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 curiosity and disgust. finally the scientist held it close to his nose and sniffed, then examined the petals closely, after which he laid it on the desk again.
“and the box the rose was delivered in?” queried the scientist.
silently the detective produced that. the thinking machine sniffed at it cautiously, then turned it over to examine the handwriting on the address.
“know who wrote this?” he inquired.
“some one at the florist’s,” was the reply.
“can you lend me a man for half an hour or so?” asked the scientist next.
“oh, i suppose so,” grumbled detective mallory. “but what’s it all about, anyway?”
“perhaps i may be able to tell you at the end of the half hour,” the thinking machine assured him. “meanwhile lend me the man you said i could have.”
detective downey was called in, and the diminutive scientist led him into the hall, where he gave him some definite directions. downey went out the front door at full speed. the thinking machine returned to detective mallory’s private room, to find the officer sulking, like a boy.
“where’d you send him?” he growled.
“wait till he comes back and i’ll tell you,” was the reply. “it isn’t necessary to get excited about something that we know nothing of. i’m saving you some excitement.”
he dropped back into a chair and sat there idly twiddling his thumbs while detective mallory glared at him. after a few minutes the door was thrown open violently and hutchinson hatch entered. he was frankly excited.
“well?” demanded the thinking machine without looking round.
“when she smelled that crushed kernel she fainted!” said hatch explosively.
“fainted?” repeated the scientist. “fainted?” the tone was hardly one of surprise, and yet —“yes, she took one whiff, and screamed and went right over,” the reporter rushed on. “dear me! dear me!” commented the thinking machine. he sat still looking up. “wait a few minutes,” he advised. “let’s see what downey gets.”
at the end of fifteen minutes downey returned. his chief glared at him curiously as he entered and handed a piece of paper to the thinking machine. that imperturbable man of science examined the paper closely, then handed it to detective mallory.
“is that the handwriting on the flower box?” he asked.
mallory, downey, and hatch compared it together. the verdict was unanimous: “yes.”
“then the man who wrote it is the man you want,” declared the thinking machine flatly. “his name is paul k. darrow. detective downey knows his address.”
two days passed. professor van dusen stood beside his laboratory table poking idly at the dismembered legs of a frog with a short copper wire. each time the point touched the flesh there was a spasmodic twitching of the limbs, a simulation of living contraction and extension. there beside the table hutchinson hatch found him.
“watch this a moment, mr. hatch,” requested the scientist. “it bears, in a way, on our problem in hand.”
then began a rhythmic swinging of his slender hand, not unlike the beat of the musician’s baton, the wire touching the frog’s legs at each downward swing. hatch had seen a similar demonstration before.
“watch the strokes,” said the scientist, “and watch the legs after the twentieth.”
“fourteen, fifteen, sixteen,” hatch counted. each time the wire touched, and each time came the spasmodic motion. “seventeen, eighteen, nineteen, twenty.”
the thinking machine, instead of touching the twenty-first time, held the wire aloft. at the instant it would have touched the flesh, according to the beat, there came the same quick, spasmodic twitch, and then the legs were still.
“you see the effect is precisely as if i had touched them the twenty-first time,” explained the thinking machine, “and that, mr. hatch, is one of the things science doesn’t attempt to explain. it can be explained some day — it will be explained, but —” he paused. “darrow hasn’t been captured yet?” he said.
“no; no trace of him yet,” was the reply. “the police have sent out a general alarm for him all over the country, and today burdock increased the reward he offered from five thousand to ten thousand dollars.”
“one of my objections to dealing with the police is that they are prone to jump at conclusions,” remarked the thinking machine. “i didn’t say, of course, that darrow was a murderer. he may have killed miss burdock — he probably did — but it isn’t conclusive at all. still he is the next link in the chain, so his presence is necessary.”
hatch gazed at him in amazement, and a hundred questions rushed to his lips. they were stilled by the sudden appearance in the doorway of a young man. a soft hat was pulled down over his eyes, and he was crouching as if about to spring. one hand, the right, was in his coat pocket, clutching something fiercely. his face was perfectly pallid, and roving, glittering eyes blazed with madness.
“come in,” suggested the thinking machine calmly.
“i— i must talk to you, quick!” the young man burst out. “it’s a matter of the most vital importance, and —”
“i’m at your service, mr. darrow,” remarked the thinking machine pleasantly. “have a seat.”
darrow! hatch was startled, made speechless, by the uncanny appearance of this man whom the police of the entire continent were seeking. darrow was still crouching there in the doorway, staring at them.
“i risked everything to come here,” declared the young man — and there was a menace in his tone. “i was on the stoop about to ring the bell when i glanced back and saw detective mallory turn the corner. i didn’t wait to ring — the door was unfastened and i came on in. mallory is probably coming here. i must talk to you — and i won’t be taken alive. do you understand what i say?”
“perfectly,” replied the thinking machine. “mr. mallory won’t see you. come in out of the door.”
“no tricks!” warned darrow fiercely.
