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CUM GRANO SALIS.

BY DAVID GORDON

Illustrated by Emsh

     _Just because a man can do something others can't does not,
     unfortunately, mean he knows how to do it. One man could eat the
     native fruit and live ... but how?_


"And that," said Colonel Fennister glumly, "appears to be that."

The pile of glowing coals that had been Storage Shed Number One was
still sending up tongues of flame, but they were nothing compared with
what they'd been half an hour before.

"The smoke smells good, anyway," said Major Grodski, sniffing
appreciatively.

The colonel turned his head and glowered at his adjutant.

"There are times, Grodski, when your sense of humor is out of place."

"Yes, sir," said the major, still sniffing. "Funny thing for lightning
to do, though. Sort of a dirty trick, you might say."

"_You_ might," growled the colonel. He was a short, rather roundish man,
who was forever thankful that the Twentieth Century predictions of
skin-tight uniforms for the Space Service had never come true. He had
round, pleasant, blue eyes, a rather largish nose, and a rumbling basso
voice that was a little surprising the first time you heard it, but
which seemed to fit perfectly after you knew him better.

Right at the moment, he was filing data and recommendations in his
memory, where they would be instantly available for use when he needed
them. Not in a physical file, but in his own mind.

_All right, Colonel Fennister_, he thought to himself, _just what does
this mean--to me? And to the rest?_

The Space Service was not old. Unlike the Air Service, the Land Service,
or the Sea Service, it did not have centuries or tradition behind it.
But it had something else. It had something that none of the other
Services had--_Potential_.

In his own mind, Colonel Fennister spelled the word with an upper case
_P_, and put the word in italics. It was, to him, a more potent word
than any other in the Universe.

Potential.

_Potential!_

[Illustration]

Because the Space Service of the United Earth had more potential than
any other Service on Earth. How many seas were there for the Sea Service
to sail? How much land could the Land Service march over? How many
atmospheres were there for the Air Service to conquer?

Not for any of those questions was there an accurate answer, but for
each of those questions, the answer had a limit. But how much space was
there for the Space Service to conquer?

Colonel Fennister was not a proud man. He was not an arrogant man. But
he _did_ have a sense of destiny; he _did_ have a feeling that the human
race was going somewhere, and he did not intend that that feeling should
become totally lost to humanity.

Potential.

Definition: _Potential; that which has a possibility of coming into
existence._

No, more than that. That which has a--

       *       *       *       *       *

He jerked his mind away suddenly from the thoughts which had crowded
into his forebrain.

What were the chances that the first expedition to Alphegar IV would
succeed? What were the chances that it would fail?

And (Fennister grinned grimly to himself) what good did it do to
calculate chances after the event had happened?

Surrounding the compound had been a double-ply, heavy-gauge, woven
fence. It was guaranteed to be able to stop a diplodocus in full charge;
the electric potential (_potential!_ That word again!) great enough to
carbonize anything smaller than a blue whale. No animal on Alphegar IV
could possibly get through it.

And none had.

Trouble was, no one had thought of being attacked by something immensely
greater than a blue whale, especially since there was no animal larger
than a small rhino on the whole planet. Who, after all, could have
expected an attack by a blind, uncaring colossus--a monster that had
already been dying before it made its attack?

Because no one had thought of the forest.

The fact that the atmospheric potential--the voltage and even the
amperage difference between the low-hanging clouds and the ground
below--was immensely greater than that of Earth, that had already been
determined. But the compound and the defenses surrounding it had already
been compensated for that factor.

Who could have thought that a single lightning stroke through one of the
tremendous, twelve-hundred-foot trees that surrounded the compound could
have felled it? Who could have predicted that it would topple toward the
compound itself?

That it would have been burning--that was something that could have been
guaranteed, had the idea of the original toppling been considered.
Especially after the gigantic wooden life-thing had smashed across the
double-ply fence, thereby adding man-made energy to its already
powerful bulk and blazing surface.

But--that it would have fallen across Storage Shed Number One? Was
_that_ predictable?

Fennister shook his head slowly. No. It wasn't. The accident was simply
that--an accident. No one was to blame; no one was responsible.

Except Fennister. _He_ was responsible. Not for the accident, but for
the personnel of the expedition. He was the Military Officer; he was the
Man In Charge of Fending Off Attack.

And he had failed.

