Longevity of Man and his Tissues 
we make. If we lost it, it would alter both us and our culture. 
It would be typical of the trend of science generally if we did 
bring this about, for science characteristically reduces the num- 
ber of physical necessities and emotional certainties, thereby 
increasing the range of human choice. Whether it can do this 
to the lifespan, by freeing us from the necessity of becoming 
infirm and dying at the fixed ages we now must, remains to be 
seen. 
229 
