“Dr. Blumenthal,” Muriel said, stepping into the room, “I don’t have anybody to help you at the moment, but I can myself.”

“Wonderful,” Marissa said. “Let’s go to it.”

• • •

The sliding glass door opened automatically as Marissa strode into the lobby level of the Massachusetts Eye and Ear Infirmary. Despite the cool late-afternoon temperature she had on only her thin doctor’s white jacket. After a quick inquiry at the information booth, she veered right into the emergency area. She asked for Dr. Wilson at the emergency desk.

“She’s in the back,” the secretary said. She pointed through a pair of swinging doors that were propped open.

Marissa continued her search. Beyond the propped-open swinging doors were several ophthalmologic examining rooms, each with its barberlike chair and attached slit lamp. A lone patient sat in the first room Marissa went by. In the second, the room light was out and two figures were bent over a reclining patient. Allowing her eyes to adjust, Marissa recognized one of them as Wendy.

“Now press down gently and look where you are pressing,” Wendy said, guiding a junior resident through a specialized exam. “You should see the tear at the periphery of the retina.”

“I see it!” the resident cried.

“Good,” Wendy said. She caught sight of Marissa and waved. Turning back to the resident, she said, “Write it up and call the senior resident.”

Wendy came out of the darkened room, blinking in the raw fluorescent light of the main part of the emergency room. “This is a surprise,” she said. “What’s up?”

“I got a very interesting call from the CDC,” Marissa said. Then she lowered her voice. “Where can we talk?”

Wendy thought for a minute, then took Marissa around the back of the emergency area into an empty laser room. She shut the heavy door behind them. “You look positively mischievous. What’s going on?”

“You’re not going to believe this,” Marissa began. She then told Wendy the gist of Dubchek’s call indicating that they were dealing with a problem that had national scope.

“My word! We’re on the brink of some major discovery,” Wendy said, catching Marissa’s enthusiasm.

“I don’t think there is any doubt,” Marissa said. “And there is only one minor barrier to the whole denouement.”

“Wingate,” Wendy said.

“Exactly!” Marissa said. “We have to see if there are more cases. I’m sure there are. There have to be. Once we have them all, we can begin to look for areas of commonality in all the subjects in terms of life-style, work, health history, all that. I’m sure if we do that with enough cases we’ll come up with a theory as to the source of the TB and how it is being transmitted. Usually TB is airborne. But if no one has any lung lesions, maybe it’s traveling by some other means.”

“So what do you propose?” Wendy asked.