He was alone in his office, and the automatic lock was adjusted to Dr. Henree's fingerprints only. He could feel some of his depression lifting. David Starr was on his way, suddenly and magically grown up, ready to receive his first assignment as a member of the Council. He felt almost as though his son were about to visit him. In a way, that was how it was. David Starr was his son: his and Augustus Henree's.

There had been three of them at first, himself and Gus Henree and Lawrence Starr. How he remembered Lawrence Starr! They had all three gone through school together, qualified for the Council together, done their first investigations together; and then Lawrence Starr had been promoted. It was to be expected; he was by far the most brilliant of the three.

So he had received a semi-permanent station on Venus, and that was the first time the three had not tackled a proposition together. He had gone with his wife and child. The wife was Barbara. Lovely Barbara Starr! Neither Henree nor himself had ever married, and for neither were there any girls to compete with Barbara in memory. When David was born, it was Uncle Gus and Uncle Hector, until he sometimes got confused and called his father Uncle Lawrence.

And then on the trip to Venus there was the pirate attack. It had been a total massacre. Pirate ships took virtually no prisoners in space, and more than a hundred human beings were dead before two hours had passed. Among them were Lawrence and Barbara.

Conway could remember the day, the exact minute, when the news had reached Science Tower. Patrol ships had shot out into space, tracing the pirates; they attacked the asteroid lairs in a fury that was completely unprecedented. Whether they caught the particular villains who had gutted the Venus-bound ship none could ever say, but the pirate power had been broken from that year on.

And the patrol ships found something else: a tiny lifeboat winding a precarious orbit between Venus and Earth, radiating its coldly automatic radio calls for help. Only a child was inside. A frightened, lonely four-year-old, who did not speak for hours except to say stoutly, "Mother said I wasn't to cry."

It was David Starr. His story, seen through childish eyes, was garbled, but interpretation was only too easy. Conway could still see what those last minutes within the gutted ship must have been like: Lawrence Starr, dying in the control room, with the outlaws forcing their way in; Barbara, a blast gun in her hand, desperately thrusting David into the lifeboat, trying to set the controls as best she could, rocketing it into space. And then?

She had a gun in her hand. As long as she could, she must have used it against the enemy, and when that could be no longer, against herself.

Conway ached to think of it. Ached, and once again wished they had allowed him to accompany the patrol ships so that with his own hands he might have helped to turn the asteroid caves into flaming oceans of atomic destruction. But members of the Council of Science, they said, were too valuable to risk in police actions, so he stayed home and read the news bulletins as they rolled out on the ticker tape of his telenews projector.

Between them he and Augustus Henree had adopted David Starr, bent their lives to erase those last horrible memories of space. They were both mother and father to him; they personally supervised his tutoring; they trained him with one thought in mind: to make him what Lawrence Starr had once been.

He had exceeded their expectations. In height he was Lawrence, reaching six feet, rangy and hard, with the cool nerves and quick muscles of an athlete and the sharp, clear brain of a first-class scientist. And beyond that there was something about his brown hair with the suggestion of a wave in it, in his level, wide-set brown eyes, in the trace of a cleft in his chin which vanished when he smiled, that was reminiscent of Barbara.

He had raced through his Academy days leaving a trail of sparks and the dead ash of previous records both on the playing fields and in the classrooms.

Conway had been perturbed. "It's not natural, Gus. He's outdoing his father."

And Henree, who didn't believe in unnecessary speech, had puffed at his pipe and smiled proudly.

"I hate to say this," Conway had continued, "because you'll laugh at me, but there's something not quite normal in it. Remember that the child was stranded in space for two days with just a thin lifeboat hull between himself and solar radiation. He was only seventy million miles from the sun during a period of sunspot maximum."

"All you're saying," said Henree, "is that David should have been burnt to death."

"Well, I don't know," mumbled Conway. "The effect of radiation on living tissue, on human living tissue, has its mysteries."

"Well, naturally. It's not a field in which experimentation is very feasible."

David had finished college with the highest average on record. He had managed to do original work in biophysics on the graduate level. He was the youngest man ever to be accorded full membership in the Council of Science.

To Conway there had been a loss in all this. Four years earlier he had been elected Chief Counselor. It was an honor he would have given his life for, yet he knew that had Lawrence Starr lived, the election would have gone in a worthier direction.

And he had lost all but occasional contact with young David Starr, for to be Chief Counselor meant that one had no life other than the beetling problems of all the Galaxy. Even at graduation exercises he had seen David only from a distance. In the last four years he might have spoken to him four times.

So Ms heart beat high when he heard the door open. He turned, walking rapidly to meet them as they walked in.

"Gus old man." He held out his hand, wrung the other's. "And David boy!"

An hour passed. It was true night before they could stop speaking of themselves and turn to the universe.

It was David who broke out. He said, "I saw my first poisoning today, Uncle Hector. I knew enough to prevent panic. I wish I knew enough to prevent poisoning."

Conway said soberly, "No one knows that much. I suppose, Gus, it was a Martian product again."

"No way of telling, Hector. But a marplum was involved."

"Suppose," said David Starr, "you let me know anything I'm allowed to know about this."

"It's remarkably simple," said Conway. "Horribly simple. In the last four months something like two hundred people have died immediately after eating some Mars-grown product. It's no known poison, the symptoms are those of no known disease. There is a rapid and complete paralysis of the nerves controlling the diaphragm and the muscles of the chest. It amounts to a paralysis of the lungs, which is fatal in five minutes.

"It goes deeper than that too. In the few cases where we've caught the victims in time, we've tried artificial respiration, as you did, and even iron lungs. They still died in five minutes. The heart is affected as well. Autopsies show us nothing except nerve degeneration that must have been unbelievably rapid."

"What about the food that poisoned them?" asked David.

"Dead end," said Conway. "There is always time for the poisoned item or portion to be completely consumed. Other specimens of the same sort at the table or in the kitchen are harmless. We've fed them to animals and even to human volunteers. The stomach contents of the dead men have yielded uncertain results."

"Then how do you know it's food poisoning at all?"

"Because the coincidence of death after eating a Martian product time after time, without known exception, is more than coincidence."

David said thoughtfully, "And it isn't contagious, obviously."

"No. Thank the stars for that. Even so, it's bad enough. So far we've kept this as quiet as we can, with full co-operation from the Planetary Police. Two hundred deaths in four months over the population of all Earth is still a manageable phenomenon, but the rate may increase. And if the people of Earth become aware that any mouthful of Martian food might be their last, the consequences could be horrible. Even though we were to point out that the death rate is only fifty per month out of a population of five billions, each person would think himself certain to be one of those fifty."