Chapter 2

His voice trailed off. Very likely, when the ship returned, it would find an empty base. The first-string team simply wasn't set up for exhaustive work; its job was to survey the field in general and mark out the problems for the complete team to solve.

Establishing the base had been of primary importance, and that was the sort of equipment that had been carried on the ship. That--and food. The scientists had only the barest essentials to work with; they had no electron microscopes or any of the other complex instruments necessary for exhaustive biochemical work.

Now that they were engaged in a fight for survival, they felt like a gang of midgets attacking a herd of water-buffalo with penknives. Even if they won the battle, the mortality rate would be high, and their chances of winning were pretty small.

The Space Service officers and the scientists discussed the problem for over an hour, but they came to no promising conclusion.

At last, Colonel Fennister said: "Very well, Dr. Pilar; we'll have to leave the food supply problem in your hands. Meanwhile, I'll try to keep order here in the camp."

* * * * *

SM/2 Broderick MacNeil may not have had a top-level grade of intelligence, but by the end of the second week, his conscience was nagging him, and he was beginning to wonder who was goofing and why. After much thinking--if we may so refer to MacNeil's painful cerebral processes--he decided to ask a few cautious questions.

Going without food tends to make for mental fogginess, snarling tempers, and general physical lassitude in any group of men. And, while quarter rations were not quite starvation meals, they closely approached it. It was fortunate, therefore, that MacNeil decided to approach Dr. Pilar.

Dr. Petrelli's temper, waspish by nature, had become positively virulent in the two weeks that had passed since the destruction of the major food cache. Dr. Smathers was losing weight from his excess, but his heretofore pampered stomach was voicelessly screaming along his nerve passages, and his fingers had become shaky, which is unnerving in a surgeon, so his temper was no better than Petrelli's.

Pilar, of course, was no better fed, but he was calmer than either of the others by disposition, and his lean frame didn't use as much energy. So, when the big hulking spaceman appeared at the door of his office with his cap in his hands, he was inclined to be less brusque than he might have been.

"Yes? What is it?" he asked. He had been correlating notes in his journal with the thought in the back of his mind that he would never finish it, but he felt that a small respite might be relaxing.

MacNeil came in and looked nervously around at the plain walls of the pre-fab plastic dome-hut as though seeking consolation from them. Then he straightened himself in the approved military manner and looked at the doctor.

"You Dr. Piller? Sir?"

"Pi_lar_," said the scientist in correction. "If you're looking for the medic, you'll want Dr. Smathers, over in G Section."

"Oh, yessir," said MacNeil quickly, "I know that. But I ain't sick." He didn't feel _that_ sick, anyway. "I'm Spaceman Second MacNeil, sir, from B Company. Could I ask you something, sir?"

Pilar sighed a little, then smiled. "Go ahead, spaceman."

MacNeil wondered if maybe he'd ought to ask the doctor about his sacroiliac pains, then decided against it. This wasn't the time for it. "Well, about the food. Uh ... Doc, can men eat monkey food all right?"

Pilar smiled. "Yes. What food there is left for the monkeys has already been sent to the men's mess hall." He didn't add that the lab animals would be the next to go. Quick-frozen, they might help eke out the dwindling food supply, but it would be better not to let the men know what they were eating for a while. When they got hungry enough, they wouldn't care.

But MacNeil was plainly puzzled by Pilar's answer. He decided to approach the stuff as obliquely as he knew how.

"Doc, sir, if I ... I uh ... well--" He took the bit in his teeth and plunged ahead. "If I done something against the regulations, would you have to report me to Captain Bellwether?"

Dr. Pilar leaned back in his chair and looked at the big man with interest. "Well," he said carefully, "that would all depend on what it was. If it was something really ... ah ... dangerous to the welfare of the expedition, I'd have to say something about it, I suppose, but I'm not a military officer, and minor infractions don't concern me."

MacNeil absorbed that "Well, sir, this ain't much, really--I ate something I shouldn't of."

Pilar drew down his brows. "Stealing food, I'm afraid, would be a major offense, under the circumstances."

MacNeil looked both startled and insulted. "Oh, nossir! I never swiped no food! In fact, I've been givin' my chow to my buddies."

