''That's because we don't allow them to be like that. We preserve them from diseases. We keep their internal secretions artificially balanced at youthful equilibrium. We don't permit their magnesium-calcium ratio to fall below what it was at thirty. We give them transfusion of young blood. We keep their metabolism permanently stimulated. So, of course, they don't look like that. Partly, ''he added, ''because most of them die long before they reach this old creature's age. Youth almost unimpaired till sixty, and then, crack! the end.''