Not used to Kennedy's peculiar methods, they were now on guard, ignorant of the fact that that alone was sufficient to corroborate unescapably any evidence they had already given of their feelings toward each other.

Kennedy passed lightly over the torn and bleeding heart of Eulalie. But, much as he disliked to do so, he could not so quickly pass Anitra. In spite of her grief, I could see that she was striving to control herself. A quick blush suffused her face and her breath came and went faster.

"This record," went on Kennedy, lowering his voice, "tells me that two men are in love with Anitra Barrios. I will not say which exhibits the deeper, truer passion. You shall see for yourself in a moment. But, more than that, it tells me which of the two she cares for most—a secret her heart would never permit her lips to disclose. Nor will I disclose it.

"One of them, with supreme egotism, was so sure that he would win her heart that he plotted this murder of her brother so that she would have the whole estate to bring to him—a terrible price for a dowry. My love meter tells me, however, that Anitra has something to say about it yet. She does not love this man.

"As for Teresa de Leon, it was jealousy that impelled her to follow Jose Barrios from Cuba to New York. The murderer, in his scheming, knew it, saw a chance to use her, to encourage her, perhaps throw suspicion on her, if necessary. When I came uncomfortably close to him he even sent an anonymous telegram that might point toward her. It was sent by the same person who stole in Barrios's office and shot him with an asphyxiating pistol which discharged a fatal quantity of pure veratrine full at him.

"My love meter, in registering hidden emotions, supplements what the polarimeter tells me. It was the levo-rotary veratrine of the fatal death camas which you used, Page," concluded Craig, as again the electric attachment clicked shut the lock on the laboratory door.



VIII

THE VITAL PRINCIPLE

"That's the handwriting of a woman—a jealous woman," remarked Kennedy, handing to me a dainty note on plain paper which had come in the morning mail.

I did not stop to study the writing, for the contents of the letter were more fascinating than even Kennedy's new science of graphology.

You don't know me [the note read], but I know of your work of scientific investigation.

Let me inform you of something that ought to interest you.

In the Forum Apartments you will find that there is some strange disease affecting the Wardlaw family. It is a queer disease of the nerves. One is dead. Others are dying.

Look into it.

A FRIEND.

As I read it I asked myself vainly what it could mean. There was no direct accusation against any one, yet the implication was plain. A woman had been moved by one of the primal passions to betray—some one.

I looked up from the note on the table at Craig. He was still studying the handwriting.

"It's that peculiar vertical, angular hand affected by many women," he commented, half to himself. "Even at a glance you can see that it's written hastily, as if under the stress of excitement and sudden resolution. You'll notice how those capitals—" The laboratory door opened, interrupting him.

"Hello, Kennedy," greeted Doctor Leslie, our friend, the coroner's physician, who had recently been appointed Health Commissioner of the city.

It was the first time we had seen him since the appointment and we hastened to congratulate him. He thanked us absently, and it was evident that there was something on his mind, some problem which, in his new office, he felt that he must solve if for no other purpose than to justify his reputation. Craig said nothing, preferring to let the commissioner come to the point in his own way.

"Do you know, Kennedy," he said, at length, turning in his chair and facing us, "I believe we have found one of the strangest cases in the history of the department."

The commissioner paused, then went on, quickly, "It looks as if it were nothing less than an epidemic of beriberi—not on a ship coming into port as so often happens, but actually in the heart of the city."

"Beriberi—in New York?" queried Craig, incredulously.

"It looks like it," reiterated Leslie, "in the family of a Doctor Wardlaw, up-town here, in the Forum—"

Kennedy had already shoved over the letter he had just received. Leslie did not finish the sentence, but read the note in amazement.

"What are the symptoms?" inquired Craig.

"What makes you think it is beriberi, of all things?"

"Because they show the symptoms of beriberi," persisted Leslie, doggedly. "You know what they are like. If you care to go into the matter I think I can convince you."

The commissioner was still holding the letter and gazing, puzzled, from it to us. It seemed as if he regarded it merely as confirming his own suspicions that something was wrong, even though it shed no real light on the matter.

"How did you first hear of it?" prompted Kennedy.

Leslie answered frankly. "It came to the attention of the department as the result of a reform I have inaugurated. When I went in office I found that many of the death certificates were faulty, and in the course of our investigations we ran across one that seemed to be most vaguely worded. I don't know yet whether it was ignorance—or something worse. But it started an inquiry. I can't say that I'm thoroughly satisfied with the amended certificate of the physician who attended Mrs. Marbury, the mother of Doctor Wardlaw's wife, who died about a week ago—Doctor Aitken."

"Then Wardlaw didn't attend her himself?" asked Kennedy.

"Oh no. He couldn't, under the circumstances, as I'll show you presently, aside from the medical ethics of the case. Aitken was the family physician of the Marburys."

Kennedy glanced at the note. "One is dead. Others are dying," he read. "Who are the others? Who else is stricken?"

"Why," continued Leslie, eager to unburden his story, "Wardlaw himself has the marks of a nervous affection as plainly as the eye can see it. You know what it is in this disease, as though the nerves were wasting away. But he doesn't seem half as badly affected as his wife. They tell me Maude Marbury was quite a beauty once, and photographs I have seen prove it. She's a wreck now. And, of course, the old lady must have been the most seriously affected of them all."

"Who else is there in the household?" inquired Kennedy, growing more and more interested.

"Well," answered Leslie, slowly, "they've had a nurse for some time, Natalie Langdale. Apparently she has escaped."

"Any servants?"

"Some by the day; only one regularly—a Japanese, Kato. He goes home at night, too. There's no evidence of the disease having affected him."

I caught Leslie's eye as he gave the last information. Though I did not know much about beriberi, I had read of it, and knew that it was especially prevalent in the Orient. I did not know what importance to attach to Kato and his going home at night.

"Have you done any investigating yourself?" asked Kennedy.

Leslie hesitated a moment, as though deprecating his own efforts in that line, though when he spoke I could see no reason why he should, except that it had so often happened that Kennedy had seen the obvious which was hidden from most of those who consulted him.

"Yes," he replied, "I thought perhaps there might be some motive back of it all which I might discover. Possibly it was old Mrs. Marbury's fortune—not a large one, but substantial. So it occurred to me that the will might show it. I have been to the surrogate."

"And?" prompted Kennedy, approvingly.

"Mrs. Marbury's will has already been offered for probate. It directs, among other things, that twenty-five thousand dollars be given by her daughter, to whom she leaves the bulk of her fortune, to Doctor Aitken, who had been Mr. Marbury's physician and her own."

Leslie looked at us significantly, but Kennedy made no comment.

"Would you like to go up there and see them?" urged the commissioner, anxious to get Craig's final word on whether he would co-operate in the affair.

"I certainly should," returned Kennedy, heartily, folding up the letter which had first attracted his interest. "It looks as if there were more to this thing than a mere disease, however unusual."

Doctor Leslie could not conceal his satisfaction, and without delaying a moment more than was necessary hurried us out into one of the department cars, which he had left waiting outside, and directed the driver to take us to the Forum Apartments, one of the newest and most fashionable on the Drive.

Miss Langdale met us at the door and admitted us into the apartment. She was a striking type of trained nurse, one of those who seem bubbling over with health and vivacity. She seemed solicitous of her patients and reluctant to have them disturbed, yet apparently not daring to refuse to admit Doctor Leslie. There was nothing in her solicitude, however, that one could take exception to.

Miss Langdale conducted us softly down a hallway through the middle of the apartment, and I noted quickly how it was laid out. On one side we passed a handsomely furnished parlor and dining- room, opposite which were the kitchen and butler's pantry, and, farther along, a bedroom and the bath. On down the hall, on the right, was Doctor Wardlaw's study, or rather den, for it was more of a library than an office.

The nurse led the way, and we entered. Through the windows one caught a beautiful vista of the Drive, the river, and the Jersey shore. I gazed about curiously. Around the room there were bookcases and cabinets, a desk, some easy-chairs, and in the corner a table on which were some of Wardlaw's paraphernalia, for, although he was not a practising physician, he still specialized in his favorite branches of eye and ear surgery.

Miss Langdale left us a moment, with a hasty excuse that she must prepare Mrs. Wardlaw for the unexpected visit. The preparation, however, did not take long, for a moment later Maude Wardlaw entered, supported by her nurse.

Her lips moved mechanically as she saw us, but we could not hear what she said. As she walked, I could see that she had a peculiar gait, as though she were always lifting her feet over small obstacles. Her eyes, too, as she looked at us, had a strange squint, and now and then the muscles of her face twitched. She glanced from Leslie to Kennedy inquiringly, as Leslie introduced us, implying that we were from his office, then dropped into the easy-chair. Her breathing seemed to be labored and her heart action feeble, as the nurse propped her up comfortably.

As Mrs. Wardlaw's hand rested on the arm of the chair I saw that there was a peculiar flexion of her wrist which reminded me of the so-called "wrist-drop" of which I had heard. It was almost as if the muscles of her hands and arms, feet and legs, were weak and wasting. Once she had been beautiful, and even now, although she seemed to be a wreck of her former self, she had a sort of ethereal beauty that was very touching.

