From his inner sanctum, Average Jones stared obliquely out upon the whirl of Fifth Avenue, warming itself under a late March sun.

In the outer offices a line of anxious applicants was being disposed of by his trained assistants. To the advertising expert's offices had come that day but three cases difficult enough to be referred to the Ad-Visor himself. Two were rather intricate financial lures which Average Jones was able to dispose of by a mere “Don't.” The third was a Spiritualist announcement behind which lurked a shrewd plot to entrap a senile millionaire into a marriage with the medium. These having been settled, the expert was free to muse upon a paragraph which had appeared in all the important New York morning papers of the day before.

“That's too much money for a dog,” decided Average Jones. “Particularly one that hasn't any bench record. I'll just have a glance into the thing.”

Slipping on his coat he walked briskly down the avenue, and crossing over to Union Square, entered the gloomy old building which is the sole survival of the days when the Stengel estate foresaw the upward trend of business toward Fourteenth Street. Stepping from the elevator at the seventh floor, he paused underneath this sign:

Entering, Average Jones found a fat young man, with mild blue eyes, sitting at a desk.

“Mr. Dorr?” he asked.

“Yes,” replied the fat young man nervously, “but if you are a reporter, I must—”

“I am not,” interrupted the other. “I am an expert on advertising, and I want that one thousand dollars reward.”

The chemist pushed his chair back and rubbed his forehead.

“You mean you have—have found out something?”

“Not yet. But I intend to.”

Dorr stared at him in silence.

“You are very fond of dogs, Mr. Dorr?”

“Eh? Oh, yes. Yes, certainly,” said the other mechanically.

Average Jones shot a sudden glance of surprise at him, then looked dreamily at his own finger-nails.

“I can sympathize with you. I have exhibited for some years. Your dog was perhaps a green ribboner?”

“Er—oh—yes; I believe so.”

“Ah! Several of mine have been. One in particular, took medal after medal; a beautiful glossy brown bulldog, with long silky ears, and the slender splayed-out legs that are so highly prized but so seldom seen nowadays. His tail, too, had the truly Willoughby curve, from his dam, who was a famous courser.”

Mr. Dorr looked puzzled. “I didn't know they used that kind of dog for coursing,” he said vaguely.

Average Jones smiled with almost affectionate admiration at the crease along the knee of his carefully pressed trousers. His tone, when next he spoke, was that of a youth bored with life. Any of his intimates would have recognized in it, however, the characteristic evidence that his mind was ranging swift and far to a conclusion.

“Mr. Dorr,” he drawled, “who—er—owned your—er—dog?”

“Why, I—I did,” said the startled chemist.

“Who gave him to you?”

“A friend.”

“Quite so. Was it that—er—friend who—er—offered the reward?”

“What makes you think that?”

“This, to be frank. A man who doesn't know a bulldog from a bed-spring isn't likely to be offering a thousand dollars to avenge the death of one. And the minute you answered my question as to whether you cared for dogs, I knew you didn't. When you fell for a green ribbon, and a splay-legged, curly-tailed medal-winner in the brindle bull class (there's no such class, by the way), I knew you were bluffing. Mr. Dorr, who—er—has been—er—threatening your life?”

The chemist swung around in his chair.

“What do you know?” he demanded.

“Nothing. I'm guessing. It's a fair guess that a reasonably valuable brindle bull isn't presented to a man who cares nothing for dogs without some reason. The most likely reason is protection. Is it in your case?”

“Yes, it is,” replied the other, after some hesitation.

“And now the protection is gone. Don't you think you'd better let me in on this?”

“Let me speak to my—my legal adviser first.”

He called up a down-town number on the telephone and asked to be connected with Judge Elverson. “I may have to ask you to leave the office for a moment,” he said to his caller.

“Very well. But if that is United States District Attorney Roger Elverson, tell him that it is A. V. R. Jones who wants to know, and remind him of the missing letter opium advertisement.”

Almost immediately Average Jones was called back from the hallway, whither he had gone.

“Elverson says to tell you the whole thing,” said the chemist, “in confidence, of course.”

“Understood. Now, who is it that wants to get rid of you?”

“The Paragon Pressed Meat Company.”

Average Jones became vitally concerned in removing an infinitesimal speck from his left cuff. “Ah,” he commented, “the Canned Meat Trust. What have you been doing to them?”

