dy's really pretty stupid, it's hard to adjust to the idea
that maybe he _isn't_, all of a sudden. We should have been much more
suspicious of Dr. Tarnier's tests. It's true they weren't designed for
Venusians, but they were designed to assess intelligence, and
intelligence isn't a quality that's influenced by environment or
species. It's either there or it isn't, and the good Doctor told us
unequivocally that it was there."

"But their behavior."

"Even that should have tipped us off. There is a very fine line dividing
incredible stupidity and incredible _stubbornness_. It's often a tough
differential to make. I didn't spot it until I found them wolfing down
the tetracycline capsules in my samples case. Then I began to see the
implications. Those Mud-pups were stubbornly and tenaciously determined
to drive the Piper Venusian Installation off Venus permanently, by fair
means or foul. They didn't care how it got off--they just wanted it
off."

"But why? We weren't hurting them. There's plenty of mud on Venus."

"Ah--but not so much of the blue-gray stuff we were after, perhaps.
Suppose a space ship settled down in a wheatfield in Kansas along about
harvest time and started loading wheat into the hold? I suppose the
farmer wouldn't mind too much. After all, there's plenty of vegetation
on Earth--"

"They're _growing_ the stuff?"

"For all they're worth," said Kielland. "Lord knows what sort of
metabolism uses tetracycline for food--but they are growing mud that
yields an incredibly rich concentration of antibiotic ... their native
food. They grow it, harvest it, live on it. Even the way they shake
whenever they come out of the mud is a giveaway--what better way to
seed their crop far and wide? We were mining away their staff of life,
my friend. You really couldn't blame them for objecting."

"Well, if they think they can drive us off that way, they're going to
have to get that brilliant intelligence of theirs into action," Simpson
said ominously. "We'll bring enough equipment down there to mine them
out of house and home."

"Why?" said Kielland. "After all, they're mining it themselves a lot
more efficiently than we could ever do it. And with Piper warehouses
back on Earth full of old, useless antibiotics that they can't sell for
peanuts? No, I don't think we'll mine anything when a simple trade
arrangement will do just as well." He sank back in his cot, staring
dreamily through the port as the huge orbital tran