When the doctor had straightened Mrs. Drukker's body on the bed and covered it with a sheet, we returned down-stairs. Barstead took his departure at once after promising to send the death certificate to the Sergeant within an hour.

    "It's scientifically correct to talk of natural death from shock," said Vance, when we were alone; "but our immediate problem, d' ye see, is to ascertain the cause of that sudden shock. Obviously it's connected with Drukker's death. Now, I wonder. . . ."

    Turning impulsively, he entered the drawing-room. Mrs. Menzel was sitting where we had left her, in an attitude of horrified expectancy. Vance went to her and said kindly:

    "Your mistress died of heart failure during the night. And it's much better that she should not have outlived her son."

    "Gott geb' ihr die ewige Ruh'!" the woman murmured piously. "Ja, it is best. . . ."

    "The end came at about ten last night.—Were you awake at that time, Mrs. Menzel?"

    "All night I was awake." She spoke in a low, awed voice.

    Vance contemplated her with eyes half shut.

    "Tell us what you heard?"

    "Somebody came here last night!"

    "Yes, some one came at about ten o'clock—by the front door. Did you hear him enter?"

    "No; but after I had gone to bed I heard voices in Mr. Drukker's room."

    "Was it unusual to hear voices in his room at ten o'clock at night?"

    "But it wasn't him! He had a high voice, and this one was low and gruff." The woman looked up in bewildered fright. "And the other voice was Mrs. Drukker's . . . and she never went in Mr. Drukker's room at night!"

    "How could you hear so plainly with your door shut?"

    "My room is right over Mr. Drukker's," she explained. "And I was worried—what with all these awful things going on; so I got up and listened at the top of the steps."

    "I can't blame you," said Vance. "What did you hear?"

    "At first it was like as though the mistress was moaning, but right away she began to laugh, and then the man spoke angry-like. But pretty soon I heard him laugh, too. After that it sounded like the poor lady was praying—I could hear her saying 'Oh, God—oh, God!' Then the man talked some more—very quiet and low. . . . And in a little while it seemed like the mistress was—reciting—a poem. . . ."

    "Would you recognize the poem if you heard it again? . . . Was it

    Humpty Dumpty sat on a wall;

    Humpty Dumpty had a great fall. . . ."

        

    "Bei Gott, das ist's! It sounded just like that!" A new horror came into the woman's expression. "And Mr. Drukker fell from the wall last night. . . ."

    "Did you hear anything else, Mrs. Menzel?" Vance's matter-of-fact voice interrupted her confused correlation of Drukker's death to the verse she had heard.

    Slowly she shook her head.

    "No. Everything was quiet after that."

    "Did you hear any one leave Mr. Drukker's room?"

    She gave Vance a panic-stricken nod.

    "A few minutes later some one opened and shut the door, very soft; and I heard steps moving down the hall in the dark. Then the stairs creaked, and pretty soon the front door shut."

    "What did you do after that?"

    "I listened a little while, and then I went back to bed. But I couldn't sleep. . . ."

    "It's all over now, Mrs. Menzel," Vance told her comfortingly. "There's nothing for you to fear.—You'd best go to your room and wait till we need you."

    Reluctantly the woman went up-stairs.