“Sold them a preparation of my invention for deodorizing certain by-products used for manufacturing purposes. Several months ago I found they were using it on canned meats that had gone bad, and then selling the stuff.”

“Would the meat so treated be poisonous?”

“Well—dangerous to any one eating it habitually. I wrote, warning them that they must stop.”

“Did they reply?”

“A man came to see me and told me I was mistaken. He hinted that if I thought my invention was worth more than I'd received, his principals, would be glad to take the matter up with me. Shortly after I heard that the Federal authorities were going after the Trust, so I called on Mr. Elverson.”

“Mistake Number One. Elverson is straight, but his office is fuller of leaks than a sieve.”

“That's probably why I found my private laboratory reeking of cyanide fumes a fortnight later,” remarked Dorr dryly. “I got to the outer air alive, but not much more. A week later there was an explosion in the laboratory. I didn't happen to be there at the time. The odd feature of the explosion was that I hadn't any explosive drugs in the place.”

“Where is this laboratory?”

“Over in Flatbush, where I live—or did live. Within a month after that, a friendly neighbor took a pot-shot at a man who was sneaking up behind me as I was going home late one night. The man shot, too, but missed me. I reported it to the police, and they told me to be sure and not let the newspapers know. Then they forgot it.”

Average Jones laughed. “Of course they did. Some day New York will find out that 'the finest police force in the world' is the biggest sham outside the dime museum. Except in the case of crimes by the regular, advertised criminals, they're as helpless as babies. Didn't you take any other precautions?”

“Oh, yes. I reported the attempt to Judge Elverson. He sent a secret service man over to live with me. Then I got a commission out in Denver. When I came back, about a month ago, Judge Elverson gave me the two dogs.”

“Two?”

“Yes. Rags and Tatters.”

“Where's Tatters?”

“Dead. By the same road as Rags.”

“Killed at your place in Flatbush?”

“No. Right here in this room.”

Average Jones became suddenly very much worried about the second button of his coat. Having satisfied himself of its stability, he drawled, “Er—both of—er—them?”

“Yes. Ten days apart.”

“Where were you?”

“On the spot. That is, I was here when Tatters got his death. I had gone to the wash-room at the farther end of the hall when Rags was poisoned.”

“Why do you say poisoned?”

“What else could it have been? There was no wound on either of the dogs.”

“Was there evidence of poison?”

“Pathological only. In Tatters case it was very marked. He was dozing in a corner near the radiator when I heard him yelp and saw him snapping at his belly. He ran across the room, lay down and began licking himself. Within fifteen minutes he began to whine. Then he stiffened out in a sort of a spasm. It was like strychnine poisoning. Before could get a veterinary here he was dead.”

“Did you make any examination?”

“I analyzed the contents of his stomach, but did not obtain positive results.”

“What about the other dog?”

“Rags? That was the day before yesterday. We had just come over from Flatbush and Razs was nosing around in the corner—”

“Was it the same corner where Tatters was attacked?”

“Yes, near the radiator. He seemed to be interested in something there when I left the room. I was gone not more than two minutes.”

“Lock the door after you?”

“It has a special spring lock which I had put on it.”

Average Jones crossed over and looked at the contrivance. Then his glance fell to a huge, old-fashioned keyhole below the new fastening. “You didn't use that larger lock?”

“No. I haven't for months. The key is lost, I think.”

Retracing his steps the investigator sighted the hole from the radiator, and shook his head.

“It's not in range,” he said. “Go on.”

“As I reached the door on my return, I heard Rags yelp. You may believe I got to him quickly. He was pawing wildly at his nose. I called up the nearest veterinary. Within ten minutes the convulsions came on. The veterinary was here when Rags died, which was within fifteen minutes of the first spasm. He didn't believe it was strychnine. Said the attacks were different. Whatever it was, I couldn't find any trace of it in the stomach. The veterinary took the body away and made a complete autopsy.”

“Did he discover anything?”

“Yes. The blood was coagulated and on the upper lip he found a circle of small pustules. He agreed that both dogs probably swallowed something that was left in my office, though I don't see how it could have got there.”

“That won't do,” returned Average Jones positively. “A dog doesn't cry out when he swallows poison, unless it's some corrosive.”

“It was no corrosive. I examined the mouth.”