“no tricks. sit down.”
with furtive glances to right and left along the hall, the young man entered and dropped into a seat in a corner, facing them. there was a long, tense silence, and finally the door bell rang. darrow half rose and made as if to take his right hand from his pocket.
“that’s mallory,” remarked the thinking machine, and he started toward the door.
darrow took one step forward, blocking his way. “understand, please,” he began in a low, even voice. “i am utterly desperate, and i won’t be taken! if you attempt to betray me, i—” he stopped.
the thinking machine walked round him to the door leading into the hall. martha, his aged servant, was just passing.
“mr. mallory is at the door, martha,” said the scientist. “tell him i am not in; but that i shall be at police headquarters within an hour, and mr. darrow will come with me.”
he stepped back into the laboratory and closed the door, without even a glance at his visitor. they heard martha open the front door, then they heard mallory’s heavy voice, finally martha’s answer, then the door was closed, and martha’s footsteps passed along the hall. darrow suddenly rushed to the window and glanced out.
“all right, mr. darrow,” remarked the little scientist, as he sat down. “i know now you are innocent; i know why you have been hiding out, i know why you came here to see me, and i understand too your deep grief; so we can come immediately to the vital things.”
the young man turned and glared at the small, impassive figure. “you said i would be at police headquarters with you in an hour,” he said accusingly.
“certainly,” agreed the scientist impatiently. “as an innocent man you will go there of your own free will, with me.”
the young man dropped into a chair and sat there for a long time with his face in his hands. after awhile hatch saw a teardrop trickle through the unsteady fingers, and the shoulders moved convulsively. the thinking machine sat with head tilted back, squinting upward and fingers at rest, tip to tip.
“this trouble between you and mr. burdock?” suggested the scientist at last.
“you don’t know the malignant hatred he has for me,” said darrow suddenly. “he is not a man of great wealth, but he is a man of great power, great influence, and if i should fall into the hands of the police with the circumstantial case against me that now exists he would bring all that power and influence to bear against me, with the result that i should be railroaded to a felon’s grave. i don’t know just how he would do it; but he would do it. i’m afraid of him — that’s why i came here to see you when i wouldn’t dare go to the police. i won’t be taken by the police until i know i can prove my innocence; then i will surrender.”
the thinking machine nodded.
“the enmity existing between us is of years’ standing, and is not of importance here,” darrow went on. “but i know this man’s power — i have felt it all my life — he has brought me to the edge of starvation half a dozen times, pursued me in every walk of life, until now — now if i should have to commit murder, he would be the victim. i’m telling you this because —”
“all this is of no consequence,” interrupted the thinking machine shortly. “who poisoned the rose?”
“i don’t know,” replied darrow helplessly.
“you must have some idea,” insisted the thinking machine.
“i did have an idea,” was the reply. “i went this morning to a place to see a — a person whom i intended to accuse openly of the crime, taking the chance of capture myself, much as i dreaded it; but there was no one there. the door was locked; a servant connected with the apartment house told me that the — the person had not been there for a day or so.”
the thinking machine turned quickly in his chair and glared at darrow curiously.
“what’s her name?” he demanded sharply.
“i don’t know that she could have had anything to do with it,” warned darrow. “it seems awful to suggest such a thing, and yet —” he stopped. “i will go there with you to see her if you wish.”
“mr. hatch,” directed the thinking machine, “step into the next room there and telephone for a cab.” he turned again to darrow. “she threatened you, or miss burdock, i imagine?”
“yes,” said darrow reluctantly.
“and now, please, one last question,” said the little scientist. “what relation existed between you and miss burdock?”
“she was my wife,” darrow replied in a low voice. “we were secretly married four months ago.”
“um-m,” mused the scientist. “i imagined as much.”
detective mallory impatiently strode back and forth across his private office, his brain turbulent with conjecture. the telephone bell rang; the thinking machine was at the other end of the wire.
“come at once and bring the medical examiner to the craddock apartments!” commanded the irritable voice of the little scientist.
“another murder?” demanded the detective, aghast.
“no, a suicide,” was the reply. “good by.”
detective mallory and medical examiner francis found the thinking machine, hutchinson hatch, and paul k. darrow in the sitting room of a small apartment on the fourth floor. some sinister thing lay outstretched on a couch, covered with a sheet.
“mr. mallory, this is mr. darrow,” the scientist remarked. “and here,” he indicated the couch, “is the woman who murdered miss burdock, or rather mrs. darrow. her name is maria di peculini. here is a full confession in her own handwriting,” he passed an envelope to the detective, “and here are several torn pieces of paper which show how assiduously she practised before show forged mr. darrow’s handwriting in addressing the box in which the red rose was sent to miss — i should say mrs. darrow. i may add that signorina di peculini killed herself by inhaling hydrocyanic acid — perhaps you know it better as prussic acid — in a bottle from which came the single drop, allowed to settle in the bloom of the rose, which killed mrs. darrow.”
detective mallory remained standing still for a long time to take it all in. at last he opened the confession — only a dozen lines — and read it from end to end. it was a pitiful, disjointed, almost incoherent, revelation of a woman’s distorted soul. she too had loved darrow, and this had changed to hate when he drifted away from her. then, when by her own hand she had removed the woman he had made his wife, and had sought subtly to place the blame on him by the little forgery — then had come a revulsion of feeling. she loved again, and overcome by remorse sought relief in death.
