she did not seem other than a stranger to me, though I had a half-formed notion that I had seen that face somewhere before. She did not stop to pick the bandage up. She had gained the door and was down the front step on the sidewalk before we could stop her.

Taxicabs in droves seemed to have collected, like buzzards over a dead body. They were doing a thriving business carrying away those who sought to escape. Into one by which a man was waiting in the shadow the woman hurried. The man looked for all the world like Dr. Harris. An instant later the chauffeur was gone.

The policeman had the front door of Madame Margot's covered all right, so efficiently that he was neglecting everything else. From the basement now and then a scurrying figure catapulted itself out and was lost in the curious crowd that always collects at any time of day or night on a New York street when there is any excitement.

"It is of no use to expect to capture anyone now," exclaimed Craig, as we hurried back into the dope joint. "I hardly expected to do it. All I panted was to protect Miss Kendall. But we have the evidence against this joint that will close it for good."

He stooped and picked up the bandage.

"I think I'll keep that," he remarked thoughtfully. "I wonder what that blonde woman wore that for?"

"She MUST be up there," reiterated Clare, who had followed us. "I heard them talking, it seemed to me only the moment before I heard you in the hall."

The excitement seemed now to have the effect of quieting her unstrung nerves and carrying her through.

"Let us go upstairs," said Kennedy.

From room to room we hurried in the darkness, lighting the lights. They were all empty, yet each one gave its mute testimony to the character of its use and its former occupants. There were opium lay-outs with pipes, lamps, yen haucks, and other paraphernalia in some. In others had been cocaine snuffers. There seemed to be everything for drug users of every kind.

At last in a small room in front on the top floor we came upon a girl, half insensible from a drug. She was vainly trying to make herself presentable for the street, ramblingly talking to herself in the meantime.

Again my hopes rose that we had found either the mysterious Marie Margot or Betty Blackwell. A second glance caused us all to pause in surprise and disappointment.

It was the Titian-haired girl from the Montmartre office.

Miss Kendall, recovering from the effects of the drugs which she had been compelled to take in her heroic attempt to get at the dope joint, was endeavouring to quiet the girl from the Montmartre, who, now vaguely recollecting us, seemed to realize that something had gone wrong and was trembling and crying pitifully.

"What's the matter with her?" I asked.

"Chloral," replied Miss Kendall in a low voice aside. "I suppose she has had a wild night which she has followed by chloral to quiet her nerves, with little effect. Didn't you ever see them? They will go into a drug store in this part of the city where such things are sold, weak, shaky, nervous wrecks. The clerk will sell them the stuff and they will retire for a moment into the telephone booth. Sometimes they will come out looking as though they had never felt a moment's effect from their wild debauches. But there are other times when they are too weakened to get over it so quickly. That is her case, poor girl."

The soothing hand which she laid on the girl's throbbing head was quite in contrast with the manner in which I recalled her to have spoken of the girl when first we saw her at the Montmartre. She must have seen the look of surprise on my face.

"I can't condemn these girls too strongly when I see them themselves," she remarked. "It would be so easy for them to stop and lead a decent life, if they only would forget the white lights and the gay life that allures them. It is when they are so down and out that I long to give them a hand to help them up again and show them how foolish it is to make slaves of themselves."

"Call a cab, Walter," said Kennedy, who had been observing the girl closely. "There is nothing more that we can expect to accomplish here. Everybody has escaped by this time. But we must get this poor girl in a private hospital or sanitarium where she can recover."

Clare had disappeared. A moment later she returned from the room she had had downstairs with her hat on.

"I'm going with her," she announced simply.

"What—you, Miss Kendall?"

"Yes. If a girl ever needed a friend, it is this girl now. There is nothing I can do for the moment. I will take care of her in my apartment until she is herself again."

The girl seemed to half understand, and to be grateful to Clare. Kennedy watched her hovering over the drug victim without attempting to express the admiration which he felt.

Just as the cab was announced, he drew Miss Kendall aside. "You're a trump," he said frankly. "Most people would pass by on the other side from such as she is."

They talked for a moment as to the best place to go, then decided on a quiet little place uptown where convalescents were taken in.

"I think you can still be working on the case, if you care to do so," suggested Craig as Miss Kendall and her charge were leaving.

"How?" she asked.

"When you get her to this sanitarium, try to be with her as much as you can. I think if anyone can get anything out of her, you can. Remember it is more than this girl's rescue that is at stake. If she can be got to talk she may prove an important link toward piecing together the solution of the mystery of Betty Blackwell. She must know many of the inside secrets of the Montmartre," he added significantly.

They had gone, and Craig and I had started to go also when we came across a negro caretaker who seemed to have stuck by the place during all the excitement.

"Do you know that girl who just went out?" asked Craig.

"No, sah," she replied glibly.

"Look here," demanded Craig, facing her. "You know better than that. She has been here before, and you know it. I've a good mind to have you held for being in charge of this place. If I do, all the Marie Margots and Ike the Droppers can't get you out again."

The negress seemed to understand that this was no ordinary raid.

"Who is she?" demanded Craig.

"I dunno, sah. She come from next door."

"I know she did. She's the girl in the office of the Montmartre. Now, you know her. What is her name?"

The negress seemed to consider a moment, then quickly answered, "Dey always calls her Miss Sybil here, sah, Sybil Seymour, sah."

"Thank you. I knew you had some name for her. Come, Walter. This is over for the present. A raid without arrests, too! It will be all over town in half an hour. If we are going to do anything it must be done quickly."

We called on Carton and lost no time in having the men he could spare placed in watching the railroads and steamship lines to prevent if we could any of the gang from getting out of the city that way. It was a night of hard work with no results. I began to wonder whether they might not have escaped finally after all. There seemed to be no trace. Harris had disappeared, there was no clue to Marie Margot, no trace of the new blonde woman, not a syllable yet about Betty Blackwell.