"Sure. What else can it be?"
"Mr. Craig," the psychologist said slowly, "you have my authorization for you to return to Terra as a private citizen of that planet. You will be given a very liberal supply of PON—which you will definitely need. Good luck. You'll need that too."
On the eighth day, two attendants, who showed the effects of massive doses of PON to protect themselves from the centrifugal force, had to carry a man out of the tank. Many others asked to be removed, begged to be allowed to withdraw their resignations.
"The twelfth day is the worst," a grizzled spaceman told Craig. "That's when the best of 'em want out."
Craig clenched the iron rung of his bed and struggled to bring the old man's face into focus.
"How ... how do they know when you ought ... to come out?" he asked between waves of nausea.
"Blood pressure. They get you just before you go into shock."
"How can they tell?" Craig fought down his growing panic. "I can't."
"That strap around your belly. You mean you ain't noticed it?"