Pilar's brows lifted. He suddenly realized that the man before him looked in exceptionally good health for one who had been on a marginal diet for two weeks. "Then what _have_ you been living on?"

"The monkey food, sir."

"_Monkey food?_"

"Yessir. Them greenish things with the purple spots. You know--them fruits you feed the monkeys on."

Pilar looked at MacNeil goggle-eyed for a full thirty seconds before he burst into action.

* * * * *

"No, of course I won't punish him," said Colonel Fennister. "Something will have to go on the record, naturally, but I'll just restrict him to barracks for thirty days and then recommend him for light duty. But are you _sure_?"

"I'm sure," said Pilar, half in wonder.

Fennister glanced over at Dr. Smathers, now noticeably thinner in the face. The medic was looking over MacNeil's record. "But if that fruit kills monkeys and rats and guinea pigs, how can a _man_ eat it?"

"Animals differ," said Smathers, without taking his eyes off the record sheets. He didn't amplify the statement.

The colonel looked back at Pilar.

"That's the trouble with test animals," Dr. Pilar said, ruffling his gray beard with a fingertip. "You take a rat, for instance. A rat can live on a diet that would kill a monkey. If there's no vitamin A in the diet, the monkey dies, but the rat makes his own vitamin A; he doesn't need to import it, you might say, since he can synthesize it in his own body. But a monkey can't.

"That's just one example. There are hundreds that we know of and God alone knows how many that we haven't found yet."

Fennister settled his own body more comfortably in the chair and scratched his head thoughtfully. "Then, even after a piece of alien vegetation has passed all the animal tests, you still couldn't be sure it wouldn't kill a human?"

"That's right. That's why we ask for volunteers. But we haven't lost a man so far. Sometimes a volunteer will get pretty sick, but if a food passes all the other tests, you can usually depend on its not killing a human being."

"I gather that this is a pretty unusual case, then?"

Pilar frowned. "As far as I know, yes. But if something kills all the test animals, we don't ask for humans to try it out. We assume the worst and forget it." He looked musingly at the wall. "I wonder how many edible plants we've by-passed that way?" he asked softly, half to himself.

"What are you going to do next?" the colonel asked. "My men are getting hungry."

Smathers looked up from the report in alarm, and Pilar had a similar expression on his face.

"For Pete's sake," said Smathers, "don't tell anyone--not _anyone_--about this, just yet. We don't want all your men rushing out in the forest to gobble down those things until we are more sure of them. Give us a few more days at least."

The colonel patted the air with a hand. "Don't worry. I'll wait until you give me the go-ahead. But I'll want to know your plans."

Pilar pursed his lips for a moment before he spoke. "We'll check up on MacNeil for another forty-eight hours. We'd like to have him transferred over here, so that we can keep him in isolation. We'll feed him more of the ... uh ... what'd he call 'em, Smathers?"

"Banana-pears."

"We'll feed him more banana-pears, and keep checking. If he is still in good shape, we'll ask for volunteers."

"Good enough," said the colonel. "I'll keep in touch."

* * * * *

On the morning of the third day in isolation, MacNeil rose early, as usual, gulped down his normal assortment of vitamins, added a couple of aspirin tablets, and took a dose of Epsom salts for good measure. Then he yawned and leaned back to wait for breakfast. He was certainly getting enough fresh fruit, that was certain. He'd begun to worry about whether he was getting a balanced diet--he'd heard that a balanced diet was very important--but he figured that the doctors knew what they were doing. Leave it up to them.

He'd been probed and needled and tested plenty in the last couple of days, but he didn't mind it. It gave him a feeling of confidence to know that the doctors were taking care of him. Maybe he ought to tell them about his various troubles; they all seemed like nice guys. On the other hand, it wouldn't do to get booted out of the Service. He'd think it over for a while.

He settled back to doze a little while he waited for his breakfast to be served. Sure was nice to be taken care of.

* * * * *

Later on that same day, Dr. Pilar put out a call for volunteers. He still said nothing about MacNeil; he simply asked the colonel to say that it had been eaten successfully by a test animal.

The volunteers ate their banana-pears for lunch, approaching them warily at first, but soon polishing them off with gusto, proclaiming them to have a fine taste.

The next morning, they felt weak and listless.

