"Now," Dr. O'Connor said. He selected a single lead, apparently, Malone thought, at random. "This electrode--" "Just a moment, Doctor," Burris said. He was eyeing the machine with a combination of suspicion and awe. "A while back you mentioned something about 'outside influences.' Just what, specifically, does that mean?" With some regret, Dr. O'Connor dropped the lead. "Telepathy," he said. "By outside influences, I meant influences on the mind, such as telepathy or mind-reading of some nature." "I see," Burris said. "You can detect a telepath with this machine." "I'm afraid--" "Well, some kind of a mind-reader anyhow," Burris said. "We won't quarrel about terms." "Certainly not," Dr. O'Connor said. The smile he turned on Burris was as cold and empty as the inside of Orbital Station One. "What I meant was--if you will permit me to continue--that we cannot detect any sort of telepathy or mind-reader with this device. To be frank, I very much wish that we could; it would make everything a great deal simpler. However, the laws of psionics don't seem to operate that way." "Well, then," Burris said, "what does the thing do?" His face wore a mask of confusion. Momentarily, Malone felt sorry for his chief. He could remember how he'd felt, himself, when that law professor had come up 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."