Through the open windows of a pleasantly sunny little sitting room a lazy breath of early summer drifted in, and gently stirred the wayward hair of a girl who leaned forward over a small writing desk with her head resting upon one white fore arm, and her face hidden. Her attitude was one of utter collapse, complete abandonment perhaps to grief or perhaps to actual physical suffering; yet there was no movement of the slender, graceful body, nothing to indicate even a passive interest in her surroundings — just this silent, motionless figure, alone.

One arm, the left, swung down listlessly at her side, and in that hand she held a single red rose, a splendid, full blown crimson blossom. The thorny stem touched the floor, and the leaves swayed rhythmically, playthings of the caressing breeze. On the green stem, just below the girl’s tightly clenched hand, was a single stain — a drop of blood — as if the thorn had pierced the delicate flesh. On the desk, from which dainty writing trinkets had been pushed back, was a florist’s box, open. It was from this box evidently that the red rose had been taken. The wax paper which had been wrapped round the flower was torn.

A Dresden clock on the mantel whirred faintly and chimed the hour of five; but the girl gave not the slightest indication of having heard. And then after a moment a door opened and a maid appeared. She paused as her eyes fell upon the figure of the young woman, made as if to speak, then instead silently withdrew, leaving the door slightly open. She did not seem surprised that no notice was taken of her. A dozen times she had found her young mistress like this, and it was always after the box had come from the florist’s with the single red rose. She sighed a little as she went out.

The hands of the clock crept on round the dial slowly, to five minutes past the hour, then to ten, and finally to fifteen. Then there came a scampering of soft feet along the hall, and a white, shaggy little dog thrust his head in at the door inquisitively. Helterskelter he came tumbling in and planted two soiled fore feet in the girl’s lap as he awaited the caress which was always ready for him. Now it didn’t come. He backed away and regarded her thoughtfully. It must be some new sort of game she was playing. He crouched on the floor and barked playfully; but she didn’t look round.

Evidently this was not what was expected of him. He scampered back and forth across the room twice, then returned to the motionless figure and placed his feet in her lap again. She wouldn’t look. He barked, whined softly, then off like the wind round the room again. He stopped on her left side this time — the side where the arm swung down, and the hand clutched the rose. His moist tongue caressed the closed hand, and sniffed at it insistently. Suddenly he seemed dazed, and reeled uncertainly as if from an unexpected blow. He whined again as if choking; there was a rattle in his shaggy throat; and then began a violent whirling, twisting, which continued till he fell. After awhile he lay still with all four feet turned upward and glazed, staring eyes. And yet the girl hadn’t moved.

The hands of the clock crept on. At five minutes of six o’clock the maid appeared at the door again, paused for a moment, then ventured in. “Will you dress for dinner, ma’am?” she inquired.

The girl didn’t answer.

“It’s nearly six o’clock, ma’am,” said the maid.

Still there was no answer.

The maid approached her young mistress and touched her lightly on the shoulder. “You’ll be late, unless —” she began.

And then something about the unresisting, impassive figure frightened her. She shook the girl sharply and called her name many times. Finally with an effort she raised the shapely head. What she saw in the upturned face wrung scream after scream from her lips, now suddenly ashen, and turning she staggered toward the door with unutterable horror in her widely distended eyes. She clutched at the door frame to steady herself, screamed again, and fell forward, fainting. There they found them: Miss Edna Burdock dead with hideously distorted face — a face upon which was written some awful agony — and the rose still clasped so fiercely in her hand that the thorns had pierced the palm; her little dog Tatters dead beside her; and the maid, Goodwin, unconscious. For half an hour two servants worked over the maid; but when at last she opened her eyes she only screamed and babbled incoherently. There were no marks on Miss Burdock’s body save the prick of thorns in her left hand — nothing that would indicate the manner of death; nor was there the slightest thing to explain the death of the dog.

“The police are not at all certain that Miss Burdock’s death was due to anything more mysterious than heart failure,” Hutchinson Hatch, reporter, was explaining. “In that event, of course —”

“In that event, of course,” interrupted Professor Augustus S. F. X. Van Dusen — The Thinking Machine — crabbedly, “their theory must be that the pet dog died at the same time of the same disease?”

“That seems to be about the way they look at it, although there are several curious features,” the reporter went on; “for instance, the expression on her face.” He shuddered a little. “I saw her. It was awful. The dog too. There was not a mark or scratch on the dog — not even the prick of a thorn like that in the girl’s palm, therefore heart failure seems to be the only thing that will cover the case, unless —”

“Fidldesticks!” exclaimed the irritable little scientist. “Persons who die of heart failure don’t show suffering in their faces, and little dogs don’t have heart failure. What did the autopsy show?”

“Nothing illuminating,” responded the reporter. “There was no trace of poison in Miss Burdock’s system; a blood test showed her blood to be about normal, and yet she was dead. There was a peculiar constriction of the heart, and the same thing was true of the dog. The medical examiner’s report brought out these facts; but there was no poison — they were just dead.”

“When did this happen, Mr. Hatch?”

“Yesterday afternoon, Monday.”