“What about the radiator?” asked Average Jones, getting down on his knees beside that antiquated contrivance. “It seems to have been the center of disturbance.”

“If you're thinking of fumes,” replied the chemist. “I tested for that. It isn't possible.”

“No; I suppose not. And yet, there's the curious feature that the fatal influence seems to have emanated from the corner which is the most remote from both windows and door. Are your windows left open at night?”

“The windows, sometimes. The transom is kept double-bolted.”

“Do they face any other windows near by?”

“You can see for yourself that they don't.”

“There's no fire-escape and it's too far up for anything to come in from the street.” Average examined the walls with attention and returned to the big keyhole, through which he peeped.

“Do you ever chew gum?” he asked suddenly.

The Chemist stared at him. “It isn't a habit of mine to,” he said.

“But you wouldn't have any objection to my sending for some, in satisfaction of a sudden irresistible craving?”

“Any particular brand? I'll phone the corner drug store.”

“Any sort will suit, thank you.”

When the gum arrived, Average Jones, after politely offering some to his host, chewed up a single stick thoroughly. This he rolled out to an extremely tenuous consistency and spread it deftly across the unused keyhole, which it completely though thinly, veiled.

“Now, what's that for?” inquired the chemist, eying the improvised closure with some contempt.

“Don't know, exactly, yet,” replied the deviser, cheerfully. “But when queer and fatal things happen in a room and there's only one opening, it's just as well to keep your eye on that, no matter how small it is. Better still, perhaps, if you'd shift your office.”

The fat young chemist pushed his hair back, looked out of the window, and then turned to Average Jones. The rather flabby lines of his face had abruptly hardened over the firm contour below.

“No. I'm hanged if I will,” he said simply.

An amiable grin overspread Average Jones' face.

“You've got more nerve than prudence,” he observed. “But I don't say you aren't right. Since you're going to stick to the ship, keep your eye on that gum. If it lets go its hold, wire me.”

“All right,” agreed young Mr. Dorr. “Whatever your little game is, I'll play it. Give me your address in case you leave town.”

“As I may do. I am going to hire a press-clipping bureau on special order to dig through the files of the local and neighboring city newspapers for recent items concerning dog-poisoning cases. If our unknown has devised a new method of canicide, it's quite possible he may have worked it somewhere else, too. Good-by, and if you can't be wise, be careful.”

Dog-poisoning seemed to Average Jones to have become a popular pastime in and around New York, judging from the succession of news items which poured in upon him from the clipping bureau. Several days were exhausted by false clues. Then one morning there arrived, among other data, an article from the Bridgeport Morning Delineator which caused the Ad-Visor to sit up with a jerk. It detailed the poisoning of several dogs under peculiar circumstances. Three hours later he was in the bustling Connecticut city. There he took carriage for the house of Mr. Curtis Fleming, whose valuable Great Dane dog had been the last victim.

Mr. Curtis Fleming revealed himself as an elderly, gentleman all grown to a point: pointed white nose, eyes that were pin-points of irascible gleam, and a most pointed manner of speech.

“Who are you?” he demanded rancidly, as his visitor was ushered in.

Average Jones recognized the type. He knew of but one way to deal with it.

“Jones!” he retorted with such astounding emphasis that the monosyllable fairly exploded in the other's face.

“Well, well, well,” said the elder man, his aspect suddenly mollified. “Don't bite me. What kind of a Jones are you, and what do you want of me?”

“Ordinary variety of Jones. I want to now about your dog.”

“Reporter?”

“No.”

“Glad of it. They're no good. Had my reporters on this case. Found nothing.”

“Your reporters?”

“I own the Bridgeport Delineator.”

“What about the dog?”

“Good boy!” approved the old martinet. “Sticks to his point. Dog was out walking with me day before yesterday. Crossing a vacant lot on next square. Chased a rat. Rat ran into a heap of old timber. Dog nosed around. Gave a yelp and came back to me. Had spasm. Died in fifteen minutes. And hang me, sir,” cried the old man, bringing his fist down on Average Jones' knee, “if I see how the poison got him, for he was muzzled to the snout, sir!”

“Muzzled? Then—er—why do, you—er—suggest poison?” drawled the young man.

“Fourth dog to go the same way in the last week.”

“All in this locality?”

“Yes, all on Golden Hill.”

“Any suspicions?”

“Suspicions? Certainly, young man, certainly. Look at this.”