“there was no mystery whatever as to the cause of death,” the thinking machine told detective mallory and hatch a little while later. “murder by poison was obvious from the fact that both the woman and the dog were dead; and when we knew that there was no mark or scratch on the dog, and the autopsy revealed nothing, we knew by the simplest rule of logic that the poison had been inhaled. the most powerful poison to inhale is hydrocyanic acid — it kills instantly — therefore it occurred to me first. it is so powerful that it is never made pure, at least in this country. the strongest you can buy in a drug store, for instance, is about a two per cent solution. one drop of a stronger solution than that, on a rose bloom, would have killed miss burdock, and the dog if he sniffed at it, as he must have.
“therefore, from the very first, we knew the manner of death. when we knew further that hydrocyanic acid is extremely volatile, we see how that single drop on the rose evaporated, was dissipated in the air, as the windows of the room where the young woman was found were open. still there was a faint odor of it left — it smells precisely like crushed peach kernels — and the maid goodwin was unconsciously affected by it.
“knowing these things,” he continued, “i went to the florist’s. only twelve roses had been bought, paid for, and delivered from there, and the rose that killed miss burdock was the thirteenth rose. the roses went from the florist’s mondays, wednesdays, and saturdays for four weeks, making twelve roses. they had all been delivered, as the receipt books there showed; but miss burdock was killed on monday; therefore that was the thirteenth rose, and it didn’t come direct from the florist’s. it was sent by messenger, and the date didn’t correspond with any date in the receipt book; therefore it came from another source.
“incidentally the fact that the roses were sent in that way — that is one at a time without a card or suggestion of by whom they were sent — suggested a clandestine arrangement with the girl. in other words, the roses were being sent by some one she knew, in all probability; but no one else must know. it was, i saw, a method of correspondence, i might say a love token of some sort, which would not attract attention at her home as a letter would.
“thus i established a relationship between miss burdock and some one else — unknown. the logic of it all informed me that the reason that unknown didn’t communicate with her was because of some objection in her home. her father! do you see? i simply asked him about it, and instantly his hatred for a single individual came out, that individual being mr. darrow. thus, things pointed toward mr. darrow, who was away. the letter to the florist was from washington. the joints were fitting nicely.
“at police headquarters i saw the rose, and by cautious experiments detected a faint odor of peach kernels. then i saw the handwriting on the box. it seemed to be a man’s; yet i knew by the receipt book there that it did not come from the florist’s, therefore was not addressed by anyone there. did mr. darrow address it? mr. downey got for me a sample of mr. darrow’s writing (i don’t know how he got it), and the two were compared. they seemed to be the same. this fact was connecting with all the others. clandestine communication — poison — darrow! do you see? this development made darrow’s presence necessary, and i told you, mr. mallory, that he was the man we must find. yet, from the fact that the handwriting on the box was his i had a first suggestion that he was not guilty of the crime. no intelligent man would address a box like that in his own handwriting.
“the matter rested at this point. mr. burdock accepted a murder theory and offered rewards, and then mr. darrow in person came to see me. the moment he stepped inside my door, to tell me an improbable story, i knew he was innocent. mr. burdock’s hatred of him (the cause of the feud between them is not of consequence) told me why he had disappeared; and his mere appearance before me accounted for his not going to the police. so — so that’s all. he told me of calling to see signorina di peculini, and she was not in. we came here, found the door locked, went in with a pass key, and found the things as i delivered them to you, mr. mallory.” he stopped and sat silently staring for a little while.
“briefly,” he supplemented, “the woman who killed herself knew of the rose being sent regularly, then determined on revenge, bought one, and sent it herself after dropping a single drop of poison in the bloom. the wax paper which surrounded the flower prevented evaporation, and when it was opened — we know the rest.”
neither detective mallory nor hatch spoke for a long time. but the reporter had one more question to ask; and at last he put it.
“that peach kernel that you sent me to goodwin with —” he began.
“oh, yes,” interrupted the thinking machine. “that was a little psychological experiment, and the result of it disconcerted me a little. it is one of the many things science doesn’t fully understand, mr. hatch — like the little experiment with the frog. for instance, nitrite of amyl is a powerful heart stimulant. it smells precisely like banana oil. a person who has used nitrite of amyl, or to whom it has been administered without their knowledge by inhalation, is momentarily affected the same way when they come suddenly upon the odor of banana oil. prussic acid has an odor like a peach kernel. i sent you to goodwin, therefore, to prove definitely whether or not prussic acid had been used, and if she had inhaled it unconsciously. the result gave the proof i wanted.”