"This," said Calhoun, "is not a history of your own case. When did you develop the disease ... whatever it may be?"
"Don't you know what it is?" asked Helen hopelessly.
"Not yet," admitted Calhoun. "I've very little information. I'm trying to get more now."
What other information he had he'd gathered from a newly dead man in a field some miles away. He did not mention that at this moment.
The girl went on, exhaustedly. The first symptom was listlessness, of which the victim was unconscious. One could pull out of it with an effort, but one wasn't aware that anything was wrong. The listlessness progressed. One could realize it only by recognizing the more urgent, more violent effort needed to pay attention, and the discovery of weakness when one tried to act. One did not feel discomfort—not even hunger or thirst. One had to summon increasing resolution even to become aware of the need to do anything at all.
The symptoms were singularly like those of a man too long at too high an altitude without oxygen. They were even more like those of a man in a non-pressurized flier whose oxygen supply has been cut off. But such a man would pass out without realizing that he was slipping into unconsciousness. On Maris III the process was infinitely gradual. It was a matter of two weeks or more.
"I'd been infected before we ran away," she said drearily. "I didn't know it then. Now I know I've a few more days of being able to think and act ... if I try hard enough. But it'll be less and less each day. Then I'll stop being able to try."
Calhoun watched the tiny recorder roll its multiple-channel tape from one spool to the other as she talked.
"You had energy enough to try to kill me," he observed.