Average Jones took the smutted newspaper proof which his host extended, and read:

“WARNING-Residents of the Golden Hill neighborhood are earnestly cautioned against unguarded handling of timber about woodpiles or outbuildings until further notice. Danger!”

“When was this published?”

“Wasn't published. Delineator refused it. Thought it was a case of insanity.”

“Who offered it?”

“Professor Moseley. Tenant of mine. Frame house on the next corner with old-fashioned conservatory.”

“How long ago?”

“About a week.”

“All the dogs you speak of died since then?”

“Yes.”

“Did he give any explanation of the advertisement?”

“No. Acted half-crazy when he brought it to the office, the business manager said. Wouldn't sign his name to the thing. Wouldn't say anything about it. Begged the manager to let him have the weather reports in advance, every day. The manager put the advertisement in type, decided not to it, and returned the money.”

“'Weather reports, eh?” Average Jones mused a moment. “How long was the ad to run?”

“Until the first hard frost.”

“Has there—er—been a—er—frost since?” drawled Average Jones.

“No.”

“Who is this Moseley?”

“Don't know much about him. Scientific experimenter of some kind, I believe. Very exclusive,” added Mr. Curtis Fleming, with a grin. “Never sociated with any of us neighbors. Rent on the nail, though. Insane, too, I think. Writes letters to himself with nothing in them.”

“How's that?” inquired Average Jones.

The other took an envelope from his pocket and handed it over. “It got enclosed by mistake with the copy for the advertisement. The handwriting on the envelope is his own. Look inside.”

A glance had shown Average Jones that the letter, had been mailed in New York on March twenty-fifth. He took out the enclosure. It was a small slip of paper. The date was stamped on with a rubber stamp. There was no writing of any kind. Near the center of the sheet were three dots. They seemed to have been made with red ink.

“You're sure the address is in Professor Moseley's writing?”

“I'd swear to it.”

“It doesn't follow that he mailed it to himself. In fact, I should judge that it was sent by someone who was particularly anxious not to have any specimen of his handwriting lying about for identification.

“Perhaps. What's your interest in all this, anyway my mysterious young friend?”

“Two dogs in New York poisoned in something the same way as yours.”

“Well, I've got my man. He confessed.”

“Confessed?” echoed Average Jones.

“Practically. I've kept the point of the story to the last. Professor Moseley committed suicide this morning.”

If Mr. Curtis Fleming had designed to make an impression on his visitor, his ambition was fulfilled. Average Jones got to his feet slowly, walked over to the window, returned, picked up the strange proof with its message of suggested peril, studied it, returned to the window, and stared out into the day.

“Cut his throat about nine o'clock this morning,” pursued the other. “Dead when they found him.”

“Do you mind not talking to me for a minute?” said Average Jones curtly.

“Told to hold my tongue in my own house by uninvited stripling,” cackled the other. “You' re a singular young man. Have it your own way.”

After a five minutes' silence the visitor turned from the window and spoke. “There has been a deadly danger loose about here for which Professor Moseley felt himself responsible. He has killed himself. Why?”

“Because I was on his trail,” declared Mr. Curtis Fleming. “Afraid to face me.”

“Nonsense. I believe some human being has been killed by this thing, whatever it may be, and that the horror of it drove Moseley to suicide.”

“Prove it.”

“Give me a morning paper.”

His host handed him the current issue of the Delineator.

Average Jones studied the local page.

“Where's Galvin's Alley?” he asked presently.

“Two short blocks from here.”

“In the Golden Hill section?”

“Yes.”

“Read that.”

Mr. Curtis Fleming took the paper. His eyes were directed to a paragraph telling of the death of an Italian child living in Galvin's Alley. Cause, convulsions.

“By Jove!” said he, somewhat awed. “You can reason, young man.”

“I've got to, reason a lot further, if I'm to get anywhere in this affair,” said Average Jones with conviction. “Do you care, to come to Galvin's Alley with me?”

Together they went down the hill to a poor little house, marked by white crepe. The occupants were Italians who spoke some English. They said that four-year-old Pietro had been playing around a woodpile the afternoon before, when he was taken sick and came home, staggering. The doctor could do nothing. The little one passed from spasm into spasm, and died in an hour.

“Was there a mark like a ring anywhere on the hand or face?” asked Average Jones.