    "I think now," said Vance, "we can make a pretty close guess as to what happened here last night. The murderer took Drukker's key and let himself in by the front door. He knew Mrs. Drukker's quarters were at the rear, and he no doubt counted on accomplishing his business in Drukker's room and departing as he had come. But Mrs. Drukker heard him. It may be she associated him with 'the little man' who had left the black bishop at her door, and feared that her son was in danger. At any rate, she went at once to Drukker's room. The door may have been slightly open, and I think she saw the intruder and recognized him. Startled and apprehensive, she stepped inside and asked him why he was there. He may have answered that he had come to inform her of Drukker's death—which would account for her moans and her hysterical laughter. But that was only a prelimin'ry on his part—a play for time. He was devising some means of meeting the situation—he was planning how he would kill her! Oh, there can be no doubt of that. He couldn't afford to let her leave that room alive. Maybe he told her so in as many words—he spoke 'angry-like,' you recall. And then he laughed. He was torturing her now—perhaps telling her the whole truth in a burst of insane egoism; and she could say only 'Oh God—oh God!' He explained how he had pushed Drukker over the wall. And did he mention Humpty Dumpty? I think he did; for what more appreciative audience could he have had for his monstrous jest than the victim's own mother? That last revelation proved too much for her hypersensitive brain. She repeated the nursery rhyme in a spell of horror; and then the accumulated shock dilated her heart. She fell across the bed, and the murderer was saved the necessity of sealing her lips with his own hands. He saw what had happened, and went quietly away."

    Markham took a turn up and down the room.

    "The least comprehensible part of last night's tragedy," he said, "is why this man should have come here after Drukker's death."

    Vance was smoking thoughtfully.

    "We'd better ask Arnesson to help us explain that point. Maybe he can throw some light on it."

    "Yeh, maybe he can," chimed in Heath. Then after rolling his cigar between his lips for a moment, he added sulkily: "There's several people around here, I'm thinking, that could do some high-class explaining."

    Markham halted before the Sergeant.

    "The first thing we'd better do is to find out what your men know about the movements of the various persons hereabouts last night. Suppose you bring them here and let me question them.—How many were there, by the way?—and what were their posts?"

    The Sergeant had risen, alert and energetic.

    "There were three, sir, besides Guilfoyle. Emery was set to tail Pardee; Snitkin was stationed at the Drive and 75th Street to watch the Dillard house; and Hennessey was posted on 75th Street up near West End Avenue.—They're all waiting down at the place where Drukker was found. I'll get 'em up here     pronto."

    He disappeared through the front door, and in less than five minutes returned with the three detectives. I recognized them all, for each had worked on one or more of the cases in which Vance had figured.[26] Markham questioned Snitkin first as the one most likely to have information bearing directly on the previous night's affair. The following points were brought out by his testimony:

    Pardee had emerged from his house at 6.30 and gone straight to the Dillards'.

    At 8.30 Belle Dillard, in an evening gown, had got into a taxi and been driven up West End Avenue. (Arnesson had come out of the house with her and helped her into the taxicab, but had immediately returned indoors.)

    At 9.15 Professor Dillard and Drukker had left the Dillard house and walked slowly toward Riverside Drive. They had crossed the Drive at 74th Street, and turned up the bridle path.

    At 9.30 Pardee had come out of the Dillard house, walked down to the Drive, and turned up-town.

    At a little after 10.00 Professor Dillard had returned to his house alone, recrossing the Drive at 74th Street.

    At 10.20 Pardee had returned home, coming from the same direction he had taken when going out.

    Belle Dillard had been brought home at 12.30 in a limousine filled with young people.

    Hennessey was interrogated next; but his evidence merely substantiated Snitkin's. No one had approached the Dillard house from the direction of West End Avenue; and nothing of a suspicious nature had happened.

    Markham then turned his attention to Emery, who reported that, according to Santos whom he had relieved at six, Pardee had spent the early part of the afternoon at the Manhattan Chess Club and had returned home at about four o'clock.

    "Then, like Snitkin and Hennessey said," Emery continued, "he went to the Dillards' at half past six, and stayed till half past nine. When he came out I followed, keeping half a block or so behind him. He walked up the Drive to 79th Street, crossed to the upper park, and walked round the big grass bowl, past the rocks, and on up toward the Yacht Club. . . ."

    "Did he take the path where Sprigg was shot?" Vance asked.

    "He had to. There ain't any other path up that way unless you walk along the Drive."

    "How far did he go?"

    "The fact is, he stopped right about where Sprigg was bumped off. Then he came back the same way he'd gone and turned into the little park with the playground on the south side of 79th Street. He went slowly down the walk under the trees along the bridle path; and as he passed along the top of the wall under the drinking fountain, who should he run into but the old man and the hunchback, resting up against the ledge and talking. . . ."