Because that huge, blazing, stricken tree had toppled majestically down
from the sky, crashing through its smaller brethren, to come to rest on
Storage Shed Number One, thereby totally destroying the majority of the
food supply.

There were eighty-five men on Alphegar IV, and they would have to wait
another six months before the relief ship came.

And they didn't have food enough to make it, now that their reserve had
been destroyed.

Fennister growled something under his breath.

"What?" asked Major Grodski, rather surprised at his superior's tone.

"I said: 'Water, water, everywhere--', that's what I said."

Major Grodski looked around him at the lush forest which surrounded the
double-ply fence of the compound.

"Yeah," he said. "'Nor any drop to drink.' But I wish one of those
boards had shrunk--say, maybe, a couple hundred feet."

"I'm going back to my quarters," Fennister said. "I'll be checking with
the civilian personnel. Let me know the total damage, will you?"

The major nodded. "I'll let you know, sir. Don't expect good news."

"I won't," said Colonel Fennister, as he turned.

       *       *       *       *       *

The colonel let his plump bulk sag forward in his chair, and he covered
his hands with his eyes. "I can imagine all kinds of catastrophes," he
said, with a kind of hysterical glumness, "but this has them all beat."

Dr. Pilar stroked his, short, gray, carefully cultivated beard. "I'm
afraid I don't understand. We could all have been killed."

The colonel peeked one out from between the first and second fingers of
his right hand. "You think starving to death is cleaner than fire?"

Pilar shook his head slowly. "Of course not. I'm just not certain that
we'll all die--that's all."

Colonel Fennister dropped his hands to the surface of his metal desk. "I
see," he said dryly. "Where there's life, there's hope. Right? All
right, I agree with you." He waved his hand around, in an
all-encompassing gesture. "Somewhere out there, we may find food. But
don't you see that this puts us in the Siege Position?"

Dr. Francis Pilar frowned. His thick salt-and-pepper brows rumpled in a
look of puzzlement. "Siege Position? I'm afraid--"

Fennister gestured with one hand and leaned back in his chair, looking
at the scientist across from him. "I'm sorry," he said. "I've let my
humiliation get the better of me." He clipped his upper lip between his
teeth until his lower incisors were brushed by his crisp, military
mustache, and held it there for a moment before he spoke.

"The Siege Position is one that no military commander of any cerebral
magnitude whatever allows himself to get into. It is as old as Mankind,
and a great deal stupider. It is the position of a beleaguered group
which lacks one simple essential to keep them alive until help comes.

"A fighting outfit, suppose, has enough ammunition to stand off two more
attacks; but they know that there will be reinforcements within four
days. Unfortunately, the enemy can attack _more than twice_ before help
comes. Help will come too late.

"Or, it could be that they have enough water to last a week, but help
won't come for a month.

"You follow me, I'm sure. The point, in so far as it concerns us, is
that we have food for about a month, but we won't get help before six
months have passed. We know help is coming, but we won't be alive to see
it."

Then his eyes lit up in a kind of half hope. "Unless the native flora--"

But even before he finished, he could see the look in Dr. Pilar's eyes.

       *       *       *       *       *

Broderick MacNeil was a sick man. The medical officers of the Space
Service did not agree with him _in toto_, but MacNeil was in a position
to know more about his own state of health than the doctors, because it
was, after all, he himself who was sick.

Rarely, of course, did he draw the attention of the medical officers to
his ever-fluctuating assortment of aches, pains, signs, symptoms,
malaises, and malfunctions. After all, it wouldn't do for him to be
released from the Service on a Medical Discharge. No, he would suffer in
silence for the sake of his chosen career--which, apparently, was to be
a permanent Spaceman 2nd Class.

Broderick MacNeil had never seen his medical record, and therefore did
not know that, aside from mention of the normal slight defects which
every human body possesses, the only note on the records was one which
said: "Slight tendency toward hypochondria, compensated for by tendency
to immerse self in job at hand. According to psych tests, he can
competently handle positions up to Enlisted Space Officer 3rd Class, but
positions of ESO/2 and above should be carefully considered. (See Psych
Rept. Intelligence Sectn.)"

But, if MacNeil did not know what the medics thought of him, neither did
the medics know what he thought of them. Nor did they know that MacNeil
carried a secret supply of his own personal palliatives, purgatives and
poly-purpose pills. He kept them carefully concealed in a small section
of his space locker, and had labeled them all as various vitamin
mixtures, which made them seem perfectly legal, and which was not _too_
dishonest, since many of them _were_ vitamins.