The dead child's father looked surprised. That, he said, was what the strange gentleman who had come that very morning asked, a queer, bent little gentlemen, very bald and with big eye-glasses, who was kind, and wept with them and gave them money to bury the “bambino.”

“Moseley, by the Lord Harry!” exclaimed Mr. Curtis Fleming. “But what was the death-agent?”

Average Jones shook his head. “Too early to do more than guess. Will you take me to Professor Moseley's place?”

The old house stood four-square, with a patched-up conservatory on one wing. In the front room they found the recluse's body decently disposed, with an undertaker's assistant in charge. From the greenhouse came a subdued hissing.

“What's that?” asked Jones.

“Fumigating the conservatory. There was a note found near the body insisting on its being done. 'For safety,' it said, so I ordered it looked to.”

“You're in charge, then?”

“It's my house. And there are no relatives so far as I know. Come and look at his papers. You won't find much.”

In the old-fashioned desk was a heap of undecipherable matter, interspersed with dates, apparently bearing upon scientific experiments; a package of letters from the Denny Research Laboratories of St. Louis, mentioning enclosure of checks; and three self-addressed envelopes bearing New York postmarks, of dates respectively, March 12, March 14 and March 20. Each contained a date-stamped sheet of paper, similar to that which Mr. Curtis Fleming had shown to Average Jones. The one of earliest date bore two red dots; the second, three red dots, and the third, two. All the envelopes were endorsed in Professor Moseley's handwriting; the first with the one word “Filled.” The second writing was “Held for warmer weather.” The last was inscribed “One in poor condition.”

Of these Average Jones made careful note, as well as of the laboratory address. By this time the hissing of the fumigating apparatus had ceased. The two men went to the conservatory and gazed in upon a ruin of limp leaves and flaccid petals, killed by the powerful gases. Suddenly, with an exclamation of astonishment, the investigator stooped and lifted from the floor a marvel of ermine body and pale green wings. The moth, spreading nearly a foot, was quite dead.

“Here's the mate, sir,” said the fumigating expert, handing him another specimen, a trifle smaller. “The place was crowded with all kinds of pretty ones. All gone where the good bugs go now.”

Average Jones took the pair of moths to the desk, measured them and laid them carefully away in a drawer.

“The rest must wait,” he said. “I have to send a telegram.”

With the interested Mr. Curtis Fleming in attendance, he went to the telegraph office, where he wrote out a dispatch.

“Mr. A. V. R. Jones?” said the operator. “There's a message here for you.”

Average Jones took the leaflet and read:

“Found gum on floor this morning when I arrived. MALCOLM DORR.”

Then he recalled his own blank, tore it up, and substituted the following, which he ordered “rushed”:

MALCOLM DORR, STENGEL BUILDING, NEW YORY CITY:

“Leave office immediately. Do not return until it has been fumigated thoroughly. Imperative. A. V. R. JONES.”

“And now,” said Average Jones to Mr. Fleming, “I'm going back to New York. If any collectors come chasing to you for luna moths, don't deal with them. Refer them to me, please. Here is my card.”

“Your orders shall be obeyed,” said the older man, his beady eyes twinkling. “But why, in the name of all that's unheard of, should collectors come bothering me about luna moths?”

“Because of an announcement to this effect which will appear in the next number of the National Science Weekly, and in coming issues of the New York Evening Register.”

He handed out a rough draft of this advertisement:

“What about further danger here?” inquired Mr. Fleming, as Average Jones bade him good-by. “Would we better run that warning of poor Moseley's, after all?”

For reply Jones pointed out the window. A late season whirl of snow enveloped the streets.

“I see,” said the old man. “The frost. Well Mr. Mysterious Jones, I don't know what you're up to, but you've given me an interesting day. Let me know what comes of it.”

On the train back to New York, Average Jones Wrote two letters. One was to the Denny Research Laboratories in St. Louis, the other to the Department of Agriculture at Washington. On the following morning he went to Dorr's office. That young chemist was in a recalcitrant frame of mind.

“I've done about ten dollars' worth of fumigating and a hundred dollars' worth of damage,” he said, “and now, I'd like to have a Missouri sign. In other words, I want to be shown. What did some skunk want to kill my dogs for?”

“He didn't.”

“But they're dead, aren't they?”

“Accident.”

“What kind of an accident?”

