“Now they are all reduced to virtual slavery. An army of spies watches over them, and an army of warriors keeps them from turning against their masters; they are miserable, helpless, and hopeless. “Those of us who escaped with our jong sought out this distant, uninhabited island. Here we constructed tree cities, such as this, far above the ground, from which they cannot be seen. We brought our culture with us and little else; but our wants are few, and we are happy. We would not return to the old system if we might. We have learned our lesson, that a people divided amongst themselves cannot be happy. Where there are even slight class distinctions there are envy and jealousy. Here there are none; we are all of the same class. We have no servants; whatever there is to do we do better than servants ever did it. Even those who serve the jong are not servants in the sense that they are menials, for their positions are considered posts of honor, and the greatest among us take turns in filling them.” “But I still do not understand why you choose to live in trees, far above the ground,” I said. “For years the Thorists hunted us down to kill us,” he explained, “and we were forced to live in hidden, inaccessible places; this type of city was the solution of our problem. The Thorists still hunt us; and there are still occasional raids, but now they are for a very different purpose. Instead of wishing to kill us, they now wish to capture as many of us as they can. “Having killed or driven away the brains of the nation, their civilization has deteriorated, disease is making frightful inroads upon them which they are unable to check, old age has reappeared and is taking its toll; so they seek to capture the brains and the skill and the knowledge which they have been unable to produce and which we alone possess.” “Old age is reappearing! What do you mean?” I asked. “Have you not noticed that there are no signs of old age among us?” he inquired. “Yes, of course,” I replied, “nor any children. I have often meant to ask you for an explanation.” “These are not natural phenomena,” he assured me; “they are the crowning achievements of medical science. A thousand years ago the serum of longevity was perfected. It is injected every two years and not only provides immunity from all diseases but insures the complete restoration of all wasted tissue. “But even in good there is evil. As none grew old and none died, except those who met with violent death, we were faced with the grave dangers of overpopulation. To combat this, birth control became obligatory. Children are permitted now only in sufficient numbers to replace actual losses in population. If a member of a house is killed, a woman of that house is permitted to bear a child, if she can; but after generations of childlessness there is a constantly decreasing number of women who are capable of bearing children. This situation we have met by anticipating it.