"Doctor is out—just now," she hesitated, in a tone that hinted at the loss of her voice. She turned appealingly to Miss Langdale. "Oh," she murmured, "I feel so badly this morning—as if pins and needles were sticking in me—vague pains in all my limbs—"

Her voice sank to a whisper and only her lips moved feebly. One had only to see her to feel sympathy. It seemed almost cruel to intrude under the circumstances, yet it was absolutely necessary if Craig were to accomplish anything. Maude Wardlaw, however, did not seem to comprehend the significance of our presence, and I wondered how Kennedy would proceed.

"I should like to see your Japanese servant, Kato," he began, directly, somewhat to my surprise, addressing himself rather to Miss Langdale than to Mrs. Wardlaw.

The nurse nodded and left the room without a word, as though appreciating the anomalous position in which she was placed as temporary mistress of the household.

A few moments later Kato entered. He was a typical specimen of the suave Oriental, and I eyed him keenly, for to me East was East and West was West, and I was frankly suspicious, especially as I saw no reason to be otherwise in Kennedy's manner. I waited eagerly to see what Craig would do.

"Sit here," directed Kennedy, indicating a straight-backed chair, on which the Japanese obediently sat. "Now cross your knees."

As Kato complied, Kennedy quickly brought his hand, held flat and palm upward, sharply against the Jap's knee just below the kneecap. There was a quick reflex jerk of the leg below the knee in response.

"Quite natural," Kennedy whispered, turning to Leslie, who nodded.

He dismissed Kato without further questioning, having had an opportunity to observe whether he showed any of the symptoms that had appeared in the rest of the family. Craig and the Health Commissioner exchanged a few words under their breath, then Craig crossed the room to Mrs. Wardlaw. The entrance of Kato had roused her momentarily and she had been watching what was going on.

"It is a simple test," explained Kennedy, indicating to Miss Langdale that he wished to repeat it on her patient.

Mrs. Wardlaw's knee showed no reflex! As he turned to us, we could see that Kennedy's face was lined deeply with thought, and he paced up and down the room once or twice, considering what he had observed.

I could see that even this simple interview had greatly fatigued Mrs. Wardlaw. Miss Langdale said nothing, but it was plainly evident that she objected strongly to the strain on her patient's strength.

"That will be sufficient," nodded Craig, noticing the nurse. "Thank you very much. I think you had better let Mrs. Wardlaw rest in her own room."

On the nurse's arm Mrs. Wardlaw withdrew and I looked inquiringly from Kennedy to Doctor Leslie. What was it that had made this beautiful woman such a wreck? It seemed almost as though the hand of fate had stretched out against one who had all to make her happy—wealth, youth, a beautiful home—for the sullen purpose of taking away what had been bestowed so bounteously.

"It is polyneuritis, all right, Leslie," Craig agreed, the moment we were alone.

"I think so," coincided Leslie, with a nod. "It's the CAUSE I can't get at. Is it polyneuritis of beriberi—or something else?" Kennedy did not reply immediately.

"Then there are other causes?" I inquired of Leslie.

"Alcohol," he returned, briefly. "I don't think that figures in this instance. At least I've seen no evidence."

"Perhaps some drug?" I hazarded at a venture.

Leslie shrugged.

"How about the food?" inquired Craig. "Have you made any attempt to examine it?"

"I have," replied the commissioner. "When I came up here first I thought of that. I took samples of all the food that I could find in the ice-box, the kitchen, and the butler's pantry. I have the whole thing, labeled, and I have already started to test them out. I'll show you what I have done when we go down to the department laboratory."

Kennedy had been examining the books in the bookcase and now pulled out a medical dictionary. It opened readily to the heading, "Polyneuritis—multiple neuritis."

I bent over and read with him. In the disease, it seemed, the nerve fibers themselves in the small nerves broke down and the affection was motor, sensory, vasomotor, or endemic. All the symptoms described seemed to fit what I had observed in Mrs. Wardlaw.

"Invariably," the article went on, "it is the result of some toxic substance circulating in the blood. There is a polyneuritis psychosis, known as Korsakoff's syndrome, characterized by disturbances of the memory of recent events and false reminiscences, the patient being restless and disorientated."

I ran my finger down the page until I came to the causes. There were alcohol, lead, arsenic, bisulphide of carbon, diseases such as diabetes, diphtheria, typhoid, and finally, much to my excitement, was enumerated beriberi, with the added information, "or, as the Japanese call it, kakke."

I placed my finger on the passage and was about to say something about my suspicions of Kato when we heard the sound of footsteps in the hall, and Craig snapped the book shut, returning it hastily to the bookcase. It was Miss Langdale who had made her patient comfortable in bed and now returned to us.

"Who is this Kato?" inquired Craig, voicing what was in my own mind. "What do you know about him?"

"Just a young Japanese from the Mission downtown," replied the nurse, directly. "I don't suppose you know, but Mrs. Wardlaw used to be greatly interested in religious and social work among the Japanese and Chinese; would be yet, but," she added, significantly, "she is not strong enough. They employed him before I came here, about a year ago, I think."

Kennedy nodded, and was about to ask another question, when there was a slight noise out in the hall. Thinking it might be Kato himself, I sprang to the door.

Instead, I encountered a middle-aged man, who drew back in surprise at seeing me, a stranger.

"Oh, good morning, Doctor Aitken!" greeted Miss Langdale, in quite the casual manner of a nurse accustomed to the daily visit at about this hour.

As for Doctor Aitken, he glanced from Leslie, whom he knew, to Kennedy, whom he did not know, with a very surprised look on his face. In fact, I got the impression that after he had been admitted he had paused a moment in the hall to listen to the strange voices in the Wardlaw study.

Leslie nodded to him and introduced us, without quite knowing what to say or do, any more than Doctor Aitken.

"A most incomprehensible case," ventured Aitken to us. "I can't, for the life of me, make it out." The doctor showed his perplexity plainly, whether it was feigned or not.

"I'm afraid she's not quite so well as usual," put in Miss Langdale, speaking to him, but in a manner that indicated that first of all she wished any blame for her patient's condition to attach to us and not to herself.

Doctor Aitken pursed up his lips, bowed excusingly to us, and turned down the hall, followed by the nurse. As they passed on to Mrs. Wardlaw's room, I am sure they whispered about us. I was puzzled by Doctor Aitken. He seemed to be sincere, yet, under the circumstances, I felt that I must be suspicious of everybody and everything.

Alone again for a moment, Kennedy turned his attention to the furniture of the room, and finally paused before a writing-desk in the corner. He tried it. It was not locked and he opened it. Quickly he ran through a pile of papers carefully laid under a paper-weight at the back.

A suppressed exclamation from him called my attention to something that he had discovered. There lay two documents, evidently recently drawn up. As we looked over the first, we saw that it was Doctor Wardlaw's will, in which he had left everything to his wife, although he was not an especially wealthy man. The other was the will of Mrs. Wardlaw.

We devoured it hastily. In substance it was identical with the first, except that at the end she had added two clauses. In the first she had done just as her mother had directed. Twenty-five thousand dollars had been left to Doctor Aitken. I glanced at Kennedy, but he was reading on, taking the second clause. I read also. Fifty thousand dollars was given to endow the New York Japanese Mission.

Immediately the thought of Kato and what Miss Langdale had just told us flashed through my mind.

A second time we heard the nurse's footsteps on the hardwood floor of the hall. Craig closed the desk softly.

"Doctor Aitken is ready to go," she announced. "Is there anything more you wish to ask?"

Kennedy spoke a moment with the doctor as he passed out, but, aside from the information that Mrs. Wardlaw was, in his opinion, growing worse, the conversation added nothing to our meager store of information.

"I suppose you attended Mrs. Marbury?" ventured Kennedy of Miss Langdale, after the doctor had gone.

"Not all the time," she admitted. "Before I came there was another nurse, a Miss Hackstaff."

"What was the matter? Wasn't she competent?"

Miss Langdale avoided the question, as though it were a breach of professional etiquette to cast reflections on another nurse, although whether that was the real reason for her reticence did not appear. Craig seemed to make a mental note of the fact.

"Have you seen anything—er—suspicious about this Kato?" put in Leslie, while Kennedy frowned at the interruption.

Miss Langdale answered quickly, "Nothing."

"Doctor Aitken has never expressed any suspicion?" pursued Leslie.

"Oh no," she returned. "I think I would have known it if he had any. No, I've never heard him even hint at anything." It was evident that she wished us to know that she was in the confidence of the doctor.

"I think we'd better be going," interrupted Kennedy, hastily, not apparently pleased to have Leslie break in in the investigation just at present.

Miss Langdale accompanied us to the door, but before we reached it it was opened from the outside by a man who had once been and yet was handsome, although one could see that he had a certain appearance of having neglected himself.

Leslie nodded and introduced us. It was Doctor Wardlaw.

As I studied his face I could see that, as Leslie had already told us, it plainly bore the stigma of nervousness.

"Has Doctor Aitken been here?" he inquired, quickly, of the nurse. Then, scarcely waiting for her even to nod, he added: "What did he say? Is Mrs. Wardlaw any better?"

Miss Langdale seemed to be endeavoring to make as optimistic a report as the truth permitted, but I fancied Wardlaw read between the lines. As they talked it was evident that there was a sort of restraint between them. I wondered whether Wardlaw might not have some lurking suspicion against Aitken, or some one else. If he had, even in his nervousness he did not betray it.

"I can't tell you how worried I am," he murmured, almost to himself. "What can this thing be?"

He turned to us, and, although he had just been introduced, I am sure that our presence seemed to surprise him, for he went on talking to himself, "Oh yes—let me see—oh yes, friends of Doctor—er—Leslie."

