Berti smiled. “Human intelligence never had the slightest possibility of survival. Its high cerebral specialization never had any physiological unity with the primitive muscles and nervous system. A slight chemical disturbance of the blood and the human went mad. Take away a little oxygen—his great mind was gone. Decrease the blood’s calcium—convulsions, coma, death. Slight reduction in sugar—and his mighty cerebrum blotted out, died. A slight environmental change could destroy man—aside from his obvious willingness to destroy himself. But, Rolly, in one way, perhaps, extinction, the price of evolution, isn’t too high. After all, you made us possible.”
Roland heard himself say, weakly, “But they still live out there—humans—surely they’re not—”
“But we rule,” said the woman coldly. “They—what will they do? That will be interesting. Anyway, it’s their twilight, like apes and saurians. Our dawning.”
“You’re almost gone, Rolly, dwindling away like a stream,” said Berti. “World Brain was proof against any organic enemy, including us. But not against you. A matter of kind against kind. Remember De Morgan’s familiar lines? But then you wouldn’t, would you? ‘Great fleas have little fleas upon their backs to bite ’em; and little fleas have lesser fleas, and so on, ad infinitum; and the great fleas themselves in turn have greater fleas to grow on, while these again have greater still, and greater still, and so on.’ We used you, Rolly. A machine to bite a machine. That was the only way it could have been done.”
Very far away, dim and wavering, Roland heard the woman saying, “Logically, any species has some overly-specialized characteristic that might defeat it. I wonder what particular little flea will bite us?”
“And that, too, will be interesting,” thought Roland grimly, as his electronic brain thinned into meaningless chaos, and he returned into the hazes of unconsciousness from which he had emerged three hours before.