On the morning after the fire, he heaved his well-muscled bulk out of
bed and scratched his scalp through the close-cropped brown hair that
covered his squarish skull. He did not feel well, and that was a fact.
Of course, he had been up half the night fighting the blaze, and that
hadn't helped any. He fancied he had a bit of a headache, and his nerves
seemed a little jangled. His insides were probably in their usual balky
state. He sighed, wished he were in better health, and glanced around at
the other members of the company as they rose grumpily from their beds.

He sighed again, opened his locker, took out his depilator, and ran it
quickly over his face. Then, from his assortment of bottles, he began
picking over his morning dosage. Vitamins, of course; got to keep plenty
of vitamins in the system, or it goes all to pot on you. A, B_1, B_2,
B_12, C, ... and on down the alphabet and past it to A-G. All-purpose
mineral capsules, presumably containing every element useful to the
human body and possibly a couple that weren't. Two APC capsules.
(Aspirin-Phenacetin-Caffeine. He liked the way those words sounded; very
medicinal.) A milk-of-magnesia tablet, just in case. A couple of
patent-mixture pills that were supposed to increase the bile flow.
(MacNeil wasn't quite sure what bile was, but he _was_ quite sure that
its increased flow would work wonders within.) A largish tablet of
sodium bicarbonate to combat excess gastric acidity--obviously a
_horrible_ condition, whatever it was. He topped it all off with a
football-shaped capsule containing Liquid Glandolene--"_Guards the
system against glandular imbalance!_"--and felt himself ready to face
the day. At least, until breakfast.

He slipped several bottles into his belt-pak after he had put on his
field uniform, so that he could get at them at mealtimes, and trudged
out toward the mess hall to the meager breakfast that awaited him.

       *       *       *       *       *

"Specifically," said Colonel Fennister, "what we want to know is: What
are our chances of staying alive until the relief ship comes?"

He and most of the other officers were still groggy-eyed, having had too
much to do to even get an hour's sleep the night before. Only the
phlegmatic Major Grodski looked normal; his eyes were always about half
closed.

Captains Jones and Bellwether, in charge of A and B Companies
respectively, and their lieutenants, Mawkey and Yutang, all looked grim
and irritable.

The civilian components of the policy group looked not one whit better.
Dr. Pilar had been worriedly rubbing at his face, so that his normally
neat beard had begun to take on the appearance of a ruptured mohair
sofa; Dr. Petrelli, the lean, waspish chemist, was nervously trimming
his fingernails with his teeth: and the M.D., Dr. Smathers, had a
hangdog expression on his pudgy face and had begun drumming his fingers
in a staccato tattoo on his round belly.

Dr. Pilar tapped a stack of papers that lay before him on the long table
at which they were all seated. "I have Major Grodski's report on the
remaining food. There is not enough for all of us to live, even on the
most extended rations. Only the strongest will survive."

Colonel Fennister scowled. "You mean to imply that we'll be fighting
over the food like animals before this is over? The discipline of the
Space Service--"

His voice was angry, but Dr. Pilar cut him off. "It may come to
fighting, colonel, but, even if perfect discipline is maintained, what I
say will still be true. Some will die early, leaving more food for the
remaining men. It has been a long time since anything like this has
happened on Earth, but it is not unknown in the Space Service annals."

The colonel pursed his lips and kept his silence. He knew that what the
biologist said was true.

"The trouble is," said Petrelli snappishly, "that we are starving in the
midst of plenty. We are like men marooned in the middle of an ocean with
no water; the water is there, but it's undrinkable."

"That's what I wanted to get at," said Colonel Fennister. "Is there any
chance at all that we'll find an edible plant or animal on this planet?"

The three scientists said nothing, as if each were waiting for one of
the others to speak.

       *       *       *       *       *

All life thus far found in the galaxy had had a carbon-hydrogen-oxygen
base. Nobody'd yet found any silicon based life, although a good many
organisms used the element. No one yet had found a planet with a halogen
atmosphere, and, although there might be weird forms of life at the
bottom of the soupy atmospheres of the methane-ammonia giants, no brave
soul had ever gone down to see--at least, not on purpose, and no
information had ever come back.

