Arrived at "Grand Central" he kept a sharp lookout for any unusual activity. There was none. All along elevator-row small groups of bookish-looking men returned from their day's work in the Apperception Centers. They looked calm and contented and with their briefcases under their arms almost like ordinary businessmen heading for the commuter train. He didn't dare to linger or to look around. There was this all-pervading sense of being shadowed, of having gone into a trap from which there was no escape, of eyes following him everywhere. Whose eyes? That was impossible to know. Maybe The Brain's; its sensory organs could conceivably be installed anywhere. Maybe that janitor guiding a polishing machine over the rubber floor was a plain clothesman; or maybe it was that detached gentleman who seemed to wait for an elevator with a stack of books under his arms. As the cage shot up to Apperception 27, failure pressed down on his heart. Now it was almost thirty hours since he had released "Ant-termes" into the nerve paths of The Brain. Those undermining and devouring armies; what could have happened to them? Any number of things: Perhaps the Lignin in the nerve paths was poisonous. There had been no time for him to test the stuff. Perhaps the maintenance engineers had replenished the insulation in that sector overnight and all the hives were drowned. Perhaps some kind of a detecting apparatus had found out about the pest inside The Brain right from the start. As long as the beachhead of the underground invasion remained small, its blocking would not impair the functions of The Brain. What a fool he had been to pit dumb little animals against the powers of a God. Oona had been right; he _was_ that knight in rusty armor charging against windmills on a Rozinante.... * * * * * Vivian Leahy dragged him into the reception room of the medical center almost by force. "The doctors have been waiting for you two hours now," she scolded him. "They never did that before for any man. How come you forgot? And you forgot me too; last time you were so nice, I thought you would date me up. I couldn't have resisted your invitation, you know. Now, off with your coat."