“The kind in which the innocent bystander gets the worst of it. You're the one it was meant for.”

“Me?”

“Certainly. You'd probably have got it if the dog hadn't.”

The speaker examined the keyhole, then walked over to the radiator and looked over, under and through it minutely. “Nothing there,” he observed; and, after extending his examination to the windows, book-shelf and desk, added:

“I guess we might have spared the fumigation. However, the safest side is the best.”

“What is it? Some new game in projective germs?” demanded the chemist.

“Oh, disinfectants will kill other things besides germs,” returned Average Jones. “Luna moths, for instance. Wait a few days and I'll have some mail to show you on that subject. In the meantime, have a plumber solder up that keyhole so tight that nothing short of dynamite can get through it.”

Collectors of lepidoptera rose in shoals to the printed offer of luna moths measuring ten and eleven inches across the wings. Letters came in by, every mail, responding variously with fervor, suspicion, yearning eagerness, and bitter skepticism to Average Jones' advertisement. All of these he put aside, except such as bore a New York postmark. And each day he compared the new names signed to the New York letters with the directory of occupants of the Stengel Building. Less than a week after the luna moth advertisement appeared, Average Jones walked into Malcolm Dorr's office with a twinkle in his eye.

“Do you know a man named Marcus L. Ross?” he asked the chemist.

“Never heard of him.”

“Marcus L. Ross is interested, not only in luna moths, but in the rest of the Moseley collection. He writes from the Delamater Apartments, where he lives, to tell me so. Also he has an office in this building. Likewise he works frequently at night. Finally, he is one of the confidential lobbyists of the Paragon Pressed Meat Company. Do you see?”

“I begin,” replied young Mr. Dorr.

“It would be very easy for Mr. Ross, whose office is on the floor above, to stop at this door on his way, down-stairs after quitting work late at night when the elevator had stopped running and—let us say—peep through the keyhole.”

Malcolm Dorr got up and stretched himself slowly. The sharp, clean lines of his face suddenly stood out again under the creasy flesh.

“I don't know what you're going to do to Mr. Ross,” he said, “but I want to see him first.”

“I'm not going to do anything to him,” returned Average Jones, “because, in the first place, I suspect that he is far, far away, having noted, doubtless, the plugged keyhole and suffered a crisis of the nerves. It's strange how nervous your scientific murderer is. Anyway, Ross is only an agent. I'm going to aim higher.”

“As how?”

“Well, I expect to do three things. First, I expect to scare a peaceful but murderous trust multimillionaire almost out of his senses; second, I expect to dispatch a costly yacht to unknown seas; and third, I expect to raise the street selling price of the evening 'yellow' journals, temporarily, about one thousand per cent. What's the answer? The answer is 'Buy to-night's papers.'”

New York, that afternoon, saw something new in advertising. That it really was advertising was shown by the “Adv.” sign, large and plain, in both the papers which carried it. The favored journals were the only two which indulged in “fudge” editions; that is, editions with glaring red-typed inserts of “special” news. On the front page of each, stretching narrowly across three columns, was a device showing a tiny mapped outline in black marked Bridgeport, Conn., and a large skeleton draft of Manhattan Island showing the principal streets. From the Connecticut city downward ran a line of dots in red. The dots entered New York from the north, passed down Fourth Avenue to the south side of Union Square, turned west and terminated. Beneath this map was the legend, also in red:

WATCH THE LINE ADVANCE IN LATER EDITIONS

It was the first time in the records of journalism that the “fudge” device had been used in advertising.

Great was the rejoicing of the “newsies” when public curiosity made a “run” upon these papers. Greater it grew when the “afternoon edition” appeared, and with their keen business instinct, the urchins saw that they could run the price upward, which they promptly did, in some cases even to a nickel. This edition carried the same “fudge” advertisement, but now the red dots crossed over to Fifth Avenue and turned northward as far as Twenty-third Street. The inscription was:

UPWARD AND ONWARD SEE NEXT EXTRA

For the “Night Extra” people paid five, ten, even fifteen cents. Rumor ran wild. Other papers, even, look the matter up as news, and commented upon the meaning of the extraordinary advertisement. This time, the red-dotted line went as far up Fifth Ave title as Fiftieth Street. And the legend was ominous:

WHEN I TURN, I STRIKE

That was all that evening. The dotted line did not turn.

