le they were awake. Yet, the most prominent
pattern is the delta rhythm that is universally associated with sleep
and some types of damage to the brain."

"Are there any other signs of physical damage?" Hartson Brant asked.

"No. All tests are negative. Spinal taps show no concussion, and there
is no evidence of trauma of any kind other than psychic. Yet, the
delta rhythms persist. In the one case where we have an EEG taken
before the--incidents, let's call them--the pattern is entirely
different. The scientist had a pattern of a well-known type which
bears no resemblance to the EEG taken after the incident."

Dr. Morrison leaned forward. "What is your conclusion?"

"That our mysterious enemy has somehow caused damage of an unknown
kind, by remote means. And that can mean only one thing: The damage
was caused electronically, probably by transmission through the air."

"Incredible," Weiss muttered, and the sentiment was reflected in the
astonished gasps of the others.

"Let's consider the implications of Parnell's statement," Hartson
Brant said slowly. "If he is correct, then the enemy has devised a
means for causing brain disruption in an individual. A transmitted
signal would inevitably strike countless others; there can be no such
thing as a beam of radiation that strikes one person at a distance
while missing all others. Therefore, this beam must affect only one
person among many."

"But how can a beam be tuned to one person?" Rick asked.

"I don't know, Rick." Hartson Brant turned to Winston. "Do you?"

"No. I have only a hypothesis, and one so far afield from what we know
of the brain today that I even hesitate to suggest it. Let me ask a
question. If the enemy could have access to the brain pattern of an
individual--and remember such patterns are no more similar than
fingerprints--could the enemy then transmit a signal that would affect
only that pattern?"

Julius Weiss objected. "The supposition is based on scientific
knowledge that does not exist."

"So far as we know," Dr. Morrison added.

Parnell Winston held up his hands. "I'm as aware as any of you that
the hypothesis assumes a knowledge of the brain that is incredibly
far advanced. But let us consider the evidence. The three scientists
who have fallen victim show the same signs of brain damage.
Investigation indicates that they were different types who probably
had dissimilar patterns. We also have the special case of Dr. Marks,
who was drugg