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
equip