"I had some workmen clear the weeds out. I intend to replace the air machinery as soon as I can get some new material sent from Terra."
Channing managed to blink. It was an effort. "You had workmen toss the weeds out—" he repeated dully. "The weeds—"
There was silence for a minute, Burbank studied the man in the chair as though Channing were a piece of statuary. Channing was just as motionless. "Channing, man, what ails you—" began Burbank. The sound of Burbank's voice aroused Channing from his shocked condition.
Channing leaped to his feet. He landed on his heels, spun, and snapped at Arden: "Get on the type. Have 'em slap as many oxy-drums on the fastest ship as they've got! Get 'em here at full throttle. Tell 'em to load up the pilot and crew with gravanol and not to spare the horsepower! Scram!"
Arden gasped. She fled from the office.
"Burbank, what did you think an air plant was?" snapped Channing.
"Why, isn't it some sort of purifying machinery?" asked the wondering Director.
"What better purifying machine is there than a plot of grass?" shouted Channing. "Weeds, grass, flowers, trees, alfalfa, wheat, or anything that grows and uses chlorophyll. We breathe oxygen, exhale CO2. Plants inhale CO2, and exude oxygen. An air plant means just that. It is a specialized type of Martian sawgrass that is more efficient than anything else in the system for inhaling dead air and revitalizing it. And you've tossed the weeds out!" Channing snorted in anger. "We've spent years getting that plant so that it will grow just right. It got so good that the CO2 detectors weren't even needed. The balance was so adjusted that they haven't even been turned on for three or four years. They were just another source of unnecessary expense. Why, save for a monthly inspection, that room isn't even opened, so efficient is the Martian sawgrass. We, Burbank, are losing oxygen!"
The Director grew white. "I didn't know," he said.
"Well, you know now. Get on your horse and do something. At least, Burbank, stay out of my way while I do something."