Thirty-six hours later, they were dead.

"Oxygen starvation," said Smathers angrily, when he had completed the autopsies.

Broderick MacNeil munched pleasantly on a banana-pear that evening, happily unaware that three of his buddies had died of eating that self-same fruit.

* * * * *

The chemist, Dr. Petrelli, looked at the fruit in his hand, snarled suddenly, and smashed it to the floor. Its skin burst, splattering pulp all over the gray plastic.

"It looks," he said in a high, savage voice, "as if that hulking idiot will be the only one left alive when the ship returns!" He turned to look at Smathers, who was peering through a binocular microscope. "Smathers, what makes him different?"

"How do I know?" growled Dr. Smathers, still peering. "There's something different about him, that's all."

Petrelli forcibly restrained his temper. "Very funny," he snapped.

"Not funny at all," Smathers snapped back. "No two human beings are identical--you know that." He lifted his gaze from the eyepiece of the instrument and settled in on the chemist. "He's got AB blood type, for one thing, which none of the volunteers had. Is that what makes him immune to whatever poison is in those things? I don't know.

"Were the other three allergic to some protein substance in the fruit, while MacNeil isn't? I don't know.

"Do his digestive processes destroy the poison? I don't know.

"It's got something to do with his blood, I think, but I can't even be sure of that. The leucocytes are a little high, the red cell count is a little low, the hemoglobin shows a little high on the colorimeter, but none of 'em seems enough to do any harm.

"It might be an enzyme that destroys the ability of the cells to utilize oxygen. It might be _anything_!"

His eyes narrowed then, as he looked at the chemist. "After all, why haven't you isolated the stuff from the fruit?"

"There's no clue as to what to look for," said Petrelli, somewhat less bitingly. "The poison might be present in microscopic amounts. Do you know how much botulin toxin it takes to kill a man? A fraction of a milligram!"

Smathers looked as though he were about to quote the minimum dosage, so Petrelli charged on: "If you think anyone could isolate an unknown organic compound out of a--"

"Gentlemen! _Please!_" said Dr. Pilar sharply. "I realize that this is a strain, but bickering won't help. What about your latest tests on MacNeil, Dr. Smathers?"

"As far as I can tell, he's in fine health. And I can't understand why," said the physician in a restrained voice.

Pilar tapped one of the report sheets. "You mean the vitamins?"

"I mean the vitamins," said Smathers. "According to Dr. Petrelli, the fruits contain neither A nor B_1. After living solely on them for four weeks now, he should be beginning to show some deficiencies--but he's not.

"No signs?" queried Dr. Pilar. "No symptoms?"

"No signs--at least no abnormal ones. He's not getting enough protein, but, then, none of us is." He made a bitter face. "But he has plenty of symptoms."

Dr. Petrelli raised a thin eyebrow. "What's the difference between a sign and a symptom?"

"A sign," said Smathers testily, "is something that can be objectively checked by another person than the patient. Lesions, swellings, inflammations, erratic heartbeat, and so on. A symptom is a subjective feeling of the patient, like aches, pains, nausea, dizziness, or spots before the eyes.

"And MacNeil is beginning to get all kinds of symptoms. Trouble is, he's got a record of hypochondria, and I can't tell which of the symptoms are psychosomatic and which, if any, might be caused by the fruit."

"The trouble is," said Petrelli, "that we have an unidentifiable disease caused by an unidentifiable agent which is checked by an unidentifiable something in MacNeil. And we have neither the time nor the equipment to find out. This is a job that a fully equipped research lab might take a couple of years to solve."

"We can keep trying," said Pilar, "and hope we stumble across it by accident."

Petrelli nodded and picked up the beaker he'd been heating over an electric plate. He added a chelating agent which, if there were any nickel present, would sequester the nickel ions and bring them out of solution as a brick-red precipitate.

Smathers scowled and bent over his microscope to count more leucocytes.

Pilar pushed his notes aside and went over to check his agar plates in the constant-temperature box.

The technicians who had been listening to the conversation with ears wide open went back to their various duties.

And all of them tried in vain to fight down the hunger pangs that were corroding at their insides.

