REJUVENESCENCE 157 
man and the higher animals than is now possible, 
but when we remember that the present condition 
of the protoplasmic substratum of these organisms 
is the result of millions of years of evolutionary 
equilibration, we cannot but admit that this task 
may prove to be one of considerable difficulty.” 
We should just think it will, but we are slow to 
conclude that we must simply say as of old: “ And 
so from hour to hour, we ripe and ripe; and then, 
from hour to hour, we rot and rot.” For in the 
biological facts we find more than a hint that 
changes are lightsome; that habituations age us; 
that new work, new scenes, new play, new rest, at 
the worst new diet, should be experimented with; 
that we should cultivate in our pilgrimage the ad- 
venturous mood, for if it be true that a man is just 
as old as his arteries, it is also true that he is as 
young as his mind is. Our life is, we suspect, largely 
punctuated beforehand, but certainly not wholly. 
We can put in commas, and we have a sporting 
chance of inserting semicolons. In any case, our 
effort to stave off senescence is likely to be rewarded 
by an evasion of senility. 
