see that the doctorate youclaim is not for studies in the field of physics. You're not here toworm things out of me by discussing my work talking shop. What is it,_Doctor_ Wan?"

  "I am a psychologist." Candron said. He knew that the monitors watchingthe screens and listening to the conversation were recording everything.He knew that they shouldn't be suspicious yet. But if the real GeneralSoong should decide to check on what his important guest was doing....

  "A psychologist," Ch'ien repeated in a monotone. "I see."

  "Yes. Now, will you stand, or do I have to ask the guards to lift you toyour feet?"

  James Ch'ien recognized the inevitable, so he stood. But there was awary expression in his black eyes. He was not a tall man; he stoodnearly an inch shorter than Candron himself.

  "You have nothing to fear, Dr. Ch'ien," Candron said smoothly. "I merelywish to test a few of your reactions. We do not wish to hurt you." Heput his hands on the other man's shoulders, and positioned him. "There,"he said. "Now. Look to the left."

  "Hypnosis, eh?" Ch'ien said with a grim smile. "All right. Go ahead." Helooked to his left.

  "Not with your head," Candron said calmly. "Face me and look to the leftwith your eyes."

  Ch'ien did so, saying: "I'm afraid you'll have to use drugs after all,Dr. Wan. I will not be hypnotized."

  "I have no intention of hypnotizing you. Now look to the right."

  Ch'ien obeyed.

  Candron's right hand was at his side, and his left hand was toying witha button on his coat. "Now up," he said.

  Dr. James Ch'ien rolled his eyeballs upward.

  Candron had already taken a deep breath. Now he acted. His right handballed into a fist and arced upwards in a crashing uppercut to Ch'ien'sjaw. At almost the same time, he jerked the button off his coat, crackedit with his fingers along the special fissure line, and threw it to thefloor.

  As the little bomb spewed forth unbelievable amounts of ultra-finelydivided carbon in a dense black cloud of smoke, Candron threw both armsaround the collapsing physicist, ignoring the pain in the knuckles ofhis right hand. The smoke cloud billowed around them, darkening the roomand obscuring the view from the monitor screens that were watching them.Candron knew that the guards were acting now; he knew that the bigMongols outside were already inserting the key in the door and insertingtheir nose plugs; he knew that the men in the monitor room had hit analarm button and had already begun to flood the room with sleep gas. Buthe paid no attention to these things.

  Instead, he became homesick.

  Home. It was a little place he knew and loved. He could no longer standthe alien environment around him; it was repugnant, repelling. All hecould think of was a little room, a familiar room, a beloved room. Heknew the cracks in its ceiling, the feel of the varnish on the homelylittle desk, the touch of the worn carpet against his feet, the verysmell of the air itself. And he loved them and longed for them with allthe emotional power that was in him.

  And suddenly the darkness of the smoke-filled prison apartment was gone.

  Spencer Candron stood in the middle of the little hotel room he hadrented early that morning. In his arms, he held the unconscious figureof Dr. James Ch'ien.

  He gasped for breath, then, with an effort, he stooped, allowed the limpbody of the physicist to collapse over his shoulder, and stood straightagain, carrying the man like a sack of potatoes. He went to the door ofthe room and opened it carefully. The hall was empty. Quickly, he movedoutside, closing the door behind him, and headed toward the stair. Thistime, he dared not trust the elevator shaft. The hotel only boasted oneelevator, and it might be used at any time. Instead, he allowed hisdislike for the stair treads to adjust his weight to a few pounds, andthen ran up them two at a time.

  On the roof of the hotel, he adjusted his emotional state once more, andhe and his sleeping burden drifted off into the night, toward the sea.

  * * * * *

  No mind is infinitely flexible, infinitely malleable, infinitely capableof taking punishment, just as no material substance, howeverconstructed, is capable of absorbing the energies brought to bearagainst it indefinitely.

  A man can hate with a virulent hatred, but unless time is allowed todull and soothe that hatred, the mind holding it will become corrodedand cease to function properly, just as a machine of the finest steelwill become corroded and begin to fail if it is drenched with acid orexposed to the violence of an oxidizing atmosphere.