I had been studying him and trying to recall what I had just read of beriberi and polyneuritis. There flashed over my mind the recollection of what had been called Korsakoff's syndrome, in which one of the mental disturbances was the memory of recent events. Did not this, I asked myself, indicate plainly enough that Leslie might be right in his suspicions of beriberi? It was all the more apparent a moment later when, turning to Miss Langdale, Wardlaw seemed almost instantly to forget our presence again. At any rate, his anxiety was easy to see.

After a few minutes' chat during which Craig observed Wardlaw's symptoms, too, we excused ourselves, and the Health Commissioner undertook to conduct us to his office to show us what he had done so far. As for me, I could not get Miss Langdale out of my mind, and especially the mysterious letter to Kennedy. What of it and what of its secret sender?

None of us said much until, half an hour later, in the department laboratory, Leslie began to recapitulate what he had already done in the case.

"You asked whether I had examined the food," he remarked, pausing in a corner before several cages in which were a number of pigeons, separated and carefully tagged. With a wave of his hand at one group of cages he continued: "These fellows I have been feeding exclusively on samples of the various foods which I took from the Wardlaw family when I first went up there. Here, too, are charts showing what I have observed up to date. Over there are the 'controls'—pigeons from the same group which have been fed regularly on the usual diet so that I can check my tests."

Kennedy fell to examining the pigeons carefully as well as the charts and records of feeding and results. None of the birds fed on what had been taken from the apartment looked well, though some were worse than others.

"I want you to observe this fellow," pointed out Leslie at last, singling out one cage. The pigeon in it was a pathetic figure. His eyes seemed dull and glazed. He paid little or no attention to us; even his food and water did not seem to interest him. Instead of strutting about, he seemed to be positively wabbly on his feet. Kennedy examined this one longer and more carefully than any of the rest.

"There are certainly all the symptoms of beriberi, or rather, polyneuritis, in pigeons, with that bird," admitted Craig, finally, looking up at Leslie.

The commissioner seemed to be gratified. "You know," he remarked, "beriberi itself is a common disease in the Orient. There has been a good deal of study of it and the cause is now known to be the lack of something in the food, which in the Orient is mostly rice. Polishing the rice, which removes part of the outer coat, also takes away something that is necessary for life, which scientists now call 'vitamines.'"

"I may take some of these samples to study myself?" interrupted Kennedy, as though the story of vitamines was an old one to him.

"By all means," agreed Leslie.

Craig selected what he wanted, keeping each separate and marked, and excused himself, saying that he had some investigations of his own that he wished to make and would let Leslie know the result as soon as he discovered anything.

Kennedy did not go back directly to the laboratory, however. Instead, he went up-town and, to my surprise, stopped at one of the large breweries. What it was that he was after I could not imagine, but, after a conference with the manager, he obtained several quarts of brewer's yeast, which he had sent directly down to the laboratory.

Impatient though I was at this seeming neglect of the principal figures in the case, I knew, nevertheless, that Kennedy had already schemed out his campaign and that whatever it was he had in mind was of first importance.

Back at last in his own laboratory, Craig set to work on the brewer's yeast, deriving something from it by the plentiful use of a liquid labeled "Lloyd's reagent," a solution of hydrous aluminum silicate.

After working for some time, I saw that he had obtained a solid which he pressed into the form of little whitish tablets. He had by no means finished, but, noticing my impatience, he placed the three or four tablets in a little box and handed them to me.

"You might take these over to Leslie in the department laboratory, Walter," he directed. "Tell him to feed them to that wabbly- looking pigeon over there—and let me know the moment he observes any effect."

Glad of the chance to occupy myself, I hastened on the errand, and even presided over the first feeding of the bird.

When I returned I found that Kennedy had finished his work with the brewer's yeast and was now devoting himself to the study of the various samples of food which he had obtained from Leslie.

He was just finishing a test of the baking-powder when I entered, and his face showed plainly that he was puzzled by something that he had discovered.

"What is it?" I asked. "Have you found out anything?"

"This seems to be almost plain sodium carbonate," he replied, mechanically.

"And that indicates?" I prompted.

"Perhaps nothing, in itself," he went on, less abstractedly. "But the use of sodium carbonate and other things which I have discovered in other samples disengages carbon dioxide at the temperature of baking and cooking. If you'll look in that public- health report on my desk you'll see how the latest investigations have shown that bicarbonate of soda and a whole list of other things which liberate carbon dioxide destroy the vitamines Leslie was talking about. In other words, taken altogether I should almost say there was evidence that a concerted effort was being made to affect the food—a result analogous to that of using polished rice as a staple diet—and producing beriberi, or, perhaps more accurately, polyneuritis. I can be sure of nothing yet, but—it's worth following up."

"Then you think Kato—"

"Not too fast," cautioned Craig. "Remember, others had access to the kitchen, too."

In spite of his hesitancy, I could think only of the two paragraphs we had read in Mrs. Wardlaw's will, and especially of the last. Might not Kato have been forced or enticed into a scheme that promised a safe return and practically no chance of discovery? What gruesome mystery had been unveiled by the anonymous letter which had first excited our curiosity?

It was late in the afternoon that Commissioner Leslie called us up, much excited, to inform us that the drooping pigeon was already pecking at food and beginning to show some interest in life. Kennedy seemed greatly gratified as he hung up the receiver.

"Almost dinner-time," he commented, with a glance at his watch. "I think we'll make another hurried visit to the Wardlaw apartment."

We had no trouble getting in, although as outsiders we were more tolerated than welcome. Our excuse was that Kennedy had some more questions which we wished to ask Miss Langdale.

While we waited for her we sat, not in the study, but in the parlor. The folding-doors into the dining-room were closed, but across the hall we could tell by the sound when Kato was in the kitchen and when he crossed the hall.

Once I heard him in the dining-room. Before I knew it Kennedy had hastily tiptoed across the hall and into the kitchen. He was gone only a couple of minutes, but it was long enough to place in the food that was being prepared, and in some unprepared, either the tablets he had made or a powder he had derived from them crushed up. When he returned I saw from his manner that the real purpose of the visit had been accomplished, although when Miss Langdale appeared he went through the form of questioning her, mostly on Mrs. Marbury's sickness and death. He did not learn anything that appeared to be important, but at least he covered up the reason for his visit. Outside the apartment, Kennedy paused a moment. "There's nothing to do now but await developments," he meditated. "Meanwhile, there is no use for us to double up our time together. I have decided to watch Kato to-night. Suppose you shadow Doctor Aitken. Perhaps we may get a line on something that way."

The plan seemed admirable to me. In fact, I had been longing for some action of the sort all the afternoon, while Kennedy had been engaged in the studies which he evidently deemed more important.

Accordingly, after dinner, we separated, Kennedy going back to the Forum Apartments to wait until Kato left for the night, while I walked farther up the Drive to the address given in the directory as that of Doctor Aitken.

It happened to be the time when the doctor had his office hours for patients, so that I was sure at least that he was at home when I took my station just down the street, carefully scrutinizing every one who entered and left his house.

Nothing happened, however, until the end of the hour during which he received office calls. As I glanced down the street I was glad that I had taken an inconspicuous post, for I could see Miss Langdale approaching. She was not in her nurse's uniform, but seemed to be off duty for an hour or two, and I must confess she was a striking figure, even in that neighborhood which was noted for its pretty and daintily gowned girls. Almost before I knew it she had entered the English-basement entrance of Doctor Aitken's.

I thought rapidly. What could be the purpose of her visit? Above all, how was I, on the outside, to find out? I walked down past the house. But that did no good. In a quandary, I stopped. Hesitation would get me nothing. Suddenly an idea flashed through my mind. I turned in and rang the bell.

"It's past the doctor's office hours," informed a servant who opened the door. "He sees no one after hours."

"But," I lied, "I have an appointment. Don't disturb him. I can wait."

The waiting-room was empty, I had seen, and I was determined to get in at any cost. Reluctantly the servant admitted me.

For several moments I sat quietly alone, fearful that the doctor might open the double doors of his office and discover me. But nothing happened and I grew bolder. Carefully I tiptoed to the door. It was of solid oak and practically impervious to sound. The doors fitted closely, too. Still, by applying my ear, I could make out the sound of voices on the other side. I strained my ears both to catch a word now and then and to be sure that I might hear the approach of anybody outside.

Was Aitken suspiciously interested in the pretty nurse—or was she suspiciously interested in him?

Suddenly their voices became a trifle more distinct. "Then you think Doctor Wardlaw has it, too?" I heard her ask. I did not catch the exact reply, but it was in the affirmative.

They were approaching the door. In a moment it would be opened. I waited to hear no more, but seized my hat and dashed for the entrance from the street just in time to escape observation. Miss Langdale came out shortly, the doctor accompanying her to the door, and I followed her back to the Forum.

What I had heard only added to the puzzle. Why her anxiety to know whether Wardlaw himself was affected? Why Aitken's solicitude in asserting that he was? Were they working together, or were they really opposed? Which might be using the other?

My queries still unanswered, I returned to Aitken's and waited about some time, but nothing happened, and finally I went on to our own apartment.

It was very late when Craig came in, but I was still awake and waiting for him. Before I could ask him a question he was drawing from me what I had observed, listening attentively. Evidently he considered it of great importance, though no remark of his betrayed what interpretation he put on the episode.

"Have you found anything?" I managed to ask, finally.

"Yes, indeed," he nodded, thoughtfully. "I shadowed Kato from the Forum. It must have been before Miss Langdale came out that he left. He lives down-town in a tenement-house. There's something queer about that Jap."

"I think there is," I agreed. "I don't like his looks."

"But it wasn't he who interested me so much to-night," Craig went on, ignoring my remark, "as a woman."

"A woman?" I queried, in surprise. "A Jap, too?"

"No, a white woman, rather good-looking, too, with dark hair and eyes. She seemed to be waiting for him. Afterward I made inquiries. She has been seen about there before."

"Who was she?" I asked, fancying perhaps Miss Langdale had made another visit while she was out, although from the time it did not seem possible.

"I followed her to her house. Her name is Hackstaff—"

"The first trained nurse!" I exclaimed.

"Miss Hackstaff is an enigma," confessed Kennedy. "At first I thought that perhaps she might be one of those women whom the Oriental type fascinated, that she and Kato might be plotting. Then I have considered that perhaps her visits to Kato may be merely to get information—that she may have an ax to grind. Both Kato and she will bear watching, and I have made arrangements to have it done. I've called on that young detective, Chase, whom I've often used for the routine work of shadowing. There's nothing more that we can do now until to-morrow, so we might as well turn in."

Early the next day Kennedy was again at work, both in his own laboratory and in that of the Health Department, making further studies of the food and the effect it had on the pigeons, as well as observing what changes were produced by the white tablets he had extracted from the yeast.

It was early in the forenoon when the buzzer on the laboratory door sounded and I opened the door to admit Chase in a high state of excitement.

"What has happened?" asked Craig, eagerly.

"Many things," reported the young detective, breathlessly. "To begin with, I followed Miss Hackstaff from her apartment this morning. She seemed to be worked up over something—perhaps had had a sleepless night. As nearly as I could make out she was going about aimlessly. Finally, however, I found that she was getting into the neighborhood of Doctor Aitken and of the Forum. Well, when we got to the Forum she stopped and waited in front of it— oh, I should say almost half an hour. I couldn't make out what it was she wanted, but at last I found out."

He paused a moment, then raced on, without urging. "Miss Langdale came out—and you should have seen the Hackstaff woman go for her." He drew in his breath sharply at the reminiscence. "I thought there was going to be a murder done—on Riverside Drive. Miss Langdale screamed and ran back into the apartment. There was a good deal of confusion. The hall-boys came to the rescue. In the excitement, I managed to slip into the elevator with her. No one seemed to think it strange then that an outsider should be interested. I went up with her—saw Wardlaw, as she poured out the story. He's a queer one. Is he RIGHT?" "Why?" asked Craig, indulgently.

"He seems so nervous; things upset him so easily. Yet, after we had taken care of Miss Langdale and matters had quieted down, I thought I might get some idea of the cause of the fracas and asked him if he knew of any reason. Why, he looked at me kind of blankly, and I swear he acted as though he had almost forgotten it already. I tell you, he's not RIGHT."

Remembering our own experience, I glanced significantly at Craig. "Korsakoff's syndrome?" I queried, laconically. "Another example of a mind confused even on recent events?"

Kennedy, however, was more interested in Chase. "What did Miss Hackstaff do?" he asked.

"I don't know. I missed her. When I got out again she was gone."

"Pick her up again," directed Craig. "Perhaps you'll get her at her place. And see, this time, if you can get what I asked you."

"I'll try," returned Chase, much pleased at the words of commendation which Craig added as he left us again.

On what errand Chase had gone I could not guess, except that it had something to do with this strange woman who had so unexpectedly entered the case. Nor was Craig any more communicative. There were evidently many problems which only events could clear up even in his mind. Though he did not say anything, I knew that he was as impatient as I was, and as Leslie, too, who called up once or twice to learn whether he had discovered anything. There was nothing to do but wait.

It was early in the afternoon that the telephone rang and I answered it. It was Chase calling Kennedy. I heard only half the conversation and there was not much of that, but I knew that something was about to happen. Craig hastily summoned a cab, then in rapid succession called up Doctor Aitken and Leslie, for whom we stopped as our driver shot us over to the Forum Apartments.

There was no ceremony or unnecessary explanation about our presence, as Kennedy entered and directed Miss Langdale to bring her patients into the little office-study of Doctor Wardlaw.

Miss Langdale obeyed reluctantly. When she returned I felt that it was appreciable that a change had taken place. Mrs. Wardlaw, at least, was improved. She was still ill, but she seemed to take a more lively interest in what was going on about her. As for Doctor Wardlaw, however, I could not see that there had been any improvement in him. His nervousness had not abated. Kato, whom Kennedy summoned at the same time, preserved his usual imperturbable exterior. Miss Langdale, in spite of the incident of the morning, was quite as solicitous as ever of her charges.

We had not long to wait for Doctor Aitken. He arrived, inquiring anxiously what had happened, although Kennedy gave none of us any satisfaction immediately as to the cause of his quick action. Aitken fidgeted uneasily, glancing from Kennedy to Leslie, then to Miss Langdale, and back to Kennedy, without reading any explanation in the faces. I knew that Craig was secretly taking his time both for its effect on those present and to give Chase a chance.

"Our poisons and our drugs," he began, leisurely, at length, "are in many instances the close relatives of harmless compounds that represent the intermediate steps in the daily process of metabolism. There is much that I might say about protein poisons. However, that is not exactly what I want to talk about—at least first."

He stopped to make sure that he had the attention of us all. As a matter of fact, his manner was such that he attracted even the vagrant interest of the Wardlaws.

"I do not know how much of his suspicions Commissioner Leslie has communicated to you," he resumed, "but I believe that you have all heard of the disease beriberi so common in the Far East and known to the Japanese as kakke. It is a form of polyneuritis and, as you doubtless know, is now known to be caused, at least in the Orient, by the removal of the pericarp in the polishing of rice. Our milling of flour is, in a minor degree, analogous. To be brief, the disease arises from the lack in diet of certain substances or bodies which modern scientists call vitamines. Small quantities of these vital principles are absolutely essential to normal growth and health and even to life itself. They are nitrogenous compounds and their absence gives rise to a class of serious disorders in which the muscles surrender their store of nitrogen first. The nerves seems to be the preferred creditors, so to speak. They are affected only after the muscles begin to waste. It is an abstruse subject and it is not necessary for me to go deeper into it now."

I controlled my own interest in order to watch those about me. Kato, for one, was listening attentively, I saw.

"In my studies of the diet of this household," continued Kennedy, "I have found that substances have been used in preparing food which kill vitamines. In short, the food has been denatured. Valuable elements, necessary elements, have been taken away."

"I, sir, not always in kitchen, sir," interrupted Kato, still deferential. "I not always know—"

With a peremptory wave of his hand Kennedy silenced the Jap.

"It has long been a question," he hurried on, "whether these vitamines are tangible bodies or just special arrangements of molecules. Recently government investigators have discovered that they are bodies that can be isolated by a special process from the filtrate of brewer's yeast by Lloyd's reagent. Five grams of this"—he held up some of the tablets he had made—"for a sixty- kilogram person each day are sufficient. Unknown to you, I have introduced some of this substance into the food already deficient in vitamines. I fancy that even now I can detect a change," he nodded toward Mrs. Wardlaw.

There was a murmur of surprise in the room, but before Craig could continue further the door opened and Mrs. Wardlaw uttered a nervous exclamation. There stood Chase with a woman. I recognized her immediately from Kennedy's description as Miss Hackstaff.

Chase walked deliberately over to Kennedy and handed him something, while the nurse glanced calmly, almost with pity, at Mrs. Wardlaw, ignoring Wardlaw, then fixing her gaze venomously on Miss Langdale. Recalling the incident of the morning, I was ready to prevent, if necessary, a repetition now. Neither moved. But it was a thrilling, if silent, drama as the two women glared at each other.

Kennedy was hastily comparing the anonymous note he had received with something Chase had brought.

"Some one," he shot out, suddenly, looking up and facing us, "has, as I have intimated, been removing or destroying the vital principle in the food—these vitamines. Clearly the purpose was to make this case look like an epidemic of beriberi, polyneuritis. That part has been clear to me for some time. It has been the source of this devilish plot which has been obscure. Just a moment, Kato, I will do the talking. My detective, Chase, has been doing some shadowing for me, as well as some turning over of past history. He has found a woman, a nurse, more than a nurse, a secret lover, cast off in favor of another. Miss Hackstaff—you wrote that letter—it is your hand—for revenge—on Miss Langdale and—"

"You shan't have him!" almost hissed Helen Hackstaff. "If I cannot—no one shall!"

Natalie Langdale faced her, defiant. "You are a jealous, suspicious person," she cried. "Doctor Aitken knows—"

"One moment," interrupted Craig. "Mrs. Marbury is gone. Mrs. Wardlaw is weakened. Yet all who are affected with nerve troubles are not necessarily suffering from polyneuritis. Some one here has been dilettanting with death. It is of no use," he thundered, turning suddenly on a cowering figure. "You stood to win most, with the money and your unholy love. But Miss Hackstaff, cast off, has proved your Nemesis. Your nervousness is the nervousness not of polyneuritis, but of guilt, Doctor Wardlaw!"



IX

THE RUBBER DAGGER

"Hypnotism can't begin to accomplish what Karatoff claims. He's a fake, Kennedy, a fake."

