ferred relaxation to exercise.

But he did take his feet from the couch and lift himself to a sitting
position as Candron entered. And, at the same time, the one resemblance
between Taggert and Candron manifested itself--a warm, truly human
smile.

"Spence," he said warmly, "you look as though you were bored. Want a
job?"

"No," said Candron, "but I'll take it. Who do I kill?"

"Nobody, unless you absolutely have to," said Taggert.

Spencer Candron understood. The one thing that characterized the real
members of The Society for Mystical and Metaphysical Research--not the
"front" members, like Balfour and Mrs. Jesser, not the hundreds of
"honorable" members who constituted the crackpot portion of the
membership, but the real core of the group--the thing that characterized
them could be summed up in one word: _understanding_. Without that one
essential property, no human mind can be completely free. Unless a human
mind is capable of understanding the only forces that can be pitted
against it--the forces of other human minds--that mind cannot avail
itself of the power that lies within it.

Of course, it is elementary that such understanding must also apply to
oneself. Understanding of self must come before understanding of others.
_Total_ understanding is not necessary--indeed, utter totality is very
likely impossible to any human mind. But the greater the understanding,
the freer the mind, and, at a point which might be called the "critical
point," certain abilities inherent in the individual human mind become
controllable. A change, not only in quantity, but in quality, occurs.

A cube of ice in a glass of water at zero degrees Celsius exhibits
certain properties and performs certain actions at its surface. Some of
the molecules drift away, to become one with the liquid. Other molecules
from the liquid become attached to the crystalline ice. But, the ice
cube remains essentially an entity. Over a period of time, it may change
slowly, since dissolution takes place faster than crystallization at the
corners of the cube. Eventually, the cube will become a sphere, or
something very closely approximating it. But the change is slow, and,
once it reaches that state, the situation becomes static.

But, if you add heat, more and more and more, the ice cube will change,
not only its shape, but its state. What it was previously capable of
doing only slightly and impermanently, it can now do completely. The
critical point h