But such esoteric combinations are not at all necessary for the
postulation of wildly variant life forms. Earth itself was prolific in
its variations; Earthlike planets were equally inventive. Carbon,
hydrogen, and oxygen, plus varying proportions of phosphorus, potassium,
iodine, nitrogen, sulfur, calcium, iron, magnesium, manganese, and
strontium, plus a smattering of trace elements, seem to be able to cook
up all kinds of life under the strangest imaginable conditions.

Alphegar IV was no different than any other Earth-type planet in that
respect. It had a plant-dominated ecology; the land areas were covered
with gigantic trees that could best be described as crosses between a
California sequoia and a cycad, although such a description would have
made a botanist sneer and throw up his hands. There were enough smaller
animals to keep the oxygen-carbon-dioxide cycle nicely balanced, but the
animals had not evolved anything larger than a rat, for some reason. Of
course, the sea had evolved some pretty huge monsters, but the camp of
the expedition was located a long way from the sea, so there was no
worry from that quarter.

At the time, however, the members of the expedition didn't know any of
that information for sure. The probe teams had made spot checks and
taken random samples, but it was up to the First Analytical Expedition
to make sure of everything.

And this much they had discovered: The plants of Alphegar IV had a nasty
habit of killing test animals.

       *       *       *       *       *

"Of course," said Dr. Pilar, "we haven't tested every plant yet. We may
come across something."

"What is it that kills the animals?" asked young Captain Bellwether.

"Poison," said Major Grodski.

Pilar ignored him. "Different things. Most of them we haven't been able
to check thoroughly. We found some vines that were heavily laced with
cyanide, and there were recognizable alkaloids in several of the shrubs,
but most of them are not that direct. Like Earth plants, they vary from
family to family; the deadly nightshade is related to both the tobacco
plant and the tomato."

He paused a moment, scratching thoughtfully at his beard.

"Tell you what; let's go over to the lab, and I'll show you what we've
found so far."

Colonel Fennister nodded. He was a military man, and he wasn't too sure
that the scientists' explanations would be very clear, but if there was
information to be had, he might as well make the most of it.

       *       *       *       *       *

SM/2 Broderick MacNeil kept a firm grip on his blast rifle and looked
around at the surrounding jungle, meanwhile thanking whatever gods there
were that he hadn't been put on the fence-mending detail. Not that he
objected violently to work, but he preferred to be out here in the
forest just now. Breakfast hadn't been exactly filling, and he was
hungry.

Besides, this was his pet detail, and he liked it. He had been going out
with the technicians ever since the base had been finished, a couple of
weeks before, and he was used to the work. The biotechnicians came out
to gather specimens, and it was his job, along with four others, to
guard them--make sure that no wild animal got them while they were going
about their duties. It was a simple job, and one well suited to
MacNeil's capacities.

He kept an eye on the technicians. They were working on a bush of some
kind that had little thorny-looking nuts on it, clipping bits off here
and there. He wasn't at all sure what they did with all those little
pieces and bits, but that was none of his business, anyway. Let the
brains take care of that stuff; his job was to make sure they weren't
interrupted in whatever it was they were doing. After watching the three
technicians in total incomprehension for a minute or so, he turned his
attention to the surrounding forest. But he was looking for a plant, not
an animal.

And he finally saw what he was looking for.

The technicians paid him no attention. They rarely did. They had their
job, and he had his. Of course, he didn't want to be caught breaking
regulations, but he knew how to avoid that catastrophe. He walked
casually toward the tree, as though he were only slightly interested in
it.

He didn't know what the name of the tree was. He'd asked a technician
once, and the tech had said that the tree didn't have any name yet.
Personally, MacNeil thought it was silly for a thing not to have a name.
Hell, _everything_ had a name.

But, if they didn't want to tell him what it was, that was all right
with him, too. He called it a banana-pear tree.

Because that's what the fruit reminded him of.

The fruit that hung from the tree were six or eight inches long, fat in
the middle, and tapering at both ends. The skin was a pale chartreuse in
color, with heliotrope spots.

[Illustration]

MacNeil remembered the first time he'd seen one, the time he'd asked the
tech what its name was. The tech had been picking some of them and
putting them into plastic bags, and the faint spark of MacNeil's dim
curiosity had been brought to feebly flickering life.

"Hey, Doc," he'd said, "whatcha gonna do with them things?"

"Take 'em to the lab," said the technician, engrossed in his work.

