It was called, for the press and public, just “adaptene," but only the most trusted officials of the Institute knew what it was by formula. By its very nature, it had to be shrouded in secrecy and kept from the hands of unscrupulous individuals. The Earth Union Government controlled exclusively the manufacture and use of adaptene.

Adaptene was the parent substance of all hormones in the living body. It controlled all metabolism, and therefore all the body processes to the last one.

Most remarkable of the applications of this near-miraculous substance had been the conquest of Jupiter’s inimical environment. It had seemed impossible at first. At Jupiter's surface was a crushing gravity, almost three times that of Earth, that made human bones and muscles crack in a few hours.

A moisture-choked heat, from the Titanic layers of pressing gases, promised constantly parched throats and slowly boiling skin. Worst of all, the atmosphere itself was laden with gases, besides oxygen, never meant for earthly lungs — methane, ammonia, and even traces of searing bromine that exuded from volcanic sources and gave the whole atmosphere its brownish tinge.

The natural life-forms of Jupiter's wild environment were adapted by millions of years of evolution. How could Earthmen, nurtured ia a gentler climate, meet that terrible challenge?