The Caves of Mars

Ric Coltor had lost an arm in an interplanetary exploration. For a spaceman at any other time, that would have meant the end of his career. But not with the marvelous Martian Panacea in existence. Extracted from a fungus found only on the Red Planet, it promised mankind perfect health and longer life, for it grew back internal organs, conquered disease, and could even grow back arms.

So Ric went to one of the M-P colonies to become whole again and discovered a defect in that new Utopia - M-P not only gave its users glowing good health, but it also gave them a fanatical devotion to the man who administered it, Dr. Morton Krill. A devotion that was so all-encompassing that any man who received it could easily become dictator of two planets if he were twisted enough to desire that. Dr. Krill was.