MacNeil had digested that carefully. "Yeah?" he'd said at last. "What
for?"

The technician had sighed and popped another fruit into a bag. He had
attempted to explain things to Broderick MacNeil before and given it up
as a bad job. "We just feed 'em to the monkeys, Mac, that's all."

"Oh," said Broderick MacNeil.

Well, that made sense, anyhow. Monkeys got to eat _something_, don't
they? Sure. And he had gazed at the fruit in interest.

Fresh fruit was something MacNeil missed. He'd heard that fresh fruit
was necessary for health, and on Earth he'd always made sure that he had
plenty of it. He didn't want to get sick. But they didn't ship fresh
fruit on an interstellar expedition, and MacNeil had felt vaguely
apprehensive about the lack.

Now, however, his problems were solved. He knew that it was strictly
against regulations to eat native fruit until the brass said so, but
that didn't worry him too much. He'd heard somewhere that a man can eat
anything a monkey can, so he wasn't worried about it. So he'd tried one.
It tasted fine, something like a pear and something like a banana, and
different from either. It was just fine.

Since then, he'd managed to eat a couple every day, so's to get his
fresh fruit. It kept him healthy. Today, though, he needed more than
just health; he was hungry, and the banana-pears looked singularly
tempting.

When he reached the tree, he turned casually around to see if any of the
others were watching. They weren't, but he kept his eye on them while he
picked several of the fruit. Then he turned carefully around, and, with
his back to the others, masking his movements with his own body, he
began to munch contentedly on the crisp flesh of the banana-pears.

       *       *       *       *       *

"Now, take this one, for instance," said Dr. Pilar. He was holding up a
native fruit. It bulged in the middle, and had a chartreuse rind with
heliotrope spots on it. "It's a very good example of exactly what we're
up against. Ever since we discovered this particular fruit, we've been
interested in it because the analyses show that it should be an
excellent source of basic food elements. Presumably, it even tastes
good; our monkeys seemed to like it."

"What's the matter with it, then?" asked Major Grodski, eying the fruit
with sleepy curiosity.

Dr. Pilar gave the thing a wry look and put it back in the specimen bag.
"Except for the fact that it has killed every one of our test
specimens, we don't know what's wrong with it."

Colonel Fennister looked around the laboratory at the cages full of
chittering animals--monkeys, white mice, rats, guinea pigs, hamsters,
and the others. Then he looked back at the scientist. "Don't you know
what killed them?"

Pilar didn't answer; instead, he glanced at Dr. Smathers, the physician.

Smathers steepled his fingers over his abdomen and rubbed his fingertips
together. "We're not sure. Thus far, it looks as though death was caused
by oxygen starvation in the tissues."

"Some kind of anemia?" hazarded the colonel.

Smathers frowned. "The end results are similar, but there is no drop in
the hemoglobin--in fact, it seems to rise a little. We're still
investigating that. We haven't got all the answers yet, by any means,
but since we don't quite know what to look for, we're rather hampered."

The colonel nodded slowly. "Lack of equipment?"

"Pretty much so," admitted Dr. Smathers. "Remember, we're just here for
preliminary investigation. When the ship brings in more men and
equipment--"

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."

[Illustration]

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."

Silently and solemnly, the chemist handed him the Epsom salts.


THE END

  +--------------------------------------------------------------+
  |                Transcriber's Note and Errata                 |
  |                                                              |
  | This etext was produced from Astounding Science Fiction, May |
  | 1959. Extensive research did not uncover any evidence that   |
  | the U.S. copyright on this publication was renewed.          |
  |                                                              |
  | The following typographical errors were corrected:           |
  |                                                              |
  |                |Error         |Correction   |                |
  |                |catastrophies |catastrophes |                |
  |                |Phenacitin    |Phenacetin   |                |
  |                |Caffiene      |Caffeine     |                |
  |                |stacatto      |staccato     |                |
  |                |phosphorpus   |phosphorus   |                |
  |                |charteuse     |chartreuse   |                |
  |                |dizzness      |dizziness    |                |
  |                |MacNeal       |MacNeil      |                |
  |                                                              |
  | A few subscripted numbers have been formatted preceded by an |
  | underscore, e.g., B_12.                                      |
  +--------------------------------------------------------------+





End of Project Gutenberg's Cum Grano Salis, by Gordon Randall Garrett