    "You say he met Professor Dillard and Drukker at the very spot where Drukker fell over the wall?" Markham leaned forward hopefully.

    "Yes, sir. Pardee stopped to visit with them; and I naturally kept on going. As I passed 'em I heard the hunchback say: 'Why ain't you practising chess this evening?' And it sounded to me like he was sore at Pardee for stopping, and was hinting that he wasn't wanted. Anyhow, I ambled along the wall till I got to 74th Street where there was a couple of trees to hide under. . . ."

    "How well could you see Pardee and Drukker after you'd reached 74th Street?" interrupted Markham.

    "Well, sir, to tell you the truth, I couldn't see 'em at all. It was getting pretty misty about that time, and there isn't any lamp-post at that part of the walk where they were confabulating. But I figured Pardee would be along pretty soon, so I waited for him."

    "This must have been well on toward ten o'clock."

    "About a quarter of, I should say, sir."

    "Were there any people on the walk at that time?"

    "I didn't see anybody. The fog musta driven 'em indoors—it wasn't no warm balmy evening. And it was on account of there being nobody around that I went as far ahead as I did. Pardee's nobody's fool, and I'd already caught him looking at me once or twice as though he suspected I was tailing him."

    "How long was it before you picked him up again?"

    Emery shifted his position.

    "My figuring wasn't so good last night," he confessed, with a weak grin. "Pardee musta gone back the way he came and recrossed the Drive at 79th Street; for a half-hour or so later I saw him heading home in front of the apartment-house light on the corner of 75th Street."

    "But," interposed Vance; "if you were at the 74th Street entrance to the park until a quarter past ten you must have seen Professor Dillard pass you. He returned home about ten o'clock by that route."

    "Sure, I saw him. I'd been waiting for Pardee about twenty minutes when the professor came strolling along all alone, crossed the Drive, and went home. I naturally thought Pardee and the hunchback were still gabbing,—that's why I took it easy and didn't go back to check up."

    "Then, as I understand, about fifteen minutes after Professor Dillard passed you, you saw Pardee returning home from the opposite direction along the Drive."

    "That's right, sir. And, of course, I took up my post again on 75th Street."

    "You realize, Emery," said Markham gravely, "that it was during the time you waited at 74th Street that Drukker fell over the wall."

    "Yes, sir. But you're not blaming me, are you? Watching a man on a foggy night on an open path when there ain't anybody around to screen you, is no easy job. You gotta take a few chances and do a little figuring if you don't want to get spotted."

    "I realize your difficulty," Markham told him; "and I'm not criticizing you."

    The Sergeant dismissed the three detectives gruffly. He was obviously dissatisfied with their reports.

    "The farther we go," he complained, "the more gummed up this case gets."

    "Sursum corda, Sergeant," Vance exhorted him. "Let not dark despair o'ercome you. When we have Pardee's and the Professor's testimony as to what took place while Emery was watchfully waiting beneath the trees at 74th Street, we may be able to fit some very interestin' bits together."

    As he spoke Belle Dillard entered the front hall from the rear of the house. She saw us in the drawing-room and came in at once.

    "Where's Lady Mae?" she asked in a troubled voice. "I was here an hour ago, and Grete told me she was out. And she's not in her room now."

    Vance rose and gave her his chair.

    "Mrs. Drukker died last night of heart failure. When you were here earlier Mrs. Menzel was afraid to let you go up-stairs."

    The girl sat very quiet for some time. Presently the tears welled to her eyes.

    "Perhaps she heard of Adolph's terrible accident."

    "Possibly. But it's not quite clear what happened here last night. Doctor Barstead thinks Mrs. Drukker died at about ten o'clock."

