"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.