Johnny smiled tiredly and rested his head on one hand. "He had to remake me chemically, you know. How could I spread change without being changed myself? I couldn't have two generations to adapt to it naturally like you, Ric. It had to be done artificially. It took years. You understand? I'm a community, a construction. The cells that carry on the silicon metabolism in me are not human. Dad adapted them for the purpose. I helped, but I can't remember any longer how it was done. I think when I've been badly damaged, organization scatters to the separate cells in my body. They can survive better that way, and they have powers of regrouping and healing. But memory can't be pasted together again or regrown." John Drake rose and looked around the laboratory with something like triumph. "They're too late. I made it, Ric. There's the catalyst cooling over there. This is the last step. I don't think I'll survive this plague, but I'll last long enough to set it going for the finish. The police won't stop me until it's too late." * * * * * Another plague! The last one had been before Alcala was born. He had not thought that Johnny would start another. It was a shock. Alcala walked over to the cage where he kept his white mice and looked in, trying to sort out his feelings. The white mice looked back with beady bright eyes, caged, not knowing they were waiting to be experimented upon. A timer clicked and John Delgados-Drake became all rapid efficient activity, moving from valve to valve. It lasted a half minute or less, then Drake had finished stripping off the lab whites to his street clothes. He picked up the square metal box containing the stuff he had made, tucked it under his arm and held out a solid hand again to Alcala. "Good-by, Ric. Wish me luck. Close up the lab for me, will you?" Alcala took the hand numbly and mumbled something, turned back to the cages and stared blindly at the mice. Drake's brisk footsteps clattered down the stairs. * * * * * Another step forward for the human race. God knew what wonders for the race were in that box. Perhaps something for nerve construction, something for the mind--the last and most important step. He should have asked. There came at last a pressure that was a thought emerging from the depth of intuition. _Doctor Ricardo Alcala will die in the next plague, he and his ill wife Nita and his ill little girl.... And the name of Alcala will die forever as a weak strain blotted from the bloodstream of the race...._ He'd find out what was in the box by dying of it! He tried to reason it out, but only could remember that Nita, already sickly, would have no chance. And Alcala's family genes, in attempting to adapt to the previous steps, had become almost sterile. It had been difficult having children. The next step would mean complete sterility. The name of Alcala would die. The future might be wonderful, but it would not be _his_ future!