128 SECRETS OF ANIMAL LIFE 
which were here a few months ago are asleep, or 
have gone on a journey, or have, as individuals, 
ceased to be. 
The wintry aspect of the realm of organisms must 
be considered from within and from without, for 
life is rhythmic and is punctuated by the seasons. 
On the one hand, there is a deep reason why high- 
level activity cannot be for long continuous, why 
it must be interrupted by periods of rest. It is 
not merely that the living engine has to be stoked; 
it is that the framework requires opportunity to 
keep passably young. It is continuