with a particularly baffling question in class.

"This machine," Dr. O'Connor said with authority, "detects the slight
variations in mental activity that occur when a person's mind is
_being_ read."

"You mean, if my mind were being read right now--"

"Not right now," Dr. O'Connor said. "You see, the bulk of this machine
is in Nevada; the structure is both too heavy and too delicate for
transport. And there are other qualifications--"

"I meant theoretically," Burris said.

"Theoretically--" Dr. O'Connor began, and smiled
again--"Theoretically, if your mind were being read, this machine
would detect it, supposing that the machine were in operating
condition and all of the other qualifications had been met. You see,
Mr. Burris, no matter how poor a telepath a man may be, he has some
slight ability--even if only very slight--to detect the fact that his
mind is being read."

"You mean, if somebody was reading my mind, I'd know it?" Burris said.
His face showed, Malone realized, that he plainly disbelieved this
statement.

"You would know it," Dr. O'Connor said, "but you would never know you
knew it. To elucidate: in a normal person--like you, for instance, or
even like myself--the state of having one's mind read merely results
in a vague, almost sub-conscious feeling of irritation, something that
could easily be attributed to minor worries, or fluctuations in one's
hormonal balance. The hormonal balance, Mr. Burris, is--"

"Thank you," Burris said with a trace of irritation. "I know what
hormones are."

"Ah. Good," Dr. O'Connor said equably. "In any case, to continue: this
machine interprets those specific feelings as indications that the
mind is being--ah--'eavesdropped' upon."

You could almost see the quotation marks around what Dr. O'Connor
considered slang dropping into place, Malone thought.

"I see," Burris said with a disappointed air. "But what do you mean,
it won't detect a telepath? Have you ever actually worked with a
telepath?"

"Certainly we have," Dr. O'Connor said. "If we hadn't, how would we be
able to tell that the machine was, in fact, indicating the presence of
telepathy? The theoretical state of the art is not, at present,
sufficiently developed to enable us to--"

"I see," Burris said hurriedly. "Only wait a minute."

"Yes?"

"You mean you've actually got a real mind-reader? You've found one?
One that works?"

Dr. O'Connor shook his head sadly. "I'm afraid I should have said, Mr.