d
reach for the aspirin from out of his grave.

"Now I'll show you how it works; the main power is cut off but there's
enough juice left in The Brain's system to make this pulsemeter react;
it's even more sensitive than a Geiger-Mueller counter."

He surveyed a big switchboard and picked out an outlet marked "Pons
Varolis for the plug-in." Then snapped a pair of earphones on Lee's
head.

"There," he said "you'll both see and hear what it does in a little
while."

* * * * *

A soft glow slowly spread over the slanting screen on top of the
machine. A crackling as of static entered the earphones and turned into
a low hum. On the left corner of the screen a faint green streak of
luminosity crawled over to the right; its light gained in intensity and
it began to weave and to dance. Simultaneously the hum became articulate
like tickings of a heart only much faster.

"Is that the pulse of The Brain?" Lee asked.

"No," Gus snorted contemptuously. "The Brain isn't even operating.
Nothing moves in The Brain now excepting those ebbing residual currents,
too low in power to agitate anything but the amplifiers built into this
thing. If these were normal operations with a million impulses per
second passing through The Brain you could hear and see as little of the
pulse as of the beatings of a million mosquito wings. In that case the
dial to your right works a reduction-gear, kind of an inverted
stroboscope; that cuts the speed down a hundred-thousand to one and you
just barely see and hear the rhythm of the beat."

"I see."

Fascinated by the dance of the green line Lee said absently, "This
touches upon another question I had in mind; The Brain is expanding,
that is, new cell groups and circuits are constantly being added.
Right?"

"Right."

"I also understand that The Brain is learning all the time. The cerebral
mantle evolves through being worked; its cells enriched by the material
submitted to them for processing; the richer the material, the richer
their yield. Right?"

"Right."

"Okay; then what becomes of the new capacity which is being created by
the adding of new workshops and the increased efficiency of the old
ones? Is there a corresponding expansion of the apperception centers?"

Gus' smiling face suddenly turned serious. There was surprise mingled
with respect in his voice as he said:

"Now there you've hit upon a funny thing, Aussie. I've been wondering
about that mys