The Hostage of Zir by L. Sprague de Camp

these came two more freight cars. After a look at the meter-wide gap between his own swaying, yawing car and the next one aft, Reith went back into his own car and handed his sword to Guzmán-Vidal, saying: “Would you please hold this, Santiago? I don’t want to jump to the next car and have this thing trip me up.”
    Reith jumped the gap and continued into the Krishnan-occupied car. He found Strachan on one of the seats, smoking a powerful Krishnan cigar and talking fluent Durou with one of his workmen.
    “Ahoy, laddie!” said Strachan. “Not quite the Royal Scot, is it? But give ’em time. The Industrial Revolution’s on its way. Come back in a hundred years and you won’t know the planet. They’ll probably go through an automobile age, the same as we did, until their petroleum gives out. That is, if they have petroleum.”
    “Won’t that lead to a lot of turmoil, revolution, and so on?”
    Strachan shrugged. “Belike, but what can we do? Once they know it can be done—and we’ve shown them it can by example—they’ll not rest until they’ve done it, too. It does no good to warn them against Terran mistakes. Still and on, they’re an uncoly volatile, scrappy lot, so a little more violence won’t make much difference.”
    “Ken,” said Reith, “you were going to tell me about these characters out in Zir, the Dasht and the Witch.” He had to shout to be heard above the clatter.
    “Weel, now—hold on; we’re going into a siding.”
    As the train struck a reverse curve, Reith grabbed a seat back to keep from being thrown into a Krishnan’s lap. Trainmen bustled back and forth. Brake shoes ground, and the train slowed to a halt. They stood on a double-tracked section.
    “What’s this?” asked Reith.
    “We’re stopping for two purposes; namely, to wait for the regular eastbound daily from Jizorg to go by on the main track, and to eat our lunch.”
    “I wondered how we’d eat with these things bucking like broncos. Don’t Krishnan railroads have double-tracked lines?”
    “Not yet; traffic’s not dense enough. Tell your folk to get off and stretch if they like. We shan’t go off without them.”
    Reith hurried back to his own car and handed out the box lunches piled on one of the seats. Presently his tourists were all sitting or standing beside the train, eating and drinking. Up forward, the bishtars had been unhitched and guided to the edge of the forest There they fell to feeding. Each animal grabbed a huge mass of many-colored vegetation in the fork of its cleft trunk, wrenched it loose, and stuffed it into its cavernous maw.
    “Sheugh, man!” came a sudden shout from Strachan. “Watch that stuff!”
    Reith looked around. Strachan was speaking to Professor Mulroy, who had been about to pick a sprig of a plant with leaves of a striking pattern of black and white stripes. Strachan explained: “That’s the sha’pir, or zebra weed if you prefer. It works like your American poison ivy. Only, in accord with the principle that everything nasty here is twice as nasty, it comes on twice as quick, itches twice as bad, and lasts twice as long.
    “When Siggy and I were working in Suruskand, one hot day he took a dip in a pool in a river and then found he had nocht to dry himself with. So he tried to dry his hands, face, and other parts with these leaves. He was laid up so long that it cost us the bonus we’d have earned for finishing the job ahead of time.”
    “My word!” said the professor. “I am exceedingly grateful to you, Mr. Strachan. This plant looks interesting. It has evidently evolved a warning coloration, analogous to that of a Terran hornet. I don’t suppose there’s a book on the poisonous plants of Krishna?”
    “Not that I know. A couple of years ago, there was a human botanist in Suruskand studying the plants. But the poor birkie went out without an escort once too often, and a yeki ate him.”
    “Dear me!” said Mulroy. Several tourists added exclamations. “I trust