* * * * *

Broderick MacNeil lay in his bed and felt pleasantly ill. He treasured each one of his various symptoms; each pain and ache was just right. He hadn't been so comfortable in years. It really felt fine to have all those doctors fussing over him. They got snappy and irritable once in a while, but then, all them brainy people had a tendency to do that. He wondered how the rest of the boys were doing on their diet of banana-pears. Too bad they weren't getting any special treatment.

MacNeil had decided just that morning that he'd leave the whole state of his health in the hands of the doctors. No need for a fellow to dose himself when there were three medics on the job, was there? If he needed anything, they'd give it to him, so he'd decided to take no medicine.

A delightful, dulling lassitude was creeping over him.

* * * * *

"MacNeil! _MacNeil!_ Wake up, MacNeil!"

The spaceman vaguely heard the voice, and tried to respond, but a sudden dizziness overtook him. His stomach felt as though it were going to come loose from his interior.

"I'm sick," he said weakly. Then, with a terrible realization, "I'm really _awful_ sick!"

He saw Dr. Smathers' face swimming above him and tried to lift himself from the bed. "Shoulda taken pills," he said through the haze that was beginning to fold over him again. "Locker box." And then he was unconscious again.

Dr. Smathers looked at him bleakly. The same thing was killing MacNeil as had killed the others. It had taken longer--much longer. But it had come.

And then the meaning of the spaceman's mumbled words came to him. Pills? Locker box?

He grabbed the unconscious man's right hand and shoved his right thumb up against the sensor plate in the front of the metal box next to the bed. He could have gotten the master key from Colonel Fennister, but he hadn't the time.

The box door dilated open, and Dr. Smathers looked inside.

When he came across the bottles, he swore under his breath, then flung the spaceman's arm down and ran from the room.

* * * * *

"That's where he was getting his vitamins, then," said Dr. Pilar as he looked over the assortment of bottles that he and Smathers had taken from the locker box. "Look at 'em. He's got almost as many pills as you have." He looked up at the physician. "Do you suppose it was just vitamins that kept him going?"

"I don't know," said Smathers. "I've given him massive doses of every one of the vitamins--from my own supplies, naturally. He may rally round, if that's what it was. But why would he suddenly be affected by the stuff _now_?"

"Maybe he quit taking them?" Pilar made it half a question.

"It's possible," agreed Smathers. "A hypochondriac will sometimes leave off dosing himself if there's a doctor around to do it for him. As long as the subconscious need is filled, he's happy." But he was shaking his head.

"What's the matter?" Pilar asked.

Smathers pointed at the bottles. "Some of those are mislabeled. They all say vitamins of one kind or another on the label, but the tablets inside aren't all vitamins. MacNeil's been giving himself all kinds of things."

Pilar's eyes widened a trifle. "Do you suppose--"

"That one of them is an antidote?" Smathers snorted. "Hell, anything's possible at this stage of the game. The best thing we can do, I think, is give him a dose of everything there, and see what happens."

* * * * *

"Yeah, Doc, yeah," said MacNeil smiling weakly, "I feel a little better. Not real good, you understand, but better."

Under iron control, Dr. Smathers put on his best bedside manner, while Pilar and Petrelli hovered in the background.

"Now, look, son," said Smathers in a kindly voice, "we found the medicines in your locker box."

MacNeil's face fell, making him look worse. He'd dropped down close to death before the conglomerate mixture which had been pumped into his stomach had taken effect, and Smathers had no desire to put too much pressure on the man.

"Now, don't worry about it, son," he said hurriedly; "We'll see to it that you aren't punished for it. It's all right. We just want to ask you a few questions."

"Sure, Doc; anything," said MacNeil. But he still looked apprehensive.

"Have you been dosing yourself pretty regularly with these things?"

"Well ... uh ... well, yeah. Sometimes." He smiled feebly. "Sometimes I didn't feel so good, and I didn't want to bother the medics. You know how it is."

"Very considerate, I'm sure," said Smathers with just the barest trace of sarcasm, which, fortunately, fell unheeded on MacNeil's ears. "But which ones did you take every day?"

"Just the vitamins." He paused. "And ... uh ... maybe an aspirin. The only things I took real regular were the vitamins, though. That's all right ain't it? Ain't vitamins food?"

"Sure, son, sure. What did you take yesterday morning, before you got so sick?"

