Doctor Hélius was the genius chimpanzee director of the Research Institute's Encephalic research studies, in the Pierre Boulle novel La Planète des singes. He performed experimental operations on the brains of human captives. A friend of Cornélius, he agreed to demonstrate some of his findings to the human astronaut Ulysse Mérou.
The chimpanzee proudly demonstrated various experiments conducted in his department. He was oblivious to Ulysse's disgust and horror at the callous treatment of the men and woman in which these experiments were conducted. Ulysse's temper finally reached its limit when he witnessed a lovely young girl, that reminded him of his wife, Nova, be subjected to a continuous electrical current which caused the entire left side of her body to convulse violently. After demanding them to stop Cornelius calmed stating such experiment were necessary escorted the human to the next room.
In one experiment he displayed a man who was able to talk like a gramophone, repeating words and conversations he had heard in captivity. However his second subject, a woman, revealed some of his most profound discoveries in awakening the memory of the species.
These remarkable experiments revealed memories inherited by the human subjects from their distant ancestors, and proved that the humans of the planet Soror had not only been intelligent, but had once been the dominant species of the planet.
Shortly after the presentation, the chimpanzee had leaked out his findings to the public causing a media panic that the Institute had finally made man able to talk. Hélius's revelation as man being the former masters of Soror may have accelerated the Grand Council of Soror in singling out Ulysse and his family as threats.