Jack ran the fingers of both hands through his hair while laughing at Chet’s absurd suggestions. “Of course you’re right! But what a strange coincidence, especially when you add the anthrax to the picture, and the case of human anthrax I had yesterday here in Manhattan. What a couple of days!”

“Well, I’m going to leave you to ponder these mysteries,” Chet said. “While I go ponder another more enjoyable one in aerobics class.”

“Excuse me, Dr. Stapleton!”

Jack and Chet turned to see Peter Letterman standing in the doorway in his long white coat with its inevitable pattern of colorful stains. He was holding a computer printout.

“Peter!” Jack said eagerly. He searched the man’s face for a hint of his news, but Peter’s delicate features were unrevealing.

“I’ve run all the assays you suggested,” Peter said.

“And?” Jack questioned expectantly. It was like waiting for the envelope to be opened at the Academy Awards.

Peter handed Jack the printout. Jack scanned it. He had no idea what he was looking at.

“Everything came out negative,” Peter said guiltily. “I haven’t found anything.”

“Nothing?” Jack questioned. He looked up. He was dismayed.

Peter shook his head. “I’m sorry. I know you were counting on a positive, so I ran some of the assays several times. Everything came back negative.”

“Oh, crap!” Jack said. He threw up his hands. “So much for my intuition. Maybe even my job.”

“You checked for carbon monoxide?” Chet asked.

“Absolutely,” Peter said.

“And cyanide?” Chet asked.

“Everything that Dr. Stapleton requested plus a few drugs he didn’t mention.”

“Thank you very much,” Jack said. “At the moment I might not sound as appreciative as I should, but I am thankful for you staying late and doing this.”

“If you can think of anything else you want me to test for, give me a call.”

“Right,” Jack said.

Peter left.

“Oh, well,” Jack said. He threw his pen onto his desk. Then he started gathering together all the disparate papers from the various cases and jamming them into their folders.

Chet watched for a few minutes. “If I can think of anything else to test for, I’ll give you a call.”

Jack gave him a weak smile and continued straightening up.

“Are you heading home?” Chet asked.

“Yup,” Jack said. “I think I need a little physical activity myself.”

After saying goodbye, Chet left. As Jack moved his microscope over onto his own desk, he thought about all the strange events over the previous twenty-four hours. It was all a mystery, yet he had to smile. Such conundrums were, after all, what he liked about the job.

After locking his office door, Jack glanced down the hall toward Laurie’s. It was closed. Obviously, Laurie had left without saying goodbye. Jack shrugged. He really didn’t know what to do about her.