  The human mind can insulate itself, for a time, against the destructiveeffects of any emotion, be it hatred, greed, despondency, contentment,happiness, pleasure, anger, fear, lust, boredom, euphoria,determination, or any other of the myriads of "ills" that man'smind--and thus his flesh--is heir to. As long as a mind is capable ofchanging from one to another, to rotate its crops, so to speak, theinsulation will remain effective, and the mind will remain undamaged.But any single emotional element, held for too long, will break down theresistance of the natural insulation and begin to damage the mind.

  Even that least virulent of emotions, love, can destroy. The hot,passionate love between new lovers must be modified or it will kill.Only when its many facets can be shifted around, now one and now theother coming into play, can love be endured for any great length oftime.

  Possibly the greatest difference between the sane and the unsane is thatthe sane know when to release a destructive force before it does morethan minimal damage; to modify or eliminate an emotional conditionbefore it becomes a deadly compulsion; to replace one set of conceptswith another when it becomes necessary to do so; to recognize that pointwhen the mind must change its outlook or die. To stop the erosion, inother words, before it becomes so great that it cannot be repaired.

  For the human mind cannot contain any emotion, no matter how weak or howfleeting, without change. And the point at which that change ceases tobe _con_structive and becomes, instead, _de_structive--_that_ is theultimate point beyond which no human mind can go without forcing achange--_any_ change--in itself.

  Spencer Candron knew that. To overuse the psionic powers of the humanmind is as dangerous as overusing morphine or alcohol. There are limitsto mental powers, even as there are limits to physical powers.

  _Psychokinesis_ is defined as the ability of a human mind to move, nomatter how slightly, a physical object by means of psionic applicationalone. In theory, then, one could move planets, stars, even wholegalaxies by thought alone. But, in physical terms, the limit is easilyseen. Physically, it would be theoretically possible to destroy the sunif one had enough atomic energy available, but that would require theenergy of another sun--or more. And, at that point, the Law ofDiminishing Returns comes into operation. If you don't want a bomb toexplode, but the only way to destroy that bomb is by blowing it up withanother bomb of equal power, where is the gain?

  And if the total mental power required to move a planet is greater thanany single human mind can endure--or even greater than the total mentalendurance of a thousand planetsfull of minds, is there any gain?

  There is not, and can never be, a system without limits, and the humanmind is a system which obeys that law.

  None the less, Spencer Candron kept his mind on flight, on repulsion, onmovement, as long as he could. He was perfectly willing to destroy hisown mind for a purpose, but he had no intention of destroying ituselessly. He didn't know how long he kept moving eastward; he had noway of knowing how much distance he had covered nor how long it hadtaken him. But, somewhere out over the smoothly undulating surface ofthe Pacific, he realized that he was approaching his limit. And, a fewseconds later, he detected the presence of men beneath the sea.

  He knew they were due to rise an hour before dawn, but he had no ideahow long that would be. He had lost all track of time. He had beenkeeping his mind on controlling his altitude and motion, and, at thesame time, been careful to see whether Dr. Ch'ien came out of hisunconscious state. Twice more he had had to strike the physicist to keephim out cold, and he didn't want to do it again.

  So, whe
n he sensed the presence of the American submarine beneath thewaves, he sank gratefully into the water, changing the erosive power ofthe emotion that had carried him so far, and relaxing into the simplephysical routine of keeping both himself and Ch'ien afloat.

  By the time the submarine surfaced a dozen yards away, Spencer Candronwas both physically and mentally exhausted. He yelled at the top of hislungs, and then held on to consciousness just long enough to be rescued.

  * * * * *

  "The official story," said Senator Kerotski, "is that an impostor hadtaken Dr. Ch'ien's place before he ever left the United States--" Hegrinned. "At least, the substitution took place before the delegatesreached China. So the 'assassination' was really no assassination atall. Ch'ien was kidnaped here, and a double put in