    "Almost the same time Adolph died," she murmured. "It seems too terrible. . . . Pyne told me of the accident when I came down to breakfast this morning,—every one in the quarter was talking about it,—and I came over at once to be with Lady Mae. But Grete said she had gone out, and I didn't know what to think. There's something very strange about Adolph's death. . . ."

    "What do you mean by that, Miss Dillard?" Vance stood by the window watching her covertly.

    "I—don't know—what I mean," she answered brokenly. "But only yesterday afternoon Lady Mae spoke to me about Adolph and the—wall. . . ."

    "Oh, did she, now?" Vance's tone was more indolent than usual, but every nerve in his body was, I knew, vigilantly alert.

    "On my way to the tennis courts," the girl went on, in a low, hushed voice, "I walked with Lady Mae along the bridle path above the playground—she often went there to watch Adolph playing with the children,—and we stood for a long time leaning over the stone balustrade of the wall. A group of children were gathered around Adolph: he had a toy aeroplane and was showing them how to fly it. And the children seemed to regard him as one of themselves; they didn't look upon him as a grown-up. Lady Mae was very happy and proud about it. She watched him with shining eyes, and then she said to me: 'They're not afraid of him, Belle, because he's a hunchback. They call him Humpty Dumpty—he's their old friend of the story-book. My poor Humpty Dumpty! It was all my fault for letting him fall when he was little.' . . ." The girl's voice faltered, and she put her handkerchief to her eyes.

    "So she mentioned to you that the children called Drukker Humpty Dumpty." Vance reached slowly in his pocket for his cigarette-case.

    She nodded, and a moment later lifted her head as if forcing herself to face something she dreaded.

    "Yes! And that's what was so strange; for after a little while she shuddered and drew back from the wall. I asked her what was the matter, and she said in a terrified voice: 'Suppose, Belle—suppose that Adolph should ever fall off of this wall—the way the real Humpty Dumpty did!' I was almost afraid myself; but I forced a smile, and told her she was foolish. It didn't do any good, though. She shook her head and gave me a look that sent a chill through me. 'I'm not foolish,' she said. 'Wasn't Cock Robin killed with a bow and arrow, and wasn't Johnny Sprig shot with a little gun—right here in New York?'" The girl turned a frightened gaze upon us. "And it did happen, didn't it—just as she foresaw?"

    "Yes, it happened," Vance nodded. "But we mustn't be mystical about it. Mrs. Drukker's imagination was abnormal. All manner of wild conjectures went through her tortured mind; and with these two other Mother-Goose deaths so vivid in her memory, it's not remarkable that she should have turned the children's sobriquet for her son into a tragic speculation of that kind. That he should actually have been killed in the manner she feared is nothing more than a coincidence. . . ."

    He paused and drew deeply on his cigarette.

    "I say, Miss Dillard," he asked negligently; "did you, by any chance, repeat your conversation with Mrs. Drukker to any one yesterday?"

    She regarded him with some surprise before answering.

    "I mentioned it at dinner last night. It worried me all the afternoon, and—somehow—I didn't want to keep it to myself."

    "Were any comments made about it?"

    "Uncle told me I shouldn't spend so much time with Lady Mae—that she was unhealthily morbid. He said the situation was very tragic, but that there was no need for me to share Lady Mae's suffering. Mr. Pardee agreed with uncle. He was very sympathetic, and asked if something could not be done to help Lady Mae's mental condition."

    "And Mr. Arnesson?"

    "Oh, Sigurd never takes anything seriously,—I hate his attitude sometimes. He laughed as though it was a joke; and all he said was: 'It would be a shame if Adolph took his tumble before he got his new quantum problem worked out.'"

    "Is Mr. Arnesson at home now, by the by?" asked Vance. "We want to ask him about the necess'ry arrangements in regard to the Drukkers."

    "He went to the university early this morning; but he'll be back before lunch. He'll attend to everything, I am sure. We were about the only friends Lady Mae and Adolph had. I'll take charge in the meantime and see that Grete gets the house in order."

    A few minutes later we left her and went to interview Professor Dillard.