Professor Leslie Gaines of the Department of Experimental Psychology at the university paced excitedly up and down Craig's laboratory.

"There have been complaints to the County Medical Society," he went on, without stopping, "and they have taken the case up and arranged a demonstration for this afternoon. I've been delegated to attend it and report."

I fancied from his tone and manner that there was just a bit more than professional excitement involved. We did not know Gaines intimately, though of course Kennedy knew of him and he of Kennedy. Some years before, I recollected, he had married Miss Edith Ashmore, whose family was quite prominent socially, and the marriage had attracted a great deal of attention at the time, for she had been a student in one of his courses when he was only an assistant professor.

"Who is Karatoff, anyhow?" asked Kennedy. "What is known about him?"

"Dr. Galen Karatoff—a Russian, I believe," returned Gaines. "He claims to be able to treat disease by hypnotism-suggestion, he calls it, though it is really something more than that. As nearly as I can make out it must almost amount to thought transference, telepathy, or some such thing. Oh, he has a large following; in fact, some very well-known people in the smart set are going to him. Why," he added, facing us, "Edith—my wife—has become interested in his hypnotic clinics, as he calls them. I tell her it is more than half sham, but she won't believe it."

Gaines paused and it was evident that he hesitated over asking something.

"When is the demonstration?" inquired Kennedy, with unconcealed interest.

The professor looked at his watch. "I'm going over there now; in fact, I'm just a bit late—only, I happened to think of you and it occurred to me that perhaps if you could add something to my report it might carry weight. Would you like to come with me? Really, I should think that it might interest you."

So far Kennedy had said little besides asking a question or two. I knew the symptoms. Gaines need not have hesitated or urged him. It was just the thing that appealed to him.

"How did Mrs. Gaines become interested in the thing?" queried Craig, a moment later, outside, as we climbed into the car with the professor.

"Through an acquaintance who introduced her to Karatoff and the rest. Carita Belleville, the dancer, you know?"

Kennedy glanced at me and I nodded that I had heard of her. It was only a few nights before that I had seen Carita at one of the midnight revues, doing a dance which was described as the "hypnotic whirl," a wild abandon of grace and motion. Carita Belleville had burst like a meteor on the sky of the "Great White Way," blazing a gorgeous trail among the fixed stars of that gay firmament. She had even been "taken up" by society, or at least a certain coterie of it, had become much sought after to do exhibition dancing at social affairs, and now was well known in the amusement notes of the newspapers and at the fashionable restaurants. She had hosts of admirers and I had no doubt that Mrs. Gaines might well have fallen under the spell of her popularity.

"What is Miss Belleville's interest in Karatoff?" pursued Craig, keenly.

Gaines shrugged his shoulders. "Notoriety, perhaps," he replied. "It is a peculiar group that Karatoff has gathered about him, they tell me."

There was something unsatisfactory about the answer and I imagined that Gaines meant purposely to leave it so as not to prejudice the case. Somehow, I felt that there must be something risque in the doings of Karatoff and his "patients." At any rate, it was only natural with anything that Carita Belleville was likely to be concerned with.

There was little time for further questions, for our destination was not far down the Drive from the university, and the car pulled up before one of the new handsome and ornate "studio apartments" up-town.

We followed Gaines into the building, and the hall-boy directed us to a suite on the first floor.

A moment later we were admitted by Karatoff himself to what had become known as his "hypnotic clinic," really a most artistically furnished studio.

Karatoff himself was a tall, dark-haired fellow, bearded, somewhat sallow. Every feature of his remarkable face, however, was subordinate to a pair of wonderful, deep-set, piercing eyes. Even as he spoke, greeting Gaines on the rather ticklish mission he had come, and accepting us with a quick glance and nod, we could see instantly that he was, indeed, a fascinating fellow, every inch a mystic.

His clinic, or, as I have said, studio, carried out well the impression of mysticism that one derived from the strange personality who presided over it. There were only two or three rooms in the apartment, one being the large room down the end of a very short hall to which he conducted us. It was darkened, necessarily, since it was on the first floor of the tall building, and the air seemed to be heavy with odors that suggested the Orient. Altogether there was a cultivated dreaminess about it that was no less exotic because studied. Doctor Karatoff paused at the door to introduce us, and we could see that we were undergoing a close scrutiny from the party who were assembled there.

On a quaint stand tea was brewing and the whole assemblage had an atmosphere of bohemian camaraderie which, with the professions of Karatoff, promised well that Kennedy was not wasting time.

I watched particularly the exchange of greetings between Professor Gaines and Edith Gaines, who was already there. Neither of them seemed to be perfectly at ease, though they betrayed as little as they could. However, one could not help noticing that each was watching the other, naturally.

Edith Gaines was a pretty little woman, petite, light of hair, dainty, the very type of woman who craved for and thrived on attention. Here at least there seemed to be no lack of it. There was only one other woman in the room who attracted the men equally, Carita Belleville herself. Carita was indeed a stunning woman, tall, slender, dark, with a wonderful pair of magnetic eyes.

As I watched, I could see that both women were quite friendly with Doctor Karatoff—perhaps even rivals for his attentions. I saw Gaines watching Carita attentively, never in the mean time failing for long to lose sight of Mrs. Gaines. Was he trying to estimate the relative popularity of the two in this strange group? If so, I failed to see any approval of either.

Introductions were now coming so fast that neither Kennedy nor I had much opportunity except for the most cursory observation of the people. Among the men, however, I noticed two especially who proved worth observation. One was Armand Marchant, well known as a broker, not so much for his professional doings as for his other activities. Though successful, he was better known as one of those who desert Wall Street promptly at the hour of closing, to be found late in the afternoon at the tea dances up-town.

Another was Cyril Errol, a man of leisure, well known also in the club world. He had inherited an estate, small, perhaps, but ample to allow him to maintain appearances. Errol impressed you as being one to whom the good things of the world appealed mightily, a hedonist, and, withal, very much attracted to and by the ladies.

It was fortunate that the serving of tea enabled us to look about and get our bearings. In spite of the suppressed excitement and obvious restraint of the occasion, we were able to learn much over the tea-cups.

Errol seemed to vibrate between the group about Mrs. Gaines and that about Miss Belleville, welcome wherever he went, for he was what men commonly call a "good mixer." Marchant, on the other hand, was almost always to be found not far from Edith Gaines. Perhaps it was the more brilliant conversation that attracted him, for it ran on many subjects, but it was difficult to explain it so to my satisfaction. All of which I saw Gaines duly noting, not for the report he had to make to the Medical Society, but for his own information. In fact, it was difficult to tell the precise degree of disapproval with which he regarded Karatoff, Errol, and Marchant, in turn, as he noted the intimacy of Edith Gaines with them. I wished that we might observe them all when they did not know it, for I could not determine whether she was taking pleasure in piquing the professor or whether she was holding her admirers in leash in his presence. At any rate, I felt I need lay no claim to clairvoyance to predict the nature of the report that Gaines would prepare.

The conversation was at its height when Karatoff detached himself from one of the groups and took a position in a corner of the room, alone. Not a word was said by him, yet as if by magic the buzz of conversation ceased. Karatoff looked about as though proud of the power of even his silence. Whatever might be said of the man, at least his very presence seemed to command respect from his followers.

I had expected that he would make some reference to Gaines and ourselves and the purpose of the meeting, but he avoided the subject and, instead, chose to leap right into the middle of things.

"So that there can be no question about what I am able to do," he began, "I wish each of you to write on a piece of paper what you would like to have me cause any one to do or say under hypnotism. You will please fold the paper tightly, covering the writing. I will read the paper to myself, still folded up, will hypnotize the subject, and will make the subject do whatever is desired. That will be preliminary to what I have to say later about my powers in hypnotic therapeutics."

Pieces of paper and little lead-pencils were distributed by an attendant and in the rustling silence that followed each cudgeled his brain for something that would put to the test the powers of Karatoff.

Thinking, I looked about the room. Near the speaker stood a table on which lay a curious collection of games and books, musical instruments, and other things that might suggest actions to be performed in the test. My eye wandered to a phonograph standing next the table. Somehow, I could not get Mrs. Gaines and Carita Belleville out of my head.

Slowly I wrote, "Have Mrs. Gaines pick out a record, play it on the phonograph, then let her do as she pleases."

Some moments elapsed while the others wrote. Apparently they were trying to devise methods of testing Doctor Karatoff's mettle. Then the papers were collected and deposited on the table beside him.

Apparently at random Karatoff picked out one of the folded papers, then, seemingly without looking at it and certainly without unfolding it, as far as I could determine, he held it up to his forehead.

It was an old trick, I knew. Perhaps he had palmed a sponge wet with alcohol or some other liquid, had brushed it over the paper, making the writing visible through it, and drying out rapidly so as to leave the paper opaque again long before any of us saw it a second time. Or was he really exercising some occult power? At any rate, he read it, or pretended to read it, at least.

"I am asked to hypnotize Mrs. Gaines," he announced, dropping the paper unconcernedly on the table beside the other pile, as though this were mere child's play for his powers. It was something of a shock to realize that it was my paper he had chanced to pick up first, and I leaned forward eagerly, watching.

Mrs. Gaines rose and every eye was riveted on her as Karatoff placed her in an easy-chair before him. There was an expectant silence, as Karatoff moved the chair so that she could concentrate her attention only on a bright silver globe suspended from the ceiling. The half-light, the heavy atmosphere, the quiet, assured manner of the chief actor in the scene, all combined to make hypnotization as nearly possible as circumstances could. Karatoff moved before her, passing his hands with a peculiar motion before her eyes. It seemed an incredibly short time in which Edith Gaines yielded to the strange force which fascinated the group.

