With this astounding revelation the Bishop murder case entered its final and most terrible phase. Heath had been informed of Vance's discovery; and it was arranged that we should meet in the District Attorney's office early the following day for a counsel of war.

    Markham, when he took leave of us that night, was more troubled and despondent than I had ever seen him.

    "I don't know what can be done," he said hopelessly. "There's no legal evidence against the man. But we may be able to devise some course of action that will give us the upper hand. . . . I never believed in torture, but I almost wish we had access today to the thumbscrew and the rack."

    Vance and I arrived at his office a few minutes after nine the next morning. Swacker intercepted us and asked us to wait in the reception room for a little while. Markham, he explained, was engaged for the moment. We had no more than seated ourselves when Heath appeared, grim, pugnacious and sullen.

    "I gotta hand it to you, Mr. Vance," he proclaimed. "You sure got a line on the situation. But what good it's going to do us I don't see. We can't arrest a guy because his name's in a book."

    "We may be able to force the issue some way," Vance rejoined. "In any event, we now know where we stand."

    Ten minutes later Swacker beckoned to us and indicated that Markham was free.

    "Sorry to have kept you waiting," Markham apologized. "I had an unexpected visitor." His voice had a despairing ring. "More trouble. And, curiously enough, it's connected with the very section of Riverside Park where Drukker was killed. However, there's nothing I can do about it. . . ." He drew some papers before him. "Now to business."

    "What's the new trouble in Riverside Park?" asked Vance casually.

    Markham frowned.

    "Nothing that need bother us now. A kidnapping, in all likelihood. There's a brief account of it in the morning papers, in case you're interested. . . ."

    "I detest reading the papers." Vance spoke blandly, but with an insistence that puzzled me. "What happened?"

    Markham drew a deep breath of impatience.

    "A child disappeared from the playground yesterday after talking with an unknown man. Her father came here to solicit my help. But it's a job for the Bureau of Missing Persons; and I told him so.—Now, if your curiosity is appeased—"

    "Oh, but it isn't," persisted Vance. "I simply must hear the details. That section of the park fascinates me strangely."

    Markham shot him a questioning glance through lowered lids.

    "Very well," he acquiesced. "A five-year-old girl, named Madeleine Moffat, was playing with a group of children at about half past five last evening. She crawled up on a high mound near the retaining wall, and a little later, when her governess went to get her, thinking she had descended the other side, the child was nowhere to be found. The only suggestive fact is that two of the other children say they saw a man talking to her shortly before she disappeared; but, of course, they can give no description of him. The police were notified, and are investigating. And that's all there is to the case so far."

    "'Madeleine.'" Vance repeated the name musingly. "I say, Markham; do you know if this child knew Drukker?"

    "Yes!" Markham sat up a little straighter. "Her father mentioned that she often went to parties at his house. . . ."

    "I've seen the child." Vance rose and stood, hands in pockets, gazing down at the floor. "An adorable little creature . . . golden curls. She brought a handful of flowers for Drukker the morning of his funeral. . . . And now she has disappeared after having been seen talking with a strange man. . . ."

    "What's going on in your mind?" demanded Markham sharply.

    Vance appeared not to have heard the question.

    "Why should her father appeal to you?"

    "I've known Moffat slightly for years—he was at one time connected with the city administration. He's frantic—grasping at every straw. The proximity of the affair to the Bishop murders has made him morbidly apprehensive. . . . But see here, Vance; we didn't come here to discuss the Moffat child's disappearance. . . ."

    Vance lifted his head: there was a look of startled horror on his face.

    "Don't speak—oh, don't speak. . . ." He began pacing up and down, while Markham and Heath watched him in mute amazement. "Yes—yes; that would be it," he murmured to himself. "The time is right . . . it all fits. . . ."

    He swung about, and going to Markham seized his arm.

    "Come—quickly! It's our only chance—we can't wait another minute." He fairly dragged Markham to his feet and led him toward the door. "I've been fearing something like this all week—"

    Markham wrenched his arm free from the other's grip.

    "I won't move from this office, Vance, until you explain."

    "It's another act in the play—the last act! Oh, take my word for it." There was a look in Vance's eyes I had never seen before. "It's 'Little Miss Muffet' now. The name isn't identical, but that doesn't matter. It's near enough for the Bishop's jest; he'll explain it all to the press. He probably beckoned the child to the tuffet, and sat down beside her. And now she's gone—frightened away. . . ."

    Markham moved forward in a sort of daze; and Heath, his eyes bulging, leapt to the door. I have often wondered what went on in their minds during those few seconds of Vance's importunate urgings. Did they believe in his interpretation of the episode? Or were they merely afraid not to investigate, in view of the remote possibility that another hideous joke had been perpetrated by the Bishop? Whatever their convictions or doubts, they accepted the situation as Vance saw it; and a moment later we were in the hall, hastening toward the elevator. At Vance's suggestion we picked up Detective Tracy from the branch office of the Detective Bureau in the Criminal Courts Building.

    "This affair is serious," he explained. "Anything may happen."

    We emerged through the Franklin-Street entrance, and in a few minutes were on our way up-town in the District Attorney's car, breaking speed regulations and ignoring traffic signals. Scarcely a word was spoken on that momentous ride; but as we swung through the tortuous roads of Central Park Vance said:

    "I may be wrong, but we will have to risk it. If we wait to see whether the papers get a note, it'll be too late. We're not supposed to know yet; and that's our one chance. . . ."

    "What do you expect to find?" Markham's tone was husky and a little uncertain.

    Vance shook his head despondently.

    "Oh, I don't know. But it'll be something devilish."

    When the car drew up with a lurch in front of the Dillard house Vance leapt out and ran up the steps ahead of us. Pyne answered his insistent ring.

    "Where's Mr. Arnesson?" he demanded.

    "At the university, sir," the old butler replied; and I imagined there was fright in his eyes. "But he'll be home for an early lunch."

    "Then take us at once to Professor Dillard."

    "I'm sorry, sir," Pyne told him; "but the professor is also out. He went to the Public Library—"

    "Are you alone here?"

    "Yes, sir. Beedle's gone to market."

    "So much the better." Vance took hold of the butler and turned him toward the rear stairs. "We're going to search the house, Pyne. You lead the way."

    Markham came forward.

    "But, Vance, we can't do that!"

    Vance wheeled round.

    "I'm not interested in what you can do or can't do. I'm going to search this house. . . . Sergeant, are you with me?" There was a strange look on his face.

    "You bet your sweet life!" (I never liked Heath as much as at that moment.)

    The search was begun in the basement. Every hallway, every closet, every cupboard and waste space was inspected. Pyne, completely cowed by Heath's vindictiveness, acted as guide. He brought keys and opened doors for us, and even suggested places we might otherwise have overlooked. The Sergeant had thrown himself into the hunt with energy, though I am sure he had only a vague idea as to its object. Markham followed us disapprovingly; but he, too, had been caught in the sweep of Vance's dynamic purposefulness; and he must have realized that Vance had some tremendous justification for his rash conduct.

    Gradually we worked our way upward through the house. The library and Arnesson's room were gone over carefully. Belle Dillard's apartment was scrutinized, and close attention was given to the unused rooms on the third floor. Even the servants' quarters on the fourth floor were overhauled. But nothing suspicious was discovered. Though Vance suppressed his eagerness I could tell what a nervous strain he was under by the tireless haste with which he pushed the search.

    Eventually we came to a locked door at the rear of the upper hall.

    "Where does that lead?" Vance asked Pyne.

    "To a little attic room, sir. But it's never used—"

    "Unlock it."

    The man fumbled for several moments with his bunch of keys.

    "I don't seem to find the key, sir. It's supposed to be here. . . ."

    "When did you have it last?"

    "I couldn't say, sir. To my knowledge no one's been in the attic for years."

    Vance stepped back and crouched.

    "Stand aside, Pyne."

    When the butler had moved out of the way Vance hurled himself against the door with terrific force. There was a creaking and straining of wood; but the lock held.

    Markham rushed forward and caught him round the shoulders.

    "Are you mad!" he exclaimed. "You're breaking the law."

    "The law!" There was scathing irony in Vance's retort. "We're dealing with a monster who sneers at all law. You may coddle him if you care to, but I'm going to search that attic if it means spending the rest of my life in jail.—Sergeant, open that door!"

    Again I experienced a thrill of liking for Heath. Without a moment's hesitation he poised himself on his toes and sent his shoulders crashing against the door's panel just above the knob. There was a splintering of wood as the lock's bolt tore through the moulding. The door swung inward.

    Vance, freeing himself from Markham's hold, ran stumbling up the steps with the rest of us at his heels. There was no light in the attic, and we paused for a moment at the head of the stairs to accustom our eyes to the darkness. Then Vance struck a match and, groping forward, sent up the window shade with a clatter. The sunlight poured in, revealing a small room, scarcely ten feet square, cluttered with all manner of discarded odds and ends. The atmosphere was heavy and stifling, and a thick coating of dust lay over everything.

    Vance looked quickly about him, and an expression of disappointment came over his face.

    "This is the only place left," he remarked, with the calmness of desperation.

    After a more careful scrutiny of the room, he stepped to the corner by the little window and peered down at a battered suit-case which lay on its side against the wall. I noticed that it was unlatched and that its straps hung free. Leaning over he threw the cover back.

    "Ah! Here, at least, is something for you, Markham."

