His audio-visor suddenly flickered and hummed. Who would be calling him? Only someone on Caliban. His father? But why? Unless....
The face rippled onto the screen. His father's face—but it seemed that the face had aged twenty years since the interview short hours before.
"Dirk," the voice said. "Dirk—have you checked your ship?"
He pushed the talk-back. "Yes, dad. There's something ... something that looks like jelly. It's growing. The disinteray doesn't stop it."
"You've got to turn back, Dirk. Nothing will stop that jelly-thing. As long as it gets oxygen, it'll keep growing! You've got to turn back to Caliban."
Dirk's eyes flickered to the gauges on the panel. "There's not enough fuel to get me back to Caliban. I can feel the pull of Terra's solar system already."
The visor went abruptly blank and then Tabor's face replaced his father's on the screen. "Listen to me, Dirk," Tabor said, and the academic hesitancy had been discarded for a terrible urgency. "That stuff in your ship is wild cells. They're the only life on Caliban. Oxygen has a peculiar effect on them. Makes them multiply by geometric progression. Do you understand that?"
"I understand." Dirk's voice was a thing remote from him, apart.
"There's nothing you can do to stop that growth. The disinteray won't help. You've got to get it back to Caliban—out of oxygen."
"I can't. I haven't enough fuel, Tabor." Dirk fought to keep his voice controlled and calm, but he could see already a crystalline ooze seeping under the desk, the filing cabinet. It couldn't be stopped.