We've increased our temporal range to the point where it's not at all unusual to meet active and alert people who've passed the century mark. Society has done that by a system of care which is pre-prenatal, by seeing to it that every human being grows up in the best possible environment and receives the best possible nutrition, and by prophylactic measures of all possible sorts. In a word, we've eliminated from human life all the stresses and strains which can be eliminated. And that's the nearest to immortality we'll ever get.