The Space Bureau authorities were every bit as impressed as we had anticipated. The medics readily found that we had been infested by a germ, but by a benevolent germ, a true symbiote. That discovery was followed by months of tests and examinations. Between sessions with our own medics and laboratory men and various visiting specialists, we amused ourselves by showing our new abilities. At least a dozen times a day I had to put someone down in an arm wrestle. Even when they devised a way to pit two against me at a time, I had little difficulty besting them. Zealley's displays tended toward the more flamboyant. One of the tricks he delighted in was taking a razor blade, and, while his audience watched with repelled fascination, cut a long gash in his forearm. For an instant the blood would ebb out, then quickly clot and cease to flow. The next day he would show them the arm, where a thin red line at the most would remain to mark where the wound had been. Apparently Zealley's reminiscing had kept pace with my own. "It seems such a shame, doesn't it, Max?" he asked. He was genuinely sad. So was I. Test results and theories developed fast in those early days. The findings showed that the symbiotes repaired damage and faults in our systems and protected us against disease. It was even hazarded that they would prolong our lives indefinitely. Yet we were warned against complacency. The bug--we always spoke of it in the singular, even though we knew the original mites had spawned in our blood streams--could not act quickly enough to save our lives in the event of major damage to essential organs or the brain. Also, we could drown. Or we could die in a fall from a great height. Or starve to death. The first intimation we had that all was not well had started as a rumor. Two of the staff biochemists had been experimenting with transplants of the bugs in fruit flies. They had turned up something sensational. Zealley was not present when I received the disastrous news. At the end of what would normally be a twenty- or thirty-year cycle--the chemists were not able to estimate it any closer--the symbiotes evolved into tiny winged insects. At that stage they acquired size and flying strength by devouring the tissues of their hosts. In twenty or thirty years, then, our benign cohabitants would kill us--and spread out by the millions to infest other available animal life. Unless they were destroyed, not only would Zealley and I die, but all humanity on all the worlds would face the prospect of becoming infested. Zealley must have surmised what was coming. He had disappeared a week earlier. Before he left, I had noticed considerable change in our body and facial features. He would very soon be impossible to identify.