“I darted down the walk and into Montegut Street and paused at the corner of Burgundy, thinking.”

Pendergast hesitated, and a new expression — dismay? Self-reproach? — moved across his face.

“As I said, I intended to place the tooth under his pillow while he slept, then tell my uncle to replace it with a coin. But I was still angry at my brother. And I was afraid Diogenes would wake up when I slid the tooth under the pillow, or might otherwise learn of the deception. In that case he would probably take the tooth from under the pillow and bring it back to the old man’s porch, frustrating my plan to teach him a lesson. This brought on another surge of annoyance. How could my brother believe such drivel? And why was I wasting my time on it, spending hours crouched in the darkness? I’d show him how stupid he’d been. And so — in a childish fit of petulance — I flung the tooth down a storm drain at the corner of Montegut and Burgundy.

“As I did so, I caught, out of the corner of my eye, a flicker of light from the broken oriel window high up in the mansion, as if the broken glass had briefly refracted the light of a lantern. I also saw — or thought I saw — a movement there, a shadow suddenly in motion, flitting away. But as I stared harder, I could see nothing further; no shadow, no movement, just the same dull glow. It had been my fancy, nothing more. Nobody had seen me either take the tooth or throw it away. I was letting my imagination run wild.

“I went home as quickly as I could. When I got there, Diogenes was awake and waiting for me. He looked at me, his young face creased with wariness and distrust. In triumph, I told him what I’d done and why. I chastised him again for his ridiculous and childish superstitions. I told him I hoped this would be a lesson to him. I was quite awful, and I’m ashamed even today to think of how I behaved. The tragedy of how Diogenes turned out must partly be laid on my shoulders.”

Pendergast fell silent for a long moment, and then resumed. “He flew into a fit such as I’d never seen before. ‘Old Dufour’s going to come!’ he cried in terror, the tears springing to his eyes. ‘You stole his tooth, and now he’s going to come—for me!’

“I was taken aback but still maintained the superior, older-and-wiser-brother attitude. I said Dufour would certainly not come, that he had no idea he was considered the tooth fairy, and that he had seen neither Diogenes nor me and was unaware a tooth had even been left. But Diogenes didn’t believe a word of it; he insisted that Dufour’s entire existence was for teeth, that he waited for them every night, that he treasured them, and that he had surely seen everything both he and I had done that night.

“The very violence and rawness of emotion — unusual for him — shocked me. This was when I began to realize I had done something wrong — very wrong. I felt guilty and ashamed. I saw that my own behavior had been cruel. Diogenes alternated between juvenile paroxysms of rage and spells of crying — the only time that I can remember ever seeing him cry. And so I apologized. I tried to point out, in my youthful way, how unreasonable his fears were. I promised to protect him. Nothing helped. In the end, I grew frustrated myself with his hysterics and left for my own bedroom.

“Old Dufour didn’t come for him that night. In the morning, at the breakfast table, Diogenes was silent and morose. I pointed out to him again that his fears were totally unfounded. But even as I was explaining that, I felt uneasy recalling the emptiness of the cuspidor, the absence of other teeth. There were dozens, even hundreds of children in the French Quarter; surely the teeth would have piled up. So where were they? Why weren’t there at least a few others in the cuspidor? But I dismissed such thoughts as best I could.

“At lunch Diogenes remained the same — agitated, resentful, and upset. Sometime in the middle of the afternoon, he vanished. He frequently went away like that — without telling anyone where he was going or, upon returning, where he had been — so, even under the circumstances, I wasn’t particularly concerned. I figured he was off hiding in a closet with one of his forbidden books or indulging in some childish experiment in the vast basement of our home.

“He had not returned by dinner. Uncle Everett was concerned until I assured him that Diogenes often disappeared like this and that he should not worry. After dinner, over his brandy and cigar, Uncle Everett complained about ‘improper nocturnal perambulations for one so young,’ but I once again reassured him that Diogenes would soon reappear. Satisfied, my uncle went up to bed.

“Diogenes was still missing in the morning, and now the household grew alarmed. Uncle Everett gave me a serious dressing-down for leading him to think it hadn’t been a problem. I was in agony, wondering if I should tell him what had happened the day before. But I was still fairly sure Diogenes, angry at what I’d done, had gone off sulking and was safe and sound in some hiding place. After a thorough search of the house turned up nothing, Uncle called the police. All attempts at locating my brother proved fruitless. Various unsavory locales in the French Quarter were searched, as well as the tracks along the waterfront, the Canal Street piers, and Woldenberg Park. Finally, around four in the afternoon of August twenty-seventh, when my uncle was agitating to have the waterfront dragged, I broke down and told him what had transpired two days before. At this point I had begun to be afraid, and yet still not quite believing, that maybe Diogenes had been right… and Old Dufour had come for him.

“My uncle was highly skeptical — to say the least. He certainly could not take such a notion to the police, he said — it was too patently absurd. But he was worried sick and especially frightened of our father, who was an irascible and even violent man and who, on his return, would blame him for losing his son and might thrash him. In the end he sighed, wiped his face, and said, ‘I suppose one must try every avenue. I will go myself to see Monsieur Dufour.’

“He roused himself and I watched from the front parlor window as he walked down the lane, in the direction of Montegut Street. I expected him to return within the hour. Instead, he was gone almost four hours. But then at last — it was nearly midnight, and I was sitting on the main staircase, unable to sleep — I heard a key fumbling in the lock of the front door. There was my uncle Everett, with Diogenes at his side. My brother was ashen, stone-faced. He immediately and wordlessly went up to his room, closed and locked his door, and did not come out for several days.”

Pendergast paused. The Riverside Drive mansion had gone very silent. The fire had died down, and the coals were crackling very quietly on the grate. The windows were closed tight and covered with heavy drapes; no sound of the traffic outside filtered in to the hush of the library. After another moment, Pendergast continued.

“But my uncle looked terrible. Hideous in fact. He was strangely disheveled, very unlike him, and his eyes were deeply bloodshot. His face looked all wrong, somehow: his jaws sunken, his cheeks hollow, his lips trembling as if palsied, but the lower portion grossly swollen, as if he were carrying water in his mouth. And the color of his skin — it was crimson, almost purple, and there was a cut on his cheek. He stared at me with a dreadful expression — his mouth set, a hard glitter to his eyes — I had never seen in him before. I fancied I saw flecks of blood on his collar.

“He went into the back part of the house and called for the housekeeper. When I heard his voice, I was shocked. It was changed, different — slurred and thick, as if he were drunk. I could only vaguely make out the conversation, but it seemed my uncle was requesting confirmation that my father would be returning the following day. He would be going out again immediately, he continued, and was entrusting myself and Diogenes to her care.