Keen as newspaper conjecture is, it failed to connect the “red-line maps,” with the fame of which the city was raging, with an item of shipping news printed in the evening papers of the following day:

And not until the following morning did the papers announce that President Colwell, of the Canned Meat Trust, having been ordered by his physician on a long sea voyage to refurbish his depleted nerves, after closing his house on West Fifty-first Street, had sailed in his own yacht. The same issue carried a few lines about the “freak ads.” which had so sensationally blazed and so suddenly waned from the “yellows.” The opinion was offered that they represented the exploitation of some new brand of whisky which would announce itself later. But that announcement never came, and President Colwell sailed to far seas, and Mr. Curtis Fleming came to New York, keen for explanations, for he, too, had seen the “fudge” and marveled. Hence, Average Jones had him, together with young Mr. Dorr, at a private room luncheon at the Cosmic Club, where he offered an explanation and elucidation.

“The whole affair,” he said, “was a problem in the connecting up of loose ends. At the New York terminus we had two deaths in the office of a man with powerful and subtle enemies, that office being practically sealed against intrusion except for a very large keyhole. Some deadly thing is introduced through that keyhole; so much is practically proven by the breaking out of the chewing gum with which I coated it. Probably the scheme was carried out in the evening when the building was nearly deserted. The killing influence reaches a corner far out of the direct line of the keyhole. Being near the radiator, that corner represents the attraction of warmth. Therefore, the invading force was some sentient creature.”

Dorr shuddered. “Some kind of venomous snake,” he surmised.

“Not a bad guess. But a snake, however small, would have been instantly noticed by the dogs. Now, let's look at the Bridgeport end. Here, again, we have a deadly influence loosed; this time by accident. A scientific experimentalist is the innocent cause of the disaster. Here, too, the peril is somewhat dependent upon warmth, since we know, from Professor Moseley's agonized eagerness for a frost, that cold weather would have put an end to it. The cold weather fails to come. Dogs are killed. Finally a child falls victim, and on that child is found a circular mark, similar to the mark on Mr. Dorr's dog's lip. You see the striking points of analogy?”

“Do you mean us to believe poor old Moseley a cold-blooded murderer?” demanded Mr. Curtis Fleming.

“Far from it. At worst an unhappy victim of his own carelessness in loosing a peril upon his neighborhood. You're forgetting a connecting link; the secretive red-dot communications from New York City addressed by Moseley to himself on behalf of some customer who ordered simply by a code of ink dots. He was the man I had to find. The giant luna moths helped to do it.”

“I don't see where they come in at all,” declared Dorr bluntly. “A moth a foot wide couldn't crawl through a keyhole.”

“No; nor do any damage if it did. The luna is as harmless as it is lovely. In this case the moths weren't active agents. They were important only as clues—and bait. Their enormous size showed Professor Moseley's line of work; the selective breeding of certain forms of life to two or three times the normal proportions. Very well; I had to ascertain some creature which, if magnified several times, would be deadly, and which would still be capable of entering a large keyhole. Having determined that—”

“You found what it was?” cried Dorr.

“One moment. Having determined that, I had still to get in touch with Professor Moseley's mysterious New York correspondent. I figured that he must be interested in Professor Moseley's particular branch of research or he never could have devised his murderous scheme. So I constructed the luna moth advertisement to draw him, and when I got a reply from Mr. Ross, who is a fellow-tenant of Mr. Dorr's, the chain was complete. Now, you see where the luna moths were useful. If I had advertised, instead of them, the lathrodectus, he might have suspected and refrained from answering.”

“What's the lathrodectus?” demanded both the hearers at once.

For answer Average Jones took a letter from his pocket and read:

BUREAU OF ENTOMOLOGY, U. S. DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C., April 7

MR. A. V. R. JONES,

Astor Court Temple, New York City.

DEAR Sir,

Replying to your letter of inquiry, the only insect answering your specifications is a small spider Lathrodectus mactans, sometimes popularly called the Red Dot, from a bright red mark upon the back. Rare cases are known where death has been caused by the bite of this insect. Fortunately its fangs are so weak that they can penetrate only very tender skin, otherwise death from its bite would be more common, as the venom, drop for drop, is perhaps the most virulent known to science.