"Quite susceptible," murmured Kennedy, beside me, engrossed in the operation.

"It is my test," I whispered back, and he nodded.

Slowly Edith Gaines rose from the chair, faced us with unseeing eyes, except as Karatoff directed. Karatoff himself was a study. It seemed as if he had focused every ounce of his faculties on the accomplishment of the task in hand. Slowly still the woman moved, as if in a dream walk, over toward the phonograph, reached into the cabinet beneath it and drew forth a book of records. Karatoff faced us, as if to assure us that at that point he had resigned his control and was now letting her act for her subconscious self.

Her fingers passed over page after page until finally she stopped, drew forth the record, placed it on the machine, wound it, then placed the record on the revolving disk.

My first surprise was quickly changed to gratification. She had picked out the music to the "Hypnotic Whirl." I bent forward, more intent. What would she do next?

As she turned I could see, even in the dim light, a heightened color in her cheeks, as though the excitement of the catchy music had infected her. A moment later she was executing, and very creditably, too, an imitation of Carita herself in the Revue. What did it mean? Was it that consciously or unconsciously she was taking the slender dancer as her model? The skill and knowledge that she put into the dance showed plainly.

Next to Kennedy, I saw Gaines leaning far forward, looking now at his wife, now at the little group. I followed his eyes. To my surprise, I saw Marchant, his gaze riveted on Edith Gaines as if she had been the star performer in a play. Evidently my chance request to Karatoff had been builded better than I knew. I ran my gaze over the others. Errol was no less engrossed than Marchant. Quickly I glanced at Carita, wondering whether she might be gratified by the performance of a pupil. Whether it was natural grace or real hypnotism in the "Hypnotic Whirl," I was surprised to see on Carita's face something that looked strangely akin to jealousy. It was as though some other woman had usurped her prerogative. She leaned over to speak to Errol with the easy familiarity of an old admirer. I could not hear what was said and perhaps it was inconsequential. In fact, it must have been the very inconsequentiality of his reply that piqued her. He glanced at Marchant a moment, as if she had said something about him, then back at Edith Gaines. On his part, Professor Gaines was growing more and more furious.

I had just about decided that the little drama in the audience was of far more importance and interest than even the dance, when the music ceased. Karatoff approached, took Mrs. Gaines by the hand, led her back to the chair, and, at a word, she regained her normal consciousness. As she rose, still in a daze it seemed, it was quite evident that she had no waking realization of what had happened, for she walked back and sat down beside her husband, quite as though nothing had happened.

As for me, I could not help wondering what had actually happened. What did it all mean? Had Mrs. Gaines expressed her own self—or was it Karatoff—or Marchant—or Errol? What was the part played by Carita Belleville? Gaines did not betray anything to her, but their mutual attitude was eloquent. There was something of which he disapproved and she knew it, some lack of harmony. What was the cause?

As for Karatoff's exhibition, it was all truly remarkable, whether in his therapeutics the man was a faker or not.

Karatoff seemed to realize that he had made a hit. Without giving any one a chance to question him, he reached down quickly and picked up another of the papers, repeating the process through which he had gone before.

"Mr. Errol," he summoned, placing the second folded paper on the table with the first.

Errol rose and went forward and Karatoff placed him in the chair as he had Mrs. Gaines. There seemed to be no hesitation, at least on the part of Karatoff's followers, to being hypnotized.

Whatever it was written on the paper, the writer had evidently not trusted to chance, as I had, but had told specifically what to do.

At the mute bidding of Karatoff Errol rose. We watched breathlessly. Deliberately he walked across the room to the table, and, to the astonishment of all save one, picked up a rubber dagger, one of those with which children play, which was lying in the miscellaneous pile on the table. I had not noticed it, but some one's keen eye had, and evidently it had suggested a melodramatic request.

Quickly Errol turned. If he had been a motion-picture actor, he could not have portrayed better the similitude of hate that was written on his face. A few strides and he had advanced toward our little audience, now keyed up to the highest pitch of excitement by the extraordinary exhibition.

"Of course," remarked Karatoff, as at a word Errol paused, still poising the dagger, "you know that under hypnotism in the psychological laboratory a patient has often struck at his 'enemy' with a rubber dagger, going through all the motions of real passion. Now!"

No word was said by Karatoff to indicate to Errol what it was that he was to do. But a gasp went up from some one as he took another step and it was evident that it was Marchant whom he had singled out. For just a moment Errol poised the rubber dagger over his "victim," as if gloating. It was dramatic, realistic. As Errol paused, Marchant smiled at the rest of us, a sickly smile, I thought, as though he would have said that the play was being carried too far.

Never for a moment did Errol take from him the menacing look. It was only a moment in the play, yet it was so unexpected that it seemed ages. Then, swiftly, down came the dagger on Marchant's left side just over the breast, the rubber point bending pliantly as it descended.

A sharp cry escaped Marchant. I looked quickly. He had fallen forward, face down, on the floor.

Edith Gaines screamed as we rushed to Marchant and turned him over. For the moment, as Kennedy, Karatoff, and Gaines bent over him and endeavored to loosen his collar and apply a restorative, consternation reigned in the little circle. I bent over, too, and looked first at Marchant's flushed face, then at Kennedy. Marchant was dead!

There was not a mark on him, apparently. Only a moment before he had been one of us. We could look at one another only in amazement, tinged with fear. Killed by a rubber dagger? Was it possible?

"Call an ambulance—quick!" directed Kennedy to me, though I knew that he knew it was of no use except as a matter of form.

We stood about the prostrate form, stunned. In a few moments the police would be there. Instinctively we looked at Karatoff. Plainly he was nervous and overwrought now. His voice shook as he brought Errol out of the trance, and Errol, dazed, uncomprehending, struggled to take in the horribly unreal tragedy which greeted his return to consciousness.

"It—it was an accident," muttered Karatoff, eagerly trying to justify himself, though trembling for once in his life. "Arteriosclerosis, perhaps, hardening of the arteries, some weakness of the heart. I never—"

He cut the words short as Edith Gaines reeled and fell into her husband's arms. She seemed completely prostrated by the shock. Or was it weakness following the high mental tension of her own hypnotization? Together we endeavored to revive her, waiting for the first flutter of her eyelids, which seemed an interminable time.

Errol in the mean time was pacing the floor like one in a dream. Events had followed one another so fast in the confusion that I had only an unrelated series of impressions. It was not until a moment later that I realized the full import of the affair, when I saw Kennedy standing near the table in the position Karatoff had assumed, a strange look of perplexity on his face. Slowly I realized what was the cause. The papers on which were written the requests for the exhibitions of Karatoff's skill were gone!

Whatever was done must be done quickly, and Kennedy looked about with a glance that missed nothing. Before I could say a word about the papers he had crossed the room to where Marchant had been standing in the little group about Edith Gaines as we entered. On a side-table stood the teacup from which he had been sipping. With his back to the rest, Kennedy drew from his breast pocket a little emergency case he carried containing a few thin miniature glass tubes. Quickly he poured the few drops of the dregs of the tea into one of the tubes, then into others tea from the other cups.

Again he looked at the face of Marchant as though trying to read in the horrified smile that had petrified on it some mysterious secret hidden underneath. Slowly the question was shaping in my mind, was it, as Karatoff would have us believe, an accident?

The clang of a bell outside threw us all into worse confusion, and a moment later, almost together, a white-coated surgeon and a blue-coated policeman burst into the room. It seemed almost no time, in the swirl of events, before the policeman was joined by a detective assigned by the Central Office to that district.

"Well, doctor," demanded the detective as he entered, "what's the verdict?"

"Arteriosclerosis, I think," replied the young surgeon. "They tell me there was some kind of hypnotic seance going on. One of them named Errol struck at him with a rubber dagger, and—"

"Get out!" scoffed the Central Office man. "Killed by a rubber dagger! Say, what do you think we are? What did you find when you entered, sergeant?"

The policeman handed the detective the rubber dagger which he had picked up, forgotten, on the floor where Errol had dropped it when he came out from the hypnotization.

The detective took it gingerly and suspiciously, with a growl. "I'll have the point of this analyzed. It may be—well—we won't say what may be. But I can tell you what is. You, Doctor Karatoff, or whatever your name is, and you, Mr. Errol, are under arrest. It's a good deal easier to take you now than it will be later. Then if you can get a judge to release you, we'll at least know where you are."

"This is outrageous, preposterous!" stormed Karatoff.

"Can't help it," returned the officer, coolly.

"Why," exclaimed Carita Belleville, excitedly projecting herself before the two prisoners, "it's ridiculous! Even the ambulance surgeon says it was arteriosclerosis, an accident. I—"

"Very well, madam," calmed the sergeant. "So much the better. They'll get out of our hands that much quicker. Just at present it is my duty."

Errol was standing silent, his eyes averted from the hideous form on the floor, not by word or action betraying a feeling. The police moved to the door.

Weak and trembling still from the triple shock she had received, Edith Gaines leaned heavily on the arm of her husband, but it was, as nearly as I could make out, only for physical support.

"I told you, Edith, it was a dangerous business," I heard him mutter. "Only I never contemplated that they'd carry it this far. Now you see what such foolishness can lead to."

