He watched, almost wistfully, as the huge man cut through the traffic and headed for the large glass doors. Then, with a sigh, he stepped on the starter button and snaked the little jet car into the stream of traffic moving toward the city.

Jeff Meyer stopped in the great, bustling lobby and stared about him almost in awe. He had never been inside the Hoffman Center before, though he had heard of it many times and in many places. Since it had taken over service of the huge metropolis of Boston-New Haven-New York-Philadelphia, the newspapers and TV had been full of stories of the lifesaving and healing that had gone on within its walls. The disease research, conducted by specialists in all phases of medicine who were for the first time gathered together under one agency, had startled the world again and again.

But there had been other stories, too—not from the papers and TV, not these stories. These tales had come by word of mouth: a short sentence or two, a nervous laugh, a sneering joke, a rumor, a whispered story from a wide-eyed alky hanging over a bar. Not the sort of stories one really believed, but the sort that made one wonder.

Several dozen white-garbed women moved across the floor of the huge lobby and talked quietly among themselves. Jeff sniffed uneasily. There was a curiously distasteful odor in the air, an odor of almost unhealthy cleanliness and spotless preservation. The lobby was a mill of activity: the elevators and interbuilding jitneys terminated here; people moved briskly, carrying with them the familiar air of hurry and vast pressure that infected the whole world outside.

Jeff watched, spotting the corridor leading to the main administrative offices. He saw the elevators constantly rising to and returning from the huge admission offices. He noted the corridor twisting off to the staff living quarters. He stood silent, his quick gray eyes cautiously probing and watching. He tried to print an indelible picture in his mind of the layout of the building and was almost floored by the hive-like bustle of the place. There was a complexity in the curved doorways and the brightly lighted corridors.

Somewhere here he could find Paul Conroe. Somewhere in this maze of buildings and passageways was the man he had hunted for. Logic told him that. They had spent the night searching every possible alternative. His muscles ached and his eyes were red from sleeplessness, but there was a hot, angry glow in his heart. He knew that this was the only place that Conroe could have gone. Yet the place where he must be hiding was a place Jeff had heard of only in rumor, a place whose mention carried with it a half-knowledge of staggering wealth and almost indescribable horror.

Someone tapped him on the shoulder. He turned, startled, to face a huge, burly man with a suspicious face and a gray uniform. "You got business here, mister, or are we just sight-seeing?"

Jeff forced a grin. "I don't know where to go," he said truthfully.

"Maybe you should go back out then. No visitors until this afternoon."

"No, I'm not a visitor. I'm looking for the Volunteer's Bank. The ads said to come to the administration offices—"

The guard's face softened a little. He pointed a finger toward a corridor marked RESEARCH ADMINISTRATION. "Right over there," he said. "Office is the first door to your right. The nurse will take care of you."

Meyer strolled toward the corridor, his mind fumbling with the rumors and bits of half-knowledge that were all that he had to work on: stories of drunks stumbling into the Emergency Rooms and never coming out; tales of quiet, swift raids on narcotics houses, of people who never reached the police stations.

But how could he make the right contact here? "Research Administration" covered a multitude of meanings. He had read the advertisements for Hoffman volunteers in all the buses, in the 'copters, on the roads. Newspapers and TV had carried them for years. Meyer glanced down at his unpolished shoes, rubbed a finger over his purposely unshaven chin. What would they expect a volunteer to look like? How could they detect a fraud, an interloper? He shivered as he faced the office door. It would be a gamble, a terrible chance. Because with all the other publicity, no mention had ever been made of the Mercy Men. He glanced back, found the guard still staring at him, and walked into the office.

Several people sat along the wall. A small, mousy-looking man with a bald head and close-set eyes had just sat down in the chair before the desk. He waited for the prim-looking woman wearing a ridiculous little white hat to put down her pen. She didn't even glance up as Jeff took a seat, and she kept writing for several minutes before turning her attention to the little bald man. Then she looked up and gave a frosty smile at him. "Yes, sir?"

"Dr. Bennet asked me to come back today," the little man said. "Follow-up on last week's work."

"Name please?" The woman took his name and punched the button on a panel before her; an instant later a card flipped down in a slot. She checked it, made an entry and nodded to the man. "Dr. Bennet will be ready for you at eleven. You'll find magazines in the lounge." She indicated another door, and the little man disappeared through it.

Another person, a middle-aged woman, moved to take the little man's place before the desk. Jeff felt restless and glanced at his watch. It was almost eleven. Must she move so slowly? Nothing seemed to hurry her. She worked from person to person, smiling, impersonal, just a trifle chilly. Finally she nodded to Jeff, and he moved to the chair.

"Name, please?"

"You don't have a card on me."

She looked up briefly. "A new volunteer? We're happy to have you, sir. Now if you'll give me your name, I can start the papers through."

Jeff cleared his throat, felt his pulse pounding in his forehead. "I'm not sure just what I want to volunteer for," he said cautiously.

The woman smiled. "We have a rather large selection to choose from. There are the regular 'mycin drug runs every week on Tuesdays and Thursdays. You take the drug by mouth in the morning and give blood samples at ten, two and four. Many of our new Volunteers start on that. It pays six dollars and your lunch while you're here. Or you could give blood, but the law restricts you to once every three months on that, and it only pays thirty-five dollars. Or—"

Jeff shook his head and leaned forward. He looked directly into her eyes. "I don't think you understand," he said softly. "I want money. Lots of it. Not five or ten dollars." He looked down at the desk. "I've heard you have other kinds of work."

The woman's eyes narrowed. "There are higher-paying categories of Volunteer work, of course. But you must understand that they are higher paying because they involve a greater risk to the health of the Volunteer. For instance, we've been running circulation studies with heart catheterizations. We pay a hundred dollars for these, but there is an appreciable risk involved. Or sternal marrow punctures for blood studies. Usually we start—"

"I said money," said Jeff implacably. "Not peanuts."

Her eyes widened and she stared at him for a long moment. It was a strange, penetrating stare that took him in from his face to his feet. Her smile faded and her fingers were suddenly nervous. "Have you any idea what you're talking about?"

"I have. I'm talking about the Mercy Men."

She stood up abruptly and disappeared into an inner office. Jeff waited, his whole body trembling. Beads of sweat broke out on his forehead, and he gave a visible start when the woman opened the door again.

"Come in here, please."

Then he was on the right track. He tried to conceal the excitement in his eyes as he took a seat in the small room. He waited, fidgeting. The woman packed up a small telephone on the desk and punched several buttons in rapid succession. The silence was almost intolerable as he waited, a silence that was alive and vibrant. Finally