"The objective in a total operation of the sort before us is to distinguish all the stored permanent frequencies, typical of the personality you wish to extinguish, from the frequencies 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 shoulder 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 personality while leaving the other undisturbed. The other personality in the case before us has been drug-immobilized to keep this one from shifting. At the last moment, this personality before us will be drug-stimulated to bring it to the highest possible pitch of total activity. This produces utterly disorganized activity, every involved neuron 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. There was in Bill a fright, a demand for survival so great that it could not be felt. It was actually from an island of complete calm that part of him saw the medical students rising dismayed and white-faced from their seats. It was apart from himself that his body strained to lift some mountain and filled the operating amphitheater with shrieking echoes. And all the time the thousand eyes of the mnemonic eraser flickered in swift patterns, a silent measure of the cells and circuits of his mind. Abruptly the tiny red counting lights went off, a red beam glowed with a burr of warning. Someone said, "Now!" The mind of Bill Walden flashed along a wire as electrical energy and, converted on the control panel into mechanical energy, it spun a small ratchet counter. "Please sit down," the professor said to the shaken students. "The drug that has kept the other personality immobilized is being counteracted by this next injection. Now that the sickly personality has been dissipated, the healthy one can be brought back rapidly.