This Bureau knows nothing of any experiments in breeding the Lathrodectus for size. Your surmise that specimens of two or three times the normal size would be dangerous to life is undoubtedly correct, and selected breeding to that end should be conducted only under adequate scientific safeguards. A Lathrodectus mactans with fangs large enough to penetrate the skin of the hand, and a double or triple supply of venom, would be, perhaps, more deadly than a cobra.

The symptoms of poisoning by this species are spasms, similar to those of trismus, and agonizing general pains. There are no local symptoms, except, in some cases, a circle of small pustules about the bitten spot.

Commercially, the Lathrodectus has value, in that the poison is used in certain affections of the heart. For details, I would refer you to the Denny Laboratories of St. Louis, Mo., which are purchasers of the venom.

The species is very susceptible to cold, and would hardly survive a severe frost. It frequents woodpiles and outhouses. Yours truly,

L. O. HOWARD, Chief of Bureau.

“Then Ross was sneaking down here at night and putting the spiders which he had got from Professor Moseley through my keyhole, in the hope that sooner or later one of them would get me,” said Dorr.

“A very reasonable expectation, too. Vide, the dogs,” returned Average Jones.

“And now,” said Mr. Curtis Fleming, “will some one kindly explain to me what this Ross fiend had against our friend, Mr. Dorr?”

“Nothing,” replied Average Jones.

“Nothing? Was he coursing with spiders merely for sport?”

“Oh, no. You see Mr. Dorr was interfering with the machinery of one of our ruling institutions, the Canned Meat Trust. He possessed information which would have indicted all the officials. Therefore it was desirable—even essential—that he should be removed from the pathway of progress.”

“Nonsense! Socialistic nonsense!” snapped Mr. Curtis Fleming. “Trusts may be unprincipled, but they don't commit individual crimes.”

“Don't they?” returned Average Jones, smiling amiably at his own boot-tip. “Did you ever hear of Mr. Adel Meyer's little corset steel which he invented to stick in the customs scales and rob the government for the profit of his Syrup Trust? Or of the individual oil refineries which mysteriously disappeared in fire and smoke at a time when they became annoying to the Combination Oil Trust? Or of the Traction Trust's two plots to murder Prosecutor Henry in San Francisco? I'm just mentioning a few cases from memory. Why, when a criminal trust faces only loss it will commit forgery, theft or arson. When it faces jail, it will commit murder just as determinedly. Self-defense, you know. As for the case of Mr. Dorr—” and he proceeded to detail the various attempts on the young chemist's life.

“But why so roundabout a method?” asked Dorr skeptically.

“Well, they tried the ordinary methods of murder on you through agents. That didn't work. It was up to the Trust to put one of its own confidential men on it. Ross is an amateur entomologist. He devised a means that looked to be pretty safe and, in the long run, sure.”

“And would have been but for your skill, young Jones,” declared Mr. Curtis Fleming, with emphasis.

“Don't forget the fortunate coincidences,” replied Average Jones modestly. “They're about half of it. In fact, detective work, for all that is said on the other side, is mostly the ability to recognize and connect coincidences. The coincidence of the escape of the Red Dots from Professor Moseley's breeding cages; the coincidence of the death of the dogs on Golden Hill, followed by the death of the child; the coincidence of poor Moseley's having left the red dot letters on the desk instead of destroying them; the coincidence of Dorr's dogs being bitten, when it might easily have been himself had he gone to turn on the radiator and disturbed the savage little spider—“'

“And the chief coincidence of your having become interested in the advertisement which Judge Elverson had me insert, really more to scare off further attempts than anything else,” put in Dorr. “What became of the spiders that were slipped through my keyhole, anyway?”

“Two of them, as you know, were probably killed by the dogs. The others may well have died of cold. At night when the heat was off and the windows open. The cleaning woman wouldn't have been likely to notice them when she swept the bodies out. And, sooner or later, if Ross had continued to insert Red Dots through the keyhole one of them would have bitten you, Dorr, and the Canned Meat Trust would have gone on its way rejoicing.”

“Well, you've certainly saved my life,” declared Dorr, “and it's a case of sheer force of reasoning.”

Average Jones shook his head. “You might give some of the credit to Providence,” he said. “Just one little event would have meant the saving of the Italian child, and of Professor Moseley, and the death of yourself, instead of the other way around.”

“And that event?” asked Mr. Curtis Fleming.

“Five degrees of frost in Bridgeport,” replied Average Jones.