    We crowded about him. In the suit-case was an old Corona typewriter. A sheet of paper was in the carriage; and on it had already been typed, in pale-blue élite characters, the two lines:

    Little Miss Muffet

    Sat on a tuffet

    At this point the typist had evidently been interrupted, or for some other reason had not completed the Mother-Goose rhyme.

    "The new Bishop note for the press," observed Vance. Then reaching into the suit-case he lifted out a pile of blank paper and envelopes. At the bottom, beside the machine, lay a red-leather note-book with thin yellow leaves. He handed it to Markham with the terse announcement:

    "Drukker's calculations on the quantum theory."

    But there was still a look of defeat in his eyes; and again he began inspecting the room. Presently he went to an old dressing-table which stood against the wall opposite to the window. As he bent over to peer behind it he suddenly drew back and, lifting his head, sniffed several times. At the same moment he caught sight of something on the floor at his feet, and kicked it toward the centre of the room. We looked down at it with astonishment. It was a gas-mask of the kind used by chemists.

    "Stand back, you chaps!" he ordered; and holding one hand to his nose and mouth he swung the dressing-table away from the wall. Directly behind it was a small cupboard door about three feet high, set into the wall. He wrenched it open and looked inside, then slammed it shut immediately.

    Brief as was my view of the interior of the cupboard, I was able to glimpse its contents clearly. It was fitted with two shelves. On the lower one were several books lying open. On the upper shelf stood an Erlenmeyer flask clamped to an iron support, a spirit-lamp, a condenser tube, a glass beaker, and two small bottles.

    Vance turned and gave us a despairing look.

    "We may as well go: there's nothing more here."

    We returned to the drawing-room, leaving Tracy to guard the door to the attic.

    "Perhaps, after all, you were justified in your search," acknowledged Markham, studying Vance gravely. "I don't like such methods, however. If we hadn't found the typewriter—"

    "Oh, that!" Vance, preoccupied and restless, went to the window overlooking the archery range. "I wasn't hunting for the typewriter—or the note-book, either. What do they matter?" His chin fell forward on his breast, and his eyes closed in a kind of lethargy of defeat. "Everything's gone wrong—my logic has failed. We're too late."

    "I don't pretend to know what you're grumbling about," said Markham. "But at least you've supplied me evidence of a sort. I'll now be able to arrest Arnesson when he returns from the university."

    "Yes, yes; of course. But I wasn't thinking of Arnesson, or the arrest of the culprit, or the triumph of the District Attorney's office. I was hoping—"

    He broke off and stiffened.

    "We're not too late! I didn't think far enough. . . ." He went swiftly to the archway. "It's the Drukker house we must search. . . . Hurry!" He was already half-running down the hall, Heath behind him, and Markham and I bringing up the rear.

    We followed him down the rear stairs, across the archery-room, and out on the range. We did not know, and I doubt if any of us even guessed, what was in his mind; but some of his inner excitation had been communicated to us, and we realized that only a vital urgency could have shaken him so completely out of his usual attitude of disinterest and calm.

    When we came to the screen-porch of the Drukker house he reached through the broken wire-netting and released the catch. The kitchen door, to my astonishment, was unlocked; but Vance seemed to expect this, for he unhesitatingly turned the knob and threw it open.

    "Wait!" he directed, pausing in the little rear hallway. "There's no need to search the entire house. The most likely place. . . . Yes! Come along . . . up-stairs . . . somewhere in the centre of the house . . . a closet most likely . . . where no one could hear. . . ." As he spoke he led the way up the rear stairs, past Mrs. Drukker's room and the study, and thence to the third floor. There were but two doors on this upper hall—one at the extreme end, and a smaller door set midway in the right wall.

    Vance went straight to the latter. There was a key protruding from the lock, and, turning it, he drew open the door. Only a shadowy blackness met our eyes. Vance was on his knees in a second, groping inside.

    "Quick, Sergeant. Your flash-light."

    Almost before he had uttered the words a luminous circle fell on the floor of the closet. What I saw sent a chill of horror over me. A choked exclamation burst from Markham; and a soft whistle told me that Heath too was appalled by the sight. Before us on the floor, in a limp, silent heap, lay the little girl who had brought flowers to her broken Humpty Dumpty on the morning of his funeral. Her golden hair was dishevelled; her face was deathly pale, and there were streaks down her cheeks where the futile tears had welled forth and dried.

    Vance bent over and put his ear to her heart. Then he gathered her tenderly in his arms.

    "Poor little Miss Muffet," he whispered, and rising went toward the front stairs. Heath preceded him, flashing his light all the way so there would be no chance of his stumbling. In the main lower hall he paused.

    "Unbolt the door, Sergeant."

    Heath obeyed with alacrity, and Vance stepped out on the sidewalk.

    "Go to the Dillards' and wait for me there," he flung back over his shoulder. And with the child clasped closely to his breast he started diagonally across 76th Street to a house on which I could make out a doctor's brass name-plate.