ppose, for instance,
that you become aware of a runaway car bearing down on you.

"Your heartbeat speeds up, your adrenalin output increases, your sight
sharpens, your sensitivity to pain drops--it's all preparation for
fight or flight. Even without obvious physical necessity the same
thing can happen on a lesser scale--for example when you read an
exciting story. And psychotics, especially hysterics, can produce some
of the damnedest physiological symptoms you ever saw."

"I begin to understand," she whispered.

"Rage or fear brings abnormal strength and fast reaction. But the
psychotic can do more than that. He can show physical symptoms like
burns, stigmata or--if female--false pregnancy. Sometimes he becomes
wholly insensitive in some part of his body via a nerve bloc.
Bleeding can start or stop without apparent cause. He can go into a
coma or he can stay awake for days without getting sleepy. He can--"

"Read minds?" It was a defiance.

"Not that I know of." Simon chuckled. "But human sense organs are
amazingly good. It only takes three or four quanta to stimulate the
visual purple--a little more actually because of absorption by the
eyeball itself. There have been hysterics who could hear a watch
ticking twenty feet away that the normal person could not hear at one
foot. And so on.

"There are excellent reasons why the threshold of perception is
relatively high in ordinary people--the stimuli of usual conditions
would be blinding and deafening, unendurable, if there weren't a
defense." He grimaced. "I _know_!"

"But the telepathy?" Elena persisted.

"It's been done before," he said. "Some apparent cases of mindreading
in the last century were shown to be due to extremely acute hearing.
Most people sub-vocalize their surface thoughts. With a little
practice a person who can hear those vibrations can learn to interpret
them. That's all." He smiled with one side of his mouth. "If you want
to hide your thoughts from me just break that habit, Elena."

She looked at him with an emotion he could not quite recognize. "I
see," she breathed. "And your memory must be perfect too, if you can
pull any datum out of the subconscious. And you can--do everything,
can't you?"

"No," he said. "I'm only a test case. They've learned a great deal by
observing me but the only thing that makes me unusual is that I have
conscious control of certain normally subconscious and involuntary
functions. Not all of them by a long sho