“You tell me the maid found the body. Has she said anything about noticing any odor when she entered the room?”

“Not a word; but there are curious things —”

“In a minute, Mr. Hatch,” interrupted The Thinking Machine impatiently. “Were the windows open?”

“Yes,” replied the reporter. “She was sitting at her desk, between two open windows.”

The man of science dropped back in his chair, and for a long time sat silent with the perpetually squinting eyes turned upward, and slender white fingers pressed tip to tip. Hatch lighted a cigarette, smoked it, and threw the butt away before he spoke.

“There are peaches in the market, I think, Mr. Hatch,” said the scientist at last. “When you go out, buy one, cut the meat off, crush the kernel, take it to the maid, and ask her to smell it. Ask her if she noticed yesterday any odor similar to that when she entered the room and was near the girl’s body.”

Hatch absorbed the instructions wonderingly, then ventured a remark. “I presume you are thinking of poison. Isn’t there a chance that despite the normal condition of her blood some sort of poison was introduced into her system — I mean that the thorns of the rose might have been poisoned, for instance.”

“You say there was no scratch or thorn prick on the dog?” asked The Thinking Machine in answer.

“No mark of any sort.”

“And the dog is dead. That answers your question, Mr. Hatch.” He relapsed into silence.

“Poison on the thorns could not have killed both of them, because only the woman’s hand showed the marks?” Hatch asked.

“Precisely,” was the reply. “Unless we allow for coincidence, and that has never been reduced to a scientific law, we must say that both the woman and the dog died of the same cause. When we know that, we prove that the thorn prick had nothing to do with the woman’s death. Two and two make four, Mr. Hatch, not sometimes but all the time. And so what have we left?”

“I don’t see that we have anything left,” remarked Hatch frankly. “If there is no outward cause, how can we —”

“The mere fact that there is no apparent cause, or outward cause, as you term it, makes the manner of death of both the woman and the dog perfectly plain,” declared The Thinking Machine belligerently. “There is no mystery about that at all — it’s obvious. Our problem is not what killed her, but who killed her.”

“Yes, that seems quite clear,” the reporter admitted.

Minute after minute passed while the scientist sat staring upward. Finally he lowered his eyes to the face of the newspaper man. “Where did this red rose come from?” he demanded.

“I was going to tell you about that,” responded Hatch. “It came from Lamperti’s, a florist. The police are investigating it now. It seems, according to a statement of the manager of the shop, that on June 16 he received a special delivery letter from Washington with only a typewritten, unsigned slip of paper inclosed. This directed that one dozen red roses be sent to Miss Burdock, one at a time on specified days, Mondays, Wednesdays, and Saturdays. They accepted the order — there was no way to return the money anyway — and so —”

He paused to gaze curiously into the eyes of The Thinking Machine. They were drawn down to mere slits of watery blue and some subtle change had altered the straight line of the lips.

“Well, well!” grumbled the scientist. “Go on!”

“As a rule the long box with the one rose was delivered at the house by one of the wagons of the company,” the reporter continued; “but some days when the wagon was not going in that direction the box was sent by a messenger boy. This last rose went to her by messenger.”

“And have all the roses been sent?”

“So the manager says.”

“And where is the red rose — the one she had in her hand when found?”

“Detective Mallory has it in charge, I suppose,” explained the reporter. “He has an idea that Miss Burdock was killed by poison on the thorns; so he stripped them off and sent them to a chemist to see if any trace of poison could be found. I presume he kept the flower and the box it came in.”

“That’s just like Mallory,” commented the scientist testily. “Whenever the police want to keep a cat’s teeth from falling out they cut off its tail. Now tell me something about Miss Burdock herself. Who was she? What was she? What were her circumstances?” He settled back in his chair for a categorical answer.

“She was the only daughter of Plympton Burdock; a man who is not wealthy, but who is well to do,” answered Hatch. “She lived at home with her father, her mother, and a younger brother, a chap about eighteen or nineteen years old. She was something of a social favorite, although not yet quite twenty-one, and went about a great deal; so —”

“So naturally a great many men, some of whom admired her,” The Thinking Machine finished for him. “Now who are the men? Tell me about her love affairs?”

“It hasn’t appeared yet that there was a love affair, in the sense you mean. At least, if there was no one knew of it.”

“Doesn’t the maid Goodwin know?” insisted the scientist.

“She says she doesn’t.”

“But somebody sent the rose. The mere fact that she received the one rose a dozen times indicates that some one was interested in her. Therefore, who was it? Who?”

“That’s what the police are trying to find out now.”

The Thinking Machine arose suddenly, picked up his hat and planted it aggressively on his enormous yellow head. “I’m going to the florist’s,” he said. “You get the peach and see the maid Goodwin. Meet me at police headquarters in an hour.”

It required ten minutes for The Thinking Machine to reach the florist’s shop, and in five minutes more the manager was at liberty.

“All I want to know,” the scientist explained, “is the day you sent the first rose of that dozen to Miss Burdock, and I should like to see your records of delivery. That is, when a package is delivered either by your wagon or by messenger you get a receipt for it? Yes. I should like to see those, please.”