"Just the vitamins," MacNeil said stoutly. "I figured that since you docs was takin' care of me, I didn't need no medicine."

Dr. Smathers glanced up hopelessly at the other two men. "That eliminates the vitamins," he said, _sotto voce_. He looked back at the patient. "No aspirin? No APC's? You didn't have a headache at all?"

MacNeil shook his head firmly. "I don't get headaches much." Again he essayed a feeble smile. "I ain't like you guys, I don't overwork my brains."

"I'm sure you don't," said Smathers. Then his eyes gleamed. "You have quite a bit of stomach trouble, eh? Your digestion bad?"

"Yeah. You know; I told you about it. I get heartburn and acid stomach pretty often. And constipation."

"What do you take for that?"

"Oh, different things. Sometimes a soda pill, sometimes milk of magnesia, different things."

Smathers looked disappointed, but before he could say anything, Dr. Petrelli's awed but excited voice came from behind him. "Do you take Epsom salts?"

"Yeah."

"I wonder--" said Petrelli softly.

And then he left for the lab at a dead run.

* * * * *

Colonel Fennister and Major Grodski sat at the table in the lab, munching on banana-pears, blissfully enjoying the sweet flavor and the feeling of fullness they were imparting to their stomachs.

"MacNeil can't stay in the service, of course," said Fennister. "That is, not in any space-going outfit. We'll find an Earthside job for him, though. Maybe even give him a medal. You sure these things won't hurt us?"

Dr. Pilar started to speak, but Petrelli cut him off.

"Positive," said the chemist. "After we worked it out, it was pretty simple. The 'poison' was a chelating agent, that's all. You saw the test run I did for you."

The colonel nodded. He'd watched the little chemist add an iron salt to some of the fruit juice and seen it turn red. Then he'd seen it turn pale yellow when a magnesium salt was added. "But what's a chelating agent?" he asked.

"There are certain organic compounds," Dr. Petrelli explained, "that are ... well, to put it simply, they're attracted by certain ions. Some are attracted by one ion, some by another. The chelating molecules cluster around the ion and take it out of circulation, so to speak; they neutralize it, in a way.

"Look, suppose you had a dangerous criminal on the loose, and didn't have any way to kill him. If you kept him surrounded by policemen all the time, he couldn't do anything. See?"

The Space Service Officers nodded their understanding.

"We call that 'sequestering' the ion," the chemist continued. "It's used quite frequently in medicine, as Dr. Smathers will tell you. For instance, beryllium ions in the body can be deadly; beryllium poisoning is nasty stuff. But if the patient is treated with the proper chelating agent, the ions are surrounded and don't do any more damage. They're still there, but now they're harmless, you see."

"Well, then," said the colonel, "just what did this stuff in the fruit do?"

"It sequestered the iron ions in the body. They couldn't do their job. The body had to quit making hemoglobin, because hemoglobin needs iron. So, since there was no hemoglobin in the bloodstream, the patient developed sudden pernicious anemia and died of oxygen starvation."

Colonel Fennister looked suddenly at Dr. Smathers. "I thought you said the blood looked normal."

"It did," said the physician. "The colorimeter showed extra hemoglobin, in fact. But the chelating agent in the fruit turns red when it's connected up with iron--in fact, it's even redder than blood hemoglobin. And the molecules containing the sequestered iron tend to stick to the outside of the red blood cells, which threw the whole test off."

"As I understand it, then," said Major Grodski, "the antidote for the ... uh ... chelating agent is magnesium?"

"That's right," said Dr. Petrelli, nodding. "The stuff prefers magnesium ions to ferrous ions. They fit better within the chelating ring. Any source of magnesium will do, so long as there's plenty of it. MacNeil was using milk of magnesia, which is the hydroxide, for 'gastric acidity'. It's changed to chloride in the stomach. And he was using Epsom salts--the sulfate, and magnesium citrate as laxatives. He was well protected with magnesium ions."

"We tried it ourselves first, naturally," said Dr. Pilar. "We haven't had any ill effects for two days, so I think we'll be able to make it until the ship comes."

Major Grodski sighed. "Well, if not, I'll at least die with a full stomach." He reached for another banana-pear, then looked over at Petrelli. "Pass the salt, please."