"They are too impotent to represent any hazard to his present body mechanism," Toolls replied. "If and when he dies, it will not be from disease." "He will be subject to the deterioration of old age, the same as we are, won't he?" Macker asked. "Of course," Toolls said, "but that's the only thing that will be able to bring him down. He cannot be harmed by any force this 'light' world can produce; he is impervious to sickness; and he will live indefinitely." "Indefinitely?" "As his world reckons time. Their normal life span is less than a hundred years. Ours is over five thousand. He will probably live approximately twice that long, because he will be subjected to less stress and strain, living as he does on a world of lighter elements." "Then we have truly made a superman," Macker's tones inflected satisfaction. "I wish we were returning this way in a thousand years or so. I'd like to see the monumental changes he will effect." "We may at that," Remm said, "or others of our people will. He will probably be a living legend by then. I'd like to hear what his race has to say about him. Do they have names with which to differentiate individuals?" "Yes," Toolls said. "This one has a family designation of Pollnow, and a member designation of Orville." "It will be necessary for us to leave in exactly ten minutes," Remm reminded them. "Our next stopping place--the red star--will reach its nearest conjunction with this planet by the time we meet it out in space." "Then we will have time to do nothing more for him before we go," Macker said. "But as far as I can see we've forgotten nothing, have we, Toolls?" "Nothing," Toolls answered. "No--we forgot nothing." * * * * * But Toolls was wrong. They had forgotten one thing. A minor detail, relatively.... On Toolls' world his race, in the course of its evolution, had adjusted itself to its own particular environment. Logically, the final result was that they evolved into beings best able to survive in that environment. As such their food--a "heavy," highly concentrated food--was ideally suited to supply the needs of their "heavy," tremendously avid organisms. Orville Pollnow had no such food available. His body--no larger than before--had an Earth mass of one hundred and eighty thousand pounds. One hundred and eighty thousand pounds--the weight of twelve hundred average sized men--of fiercely burning, intense virility. Even continuous eating--of his own world's food--could not supply the demands of that body. Twenty-four hours after the aliens left, Pollnow was dead--of starvation. THE END Transcriber's Note: This etext was produced from _If Worlds of Science Fiction_ July 1952. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed. Minor spelling and typographical errors have been corrected without note. End of the Project Gutenberg EBook of Vital Ingredient, by Charles V. De Vet