The manager obligingly consulted his records. “The letter with the inclosure was received on June 16,” he explained as he ran his finger down the book. “It came in the morning mail. June 16 was Monday; therefore the first rose of the dozen was sent that afternoon, Monday.”

“Are you absolutely certain of that?” demanded The Thinking Machine. “A— a person’s life may depend on that record.”

The manager stared at him in frank astonishment, then arose. “I can make sure,” he said. He went to a cabinet and took out another book — a delivery receipt book, and fluttered the leaves through his fingers. At last he laid it before The Thinking Machine and indicated an entry with his finger. “There it is,” he said. “Monday, June 16, at five-thirty in the afternoon. The book was signed by Edna Burdock in person. See.”

The Thinking Machine squinted down at the entry for a minute or more in silence. “From that date forward one rose was sent every Monday, Wednesday, and Saturday without a break until the dozen were delivered?” he asked at last.

“Yes; that was the direction. Run through the book on the dates it should have been sent and see, if you like.”

The scientist heeded the suggestion, and for ten minutes or so was engrossed in the record. “These slips?” he inquired, as he looked up. “I find three of them.”

“Those were the occasions when we didn’t happen to have a wagon going in that direction,” the manager explained; “so the box was sent by special messenger. Each messenger took a receipt and returned it here. In that way those receipts became a part of our record.”

The Thinking Machine scrutinized the slips carefully, made a note of the dates on them, then closed the record book. That seemed to be all. Fifteen minutes later Plympton Burdock, father of the dead girl, received a card from a servant, glanced at it, nodded, and The Thinking Machine was ushered in.

“I should not have disturbed you, believe me, if the necessity for it had not been pressing in the interest of justice,” the scientist apologized. “Just one or two questions, please.”

Burdock regarded the little man curiously, and motioned to a seat.

“First,” began The Thinking Machine, “was your daughter engaged to be married at the time of her — her death?”

“No,” replied Burdock.

“She did receive attention, however?”

“Certainly. All girls of her age do. Really, Mr. — Mr.,” and he glanced at the card — “Mr. Van Dusen, this matter is entirely beyond discussion. We believe, my wife and I, that death was due to natural causes, and have so informed the police. I hope it may go no further.”

The Thinking Machine looked at him sharply with some strange new expression in his squint eyes. “The investigation won’t stop now, Mr. Burdock,” he said coldly. “I don’t know your object in-in seeking to stop it.”

“I don’t want to stop it,” declared Burdock quickly. “We are convinced that no good can come of an investigation, because there is no ground for suspicion, and certainly it is not pleasant to have one’s family affairs constantly pawed over when it is a foregone conclusion that nothing will result except unpleasant notoriety which merely adds to the burden that we now have to bear.”

The Thinking Machine understood and nodded. It was almost an apology. “Well, just one more question, please,” he said. “What is the name of the man whose attentions to your daughter you in person forbade?”

“How do you know of that?” blazed Burdock quickly.

“What is his name?” repeated The Thinking Machine.

“I will not discuss the matter further with you,” was the reply.

“In the interests of justice I demand his name!” The Thinking Machine insisted.

Burdock stared at the slight figure before him with growing horror in his face. “You don’t mean to say you suspect —” He stopped. “My God! if I thought that I’d — How was she killed, if she was killed?” he concluded.

“His name, please,” urged The Thinking Machine. “If you don’t give it to me, you will place me under the necessity of asking the police to compel you to give it. I’d prefer not to.”

Burdock seemed not to heed the speech. His face had gone perfectly white, and he stood staring past the scientist, out the window. His hands were clenched tightly and the fingers were working. “If he did! If he did!” he repeated fiercely. Suddenly he recovered himself and glared down at his visitor. “I beg your pardon,” he said simply. His name is — is Paul K. Darrow.”

“Of this city,” said The Thinking Machine. It was not a question; it was a statement of fact.

“Of this city,” repeated Burdock — “at least formerly of this city. He left here, I am informed, four or five weeks ago.”

The Thinking Machine went his way, leaving Burdock sitting with his face in his hands. A few minutes later he appeared in Detective Mallory’s office at police headquarters. The officer was sitting with his feet on his desk, smoking furiously, with a dozen deep wrinkles in his brow. He hailed the scientist almost cordially, something unusual for him.

“What do you make of it?” he demanded as he arose.

“Let me see your directory for a moment, please,” replied The Thinking Machine. He bent over the book, ran down a page or so of the D’s, then finally looked up.

“We don’t seem to be able to establish a crime, even,” Detective Mallory confessed. “I had the thorns examined, and the chemist reports that there is not a trace of poison about them.”

“Silly in the first place,” remarked The Thinking Machine ungraciously enough. “Is the rose here?”

The detective produced it from a drawer of his desk, whereupon The Thinking Machine did several things with it which he didn’t understand. First he waved it about in the air at arm’s length, then took two steps forward and sniffed. Then he waved it about much closer to him and sniffed. Detective Mallory looked on in mingled curio............