cabled to this calculator was fastened about his skull, and he
could no longer see the professor who was lecturing in the
amphitheatre above. But along his body he could see the
group of medical students. They were looking at him with
great interest, too young not to let the human drama interfere
with their technical education.
The professor, however, droned in a purely objective voice.
'The mnemonic eraser can selectively shunt from the brain
any identifiable category of memory, and erase the synaptic
patterns associated with its translation into action. Circulating
memory is disregarded. The machine only locates and shunts
out those energies present as permanent memory. These are
there in part as permanently echoing frequencies in closed
cytoplasmic systems. These systems are in contact with the rest
of the nervous system only during the phenomenon of remem-
brance. Remembrance occurs when, at all the synapses in a
given network 'y', the permanently echoing frequencies are
duplicated as transient circulating frequencies.
'The objective in a total operation of the sort before us
of the personality you wish to extinguish, from the frequen-
cies typical of the other personality present in the brain.'
Major Grey's face, very tired, but still wearing a mask of
adamant reassurance, came into Bill's vision. 'There will be a
few moments of drug-induced terror, Bill. That is necessary
for the operation. I hope knowing it beforehand will help you
ride with it. It will not be for long.' He squeezed Bill's shoul-
der and was gone.
'The trick was learned early in our history, when this type
of total operation was more often necessary,' the professor
continued. 'It is really quite simple to extinguish one per-
sonality while leaving the other undisturbed. The other per-
sonality in the case before us has been drug-immobilized to
keep this one from shifting. At the last moment, this personal-
ity before us will be drug-stimulated to bring it to the highest
possible pitch of total activity. This produces utterly disor-
ganized activity, every involved neutron and synapse being
activated simultaneously by the drug. It is then a simple
matter for the mnemonic eraser to locate all permanently
echoing frequencies involved in this personality and suck
them into its receiver.'
Bill was suddenly aware that a needle had been thrust
into his arm. Then it was as though all the terror, panic and
traumatic incidents of his whole life leaped into his mind. All
the pleasant experiences and feelings he had ever known
were there, too, but were transformed into terror.
A bell was ringing with regular strokes. Across the panel
of the mnemonic eraser, the tiny counting lights were alive
with movement.