Weak though she was, she drew away and flashed a glance at him, resenting his man's "I-told-you-so" manner. The last I saw of them in the confusion was as they drove off in the car, still unreconciled.

Kennedy seemed well contented, for the present at least, to allow the police a free hand with Errol and Karatoff. As for me, Mrs. Gaines and Carita Belleville presented a perplexing problem, but I said nothing, for he was hurrying back now to his laboratory.

At once he drew forth the little tube containing the few drops of tea and emptied a drop or two into a beaker of freshly distilled water as carefully as if the tea had been some elixir of life. As he was examining the contents of the beaker his face clouded with thought.

"Do you find anything?" I asked, eagerly.

Kennedy shook his head. "There's something wrong," he hazarded. "Perhaps it's only fancy, but I am sure that there is something with a slight odor in the tea, something tea-like, but with a more bitter taste, something that would be nauseous if not concealed in the tea. There's more than tannin and sugar here."

"Then you think that some one present placed something in the tea?" I inquired, shuddering at the thought that we had run some unknown danger.

"I can't just say, without further investigation of this and the other samples I took."

"Still, you have eliminated that ridiculous dagger theory," I ventured.

"The police can never appreciate the part it played," Craig answered, non-committally, laying out various chemicals preparatory to his exhaustive analysis. "I began to suspect something the moment I noticed that those notes which we all wrote were gone. When we find out about this tea we may find who took them. Perhaps the mystery is not such a mystery after all, then."

There seemed to be nothing that I could do, in the mean time, except to refrain from hindering Kennedy in his investigations, and I decided to leave him at the laboratory while I devoted my time to watching what the police might by chance turn up, even if they should prove to be working on the wrong angle of the case.

I soon found that they were showing energy, if nothing else. Although it was so soon after the death of Marchant, they had determined that there could not have been anything but rubber on the end of the toy dagger which had excited the doubts of the detective.

As for the autopsy that was performed on Marchant, it did, indeed, show that he was suffering from hardening of the arteries, due to his manner of living, as Karatoff had asserted. Indeed, the police succeeded in showing that it was just for that trouble that Marchant was going to Karatoff, which, to my mind, seemed quite sufficient to establish the therapeutic hypnotist as all that Gaines had accused him of being. Even to my lay mind the treatment of arteriosclerosis by mental healing seemed, to say the least, incongruous.

Yet the evidence against Karatoff and Errol was so flimsy that they had little trouble in getting released on bail, though, of course, it was fixed very high.

My own inquiries among the other reporters on the Star who might know something offered a more promising lead. I soon found that Errol had none too savory a reputation. His manner of life had added nothing to his slender means, and there was a general impression among his fellow club-members that unfortunate investments had made serious inroads into the principal of his fortune. Still, I hesitated to form even an opinion on gossip.

Quite unsatisfied with the result of my investigation, I could not restrain my impatience to get back to the laboratory to find out whether Kennedy had made any progress in his tests of the tea.

"If you had been five minutes earlier," he greeted me, "you would have been surprised to find a visitor."

"A visitor?" I repeated. "Who?"

"Carita Belleville," he replied, enjoying my incredulity.

"What could she want?" I asked, at length.

"That's what I've been wondering," he agreed "Her excuse was plausible. She said that she had just heard why I had come with Gaines. I suppose it was half an hour that she spent endeavoring to convince me that Karatoff and Errol could not possibly have had any other connection than accidental with the death of Marchant."

"Could it have been a word for them and half an hour for herself?" I queried, mystified.

Kennedy shrugged. "I can't say. At any rate, I must see both Karatoff and Errol, now that they are out. Perhaps they did send her, thinking I might fall for her. She hinted pretty broadly at using my influence with Gaines on his report. Then, again, she may simply have been wondering how she herself stood."

"Have you found anything?" I asked, noticing that his laboratory table was piled high with its usual paraphernalia.

"Yes," he replied, laconically, taking a bottle of concentrated sulphuric acid and pouring a few drops in a beaker of slightly tinged water.

The water turned slowly to a beautiful green. No sooner was the reaction complete than he took some bromine and added it. Slowly again the water changed, this time from the green to a peculiar violet red. Adding more water restored the green color.

"That's the Grandeau test," he nodded, with satisfaction. "I've tried the physiological test, too, with frogs from the biological department, and it shows the effect on the heart that I—"

"What shows the effect?" I interrupted, somewhat impatiently.

"Oh, to be sure," he smiled. "I forgot I hadn't told you what I suspected. Why, digitalis—foxglove, you know. I suppose it never occurred to the police that the rubber dagger might have covered up a peculiar poisoning? Well, if they'll take the contents of the stomach, in alcohol, with a little water acidulated, strain off the filtrate and try it on a dog, they will see that its effect is the effect of digitalis. Digitalis is an accumulative poison and a powerful stimulant of arterial walls, by experimental evidence an ideal drug for the purpose of increasing blood pressure. Don't you see it?" he added, excitedly. "The rubber dagger was only a means to an end. Some one who knew the weakness of Marchant first placed digitalis in his tea. That was possible because of the taste of the tea. Then, in the excitement of the act pantomimed by Errol, Marchant's disease carried him off, exactly as was to be expected under the circumstances. It was clever, diabolically clever. Whoever did it destroyed the note in which the act was suggested and counted that no one would ever stop to search for a poison in the tangle of events."

Slowly but clearly I began to realize how certainly Kennedy was reconstructing the strange case. But who was it? What was the motive back of this sinister murder that had been so carefully planned that no one would ever suspect a crime?

I had hardly framed the queries when our telephone rang. It was the Central Office man. The detective had anticipated my own line of inquiry, only had gone much further with it. He had found a clear record of the business relations existing between Errol and Marchant. One episode consisted of a stock deal between them in which Errol had invested in a stock which Marchant was promoting and was known to be what brokers call "cats and dogs." That, I reasoned, must have been the basis of the gossip that Errol had suffered financial losses that seriously impaired his little fortune. It was an important item and Kennedy accepted it gladly, but said nothing of his own discovery. The time had not arrived yet to come out into the open.

For a few moments after the talk with the detective Kennedy seemed to be revolving the case, as though in doubt whether the new information cleared it up or added to the mystery. Then he rose suddenly.

"We must find Karatoff," he announced.

Whatever might have been the connection of the hypnotist with this strange case, he was far too clever to betray himself by any such misstep as seeming to avoid inquiry. We found him easily at his studio apartment, nor did we have any difficulty in gaining admittance. He knew that he was watched and that frankness was his best weapon of defense.

"Of course," opened Kennedy, "you know that investigation has shown that you were right in your diagnosis of the trouble with Marchant. Was it arteriosclerosis for which you were treating him?"

"It would be unprofessional to discuss it," hastily parried Karatoff, "but, since Mr. Marchant is now dead, I think I may say that it was. In fact, few persons, outside of those whom I have associated about me, realize to what a wonderful extent hypnotism may be carried in the treatment of disease. Why, I have even had wonderful success with such disorders as diabetes mellitus. We are only on the threshold of understanding what a wonderful thing is the human mind in its effect on the material body."

"But another patient might have known what Marchant was being treated for?" interrupted Kennedy, ignoring the defense of Karatoff, which was proceeding along the stereotyped lines of such vagaries which seem never to be without followers.

Karatoff looked at him a moment in surprise. Evidently he was doing some hasty mental calculation to determine what was Craig's ulterior motive. And, in spite of his almost uncanny claims and performances, I could see that he was able to read Kennedy's mind no whit better than myself.

"I suppose so," he admitted. "No doctor was ever able to control his patients' tongues. Sometimes they boast of their diseases."

"Especially if they are women?" hinted Kennedy, watching the effect of the remark keenly. "I have just had the pleasure of a visit from Carita Belleville in my laboratory."

"Indeed?" returned Karatoff, with difficulty restraining his curiosity. "Miss Belleville has been very kind in introducing me to some of her friends and acquaintances, and I flatter myself that I have been able to do them much good."

"Then she was not a patient?" pursued Kennedy, studiously avoiding enlightening Karatoff on the visit.

"Rather a friend," he replied, quickly. "It was she who introduced Mr. Errol."

"They are quite intimate, I believe," put in Kennedy at a chance.

"Really, I knew very little about it," Karatoff avoided.

"Did she introduce Mr. Marchant?"

"She introduced Mrs. Gaines, who introduced Mr. Marchant," the hypnotist replied, with apparent frankness.

"You were treating Mrs. Gaines?" asked Craig, again shifting the attack unexpectedly.

"Yes," admitted Karatoff, stopping.

"I imagine her trouble was more mental than physical," remarked Kennedy, in a casual tone, as though feeling his way.

Karatoff looked up keenly, but was unable to read Kennedy's face. "I think," he said, slowly, "that one trouble was that Mrs. Gaines liked the social life better than the simple life."

"Your clinic, Mr. Marchant, and the rest better than her husband and the social life at the university," amplified Kennedy. "I think you are right. She had drifted away from her husband, and when a woman does that she has hosts of admirers—of a certain sort. I should say that Mr. Errol was the kind who would care more for the social life than the simple life, as you put it, too."

I did not gather in what direction Kennedy was tending, but it was evident that Karatoff felt more at ease. Was it because the quest seemed to be leading away from himself?

"I had noticed something of the sort," he ventured. "I saw that they were alike in that respect, but, of course, Mr. Marchant was her friend."

