ALEX COMFORT 
to which I have already referred, and that is now thirty years 
old. And yet I do feel a certain confidence that we are a good 
deal closer than we were to knowing whether we are likely to be 
able to influence human ageing in the near future. We 
are perhaps near enough to spend time occasionally in consid- 
ering the probable consequences if we could do this, because 
we, or our sons, might at the very least prevent some 
foreseeable mistakes and abuses if, for once, we think out the 
possibilities of a new advance in human potentiality before 
it is actually upon us, and before we know whether it is 
practicable. 
One point which is often raised when one speaks of this work, 
and an obvious one in the light of what we have been saying at 
this conference, is the relation of gerontology to the threatening 
growth of world population. If we could lengthen our lives, 
that would clearly have demographic effects which would 
depend on the size of the increase, and, still more from the 
practical point of view, upon which section of the life-cycle 
we are able to prolong. You may recall that Tithonus in 
Greek mythology induced his goddess-wife Aurora to secure 
him immortality from Zeus, but forgot to ask for perpetual 
youth. Cadmus, more wisely, opted to become an animal with 
a long period of adult vigour, and he and his wife were meta- 
morphosed to “two bright and aged snakes that once were 
Cadmus and Harmonia’”’. If we were to produce Tithonuses— 
and that, to some extent, is what medicine is doing by prolong- 
ing life after vigour has declined—we might merit the scepti- 
cism which is sometimes expressed about prolongation of life. 
But that is precisely what gerontology is trying to avoid. If we 
could prolong adult vigour with no increase, or only a small 
increase, in the two phases of dependency—childhood and old 
age—then every day of productive life gained should be a gain 
to humanity. At the moment we may spend from one-third to 
one-half of our potential life in training to become productive, 
whether we are farmers or biologists, and then at the height of 
our experience and performance we are removed by death or 
infirmity. Anything we can do to increase our working life 
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