ing atmosphere.

The human mind can insulate itself, for a time, against the destructive
effects 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's
mind--and thus his flesh--is heir to. As long as a mind is capable of
changing from one to another, to rotate its crops, so to speak, the
insulation will remain effective, and the mind will remain undamaged.
But any single emotional element, held for too long, will break down the
resistance 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 the
other coming into play, can love be endured for any great length of
time.

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

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

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

_Psychokinesis_ is defined as the ability of a human mind to move, no
matter how slightly, a physical object by means of psionic application
alone. In theory, then, one could move planets, stars, even whole
galaxies by thought alone. But, in physical terms, the limit is easily
seen. Physically, it would be theoretically possible to destroy the sun
if one had enough atomic energy available, but that would require the
energy of another sun--or more. And, at that point, the Law of
Diminishing Returns comes into operation. If you do