Suddenly the implication flashed over me, but before I could say anything Kennedy cut in, "Then Mr. Errol might have been enacting under hypnotism what were really his own feelings and desires?"

"I cannot say that," replied Karatoff, seeking to dodge the issue. "But under the influence of suggestion I suppose it is true that an evil-minded person might suggest to another the commission of a crime, and the other, deprived of free will, might do it. The rubber dagger has often been used for sham murders. The possibility of actual murder cannot be denied. In this case, however, there can be no question that it was an unfortunate accident."

"No question?" demanded Kennedy, directly.

If Karatoff was concealing anything, he made good concealment. Either to protect himself or another he showed no evidence of weakening his first theory of the case.

"No question as far as I know," he reiterated.

I wondered whether Kennedy planned to enlighten him on the results of his laboratory tests, but was afraid to look at either for fear of betraying some hint. I was glad I did not. Kennedy's next question carried him far afield from the subject.

"Did you know that the Medical Society were interested in you and your clinic before the demonstration before Professor Gaines was arranged?"

"I suspected some one was interested," answered Karatoff, quickly, "But I had no idea who it might be. As I think it over now, perhaps it was Professor Gaines who instigated the whole inquiry. He would most likely be interested. My work is so far in advance of any that the conservative psychologists do that he would naturally feel hostile, would he not?"

"Especially with the added personal motive of knowing that his wife was one of your patients, along with Carita Belleville, Marchant, Errol, and the rest," added Kennedy.

Karatoff smiled. "I would not have said that myself. But since you have said it, I cannot help admitting its truth. Don't you suppose I could predict the nature of any report he would make?"

Karatoff faced Kennedy squarely. There was an air almost of triumph in his eyes. "I think I had better say no more, except under the advice of my lawyer," he remarked, finally. "When the police want me, they can find me here."

Quite evident to me now, as we went out of the studio, was the fact that Karatoff considered himself a martyr, that he was not only the victim of an accident, but of persecution as well.

"The fishing was good," remarked Kennedy, tersely, as we reached the street. "Now before I see Errol I should like to see Gaines again."

I tried to reason it out as we walked along in silence. Marchant had known Edith Gaines intimately. Carita Belleville had known Errol as well. I recalled Errol hovering about Mrs. Gaines at the tea and the incident during the seance when Carita Belleville had betrayed her annoyance over some remark by Errol. The dancing by Edith Gaines had given a flash of the jealous nature of the woman. Had it been interest in Errol that had led her to visit the laboratory? Kennedy was weaving a web about some one, I knew. But about whom?

As we passed a corner, he paused, entered a drugstore and called up several numbers at a pay-station telephone booth. Then we turned into the campus and proceeded rapidly toward the laboratory of the psychological department. Gaines was there, sitting at his desk, writing, as we entered.

"I'm glad to see you," he greeted, laying down his work. "I am just finishing the draft of my report on that Karatoff affair. I have been trying to reach you by telephone to know whether you would add anything to it. Is there anything new?"

"Yes," returned Kennedy, "there is something new. I've just come from Karatoff's and on the way I decided suddenly that it was time we did something. So I have called up, and the police will bring Errol here, as well as Miss Belleville. Karatoff will come—he won't dare stay away; and I also took the liberty of calling Mrs. Gaines."

"To come here?" repeated Gaines, in mild surprise. "All of them?"

"Yes. I hope you will pardon me for intruding, but I want to borrow some of your psychological laboratory apparatus, and I thought the easiest way would be to use it here rather than take it all over to my place and set it up again."

"I'm sure everything is at your service," offered Gaines. "It's a little unexpected, but if the others can stand the chaotic condition of the room, I guess we can."

Kennedy had been running his eye over the various instruments which Gaines and his students used in their studies, and was now examining something in a corner on a little table. It was a peculiar affair, quite simple, but conveying to me no idea of its use. There seemed to be a cuff, a glass chamber full of water into which it fitted, tubes and wires that attached various dials and recording instruments to the chamber, and what looked like a chronograph.

"That is my new plethysmograph," remarked Gaines, noting with some satisfaction how Kennedy had singled it out.

"I've heard the students talk of it," returned Kennedy. "It's an improved apparatus, Walter, that records one's blood flow." I nodded politely and concealed my ignorance in a discreet silence, hoping that Gaines would voluntarily enlighten us.

"One of my students is preparing an exhaustive table," went on Gaines, as I had hoped, "showing the effects on blood distribution of different stimuli—for instance, cold, heat, chloroform, arenalin, desire, disgust, fear; physical conditions, drugs, emotions—all sorts of things can be studied by this plethysmograph which can be set to record blood flow through the brain, the extremities, any part of the body. When the thing is charted I think we shall have opened up a new field."

"Certainly a very promising one for me," put in Kennedy. "How has this machine been improved? I've seen the old ones, but this is the first time I've seen this. How does it work?"

"Well," explained Gaines, with just a touch of pride, "you see, for studying blood flow in the extremities, I slip this cuff over my arm, we'll say. Suppose it is the effect of pain I want to study. Just jab that needle in my other arm. Don't mind. It's in the interest of science. See, when I winced then, the plethysmograph recorded it. It smarts a bit and I'm trying to imagine it smarts worse. You'll see how pain affects blood flow."

As he watched the indicator, Kennedy asked one question after another about the working of the machine, and the manner in which the modern psychologist was studying every emotion.

"By the way, Walter," he interrupted, glancing at his watch, "call up and see if they've started with Errol and the rest yet. Don't stop, Gaines. I must understand this thing before they get here. It's just the thing I want."

"I should be glad to let you have it, then," replied Gaines.

"I think I'll need something new with these people," went on Kennedy. "Why, do you know what I've discovered?"

"No, but I hope it's something I can add to my report?"

"Perhaps. We'll see. In the first place, I found that digitalis had been put in Marchant's tea."

"They'll be here directly," I reported from the telephone, hanging it up and joining them again.

"It couldn't have been an accident, as Karatoff said," went on Kennedy, rapidly. "The drug increased the blood pressure of Marchant, who was already suffering from hardening of the arteries. In short, it is my belief that the episode of the rubber dagger was deliberately planned, an elaborate scheme to get Marchant out of the way. No one else seems to have noticed it, but those slips of paper on which we all wrote have disappeared. At the worst, it would look like an accident, Karatoff would be blamed, and—" There was a noise outside as the car pulled up.

"Here, let me take this off before any of them see it," whispered Gaines, removing the cuff, just as the door opened and Errol and Karatoff, Carita Belleville and Edith Gaines entered.

Before even a word of greeting passed, Kennedy stepped forward. "It was NOT an accident," he repeated. "It was a deliberately planned, apparently safe means of revenge on Marchant, the lover of Mrs. Gaines. Without your new plethysmograph, Gaines, you might have thrown it on an innocent person!"



X

THE SUBMARINE MINE

"Here's the bullet. What I want you to do, Professor Kennedy, is to catch the crank who fired it."

Capt. Lansing Marlowe, head of the new American Shipbuilding Trust, had summoned us in haste to the Belleclaire and had met us in his suite with his daughter Marjorie. Only a glance was needed to see that it was she, far more than her father, who was worried.

"You must catch him," she appealed. "Father's life is in danger. Oh, you simply MUST."

I knew Captain Marlowe to be a proverbial fire-eater, but in this case, at least, he was no alarmist. For, on the table, as he spoke, he laid a real bullet.

Marjorie Marlowe shuddered at the mere sight of it and glanced apprehensively at him as if to reassure herself. She was a tall, slender girl, scarcely out of her teens, whose face was one of those quite as striking for its character as its beauty. The death of her mother a few years before had placed on her much of the responsibility of the captain's household and with it a charm added to youth.

More under the spell of her plea than even Marlowe's vigorous urging, Kennedy, without a word, picked up the bullet and examined it. It was one of the modern spitzer type, quite short, conical in shape, tapering gradually, with the center of gravity back near the base.

"I suppose you know," went on the captain, eagerly, "that our company is getting ready to-morrow to launch the Usona, the largest liner that has ever been built on this side of the water— the name is made up of the initials of the United States of North America.

"Just now," he added, enthusiastically, "is what I call the golden opportunity for American shipping. While England and Germany are crippled, it's our chance to put the American flag on the sea as it was in the old days, and we're going to do it. Why, the shipyards of my company are worked beyond their capacity now."

Somehow the captain's enthusiasm was contagious. I could see that his daughter felt it, that she was full of fire over the idea. But at the same time something vastly more personal weighed on her mind.

"But, father," she interrupted, anxiously, "tell them about the BULLET."

The captain smiled indulgently as though he would say that he was a tough old bird to wing. It was only a mask to hide the fighting spirit underneath.

"We've had nothing but trouble ever since we laid the keel of that ship," he continued, pugnaciously, "strikes, a fire in the yard, delays, about everything that could happen. Lately we've noticed a motor-boat hanging about the river-front of the yards. So I've had a boat of my own patrolling the river."

"What sort of craft is this other?" inquired Kennedy, interested at once.

"A very fast one—like those express cruisers that we hear so much about now."

"Whose is it? Who was in it? Have you any idea?"

Marlowe shook his head doubtfully. "No idea. I don't know who owns the boat or who runs it. My men tell me they think they've seen a woman in it sometimes, though. I've been trying to figure it out. Why should it be hanging about? It can't be spying. There isn't any secrecy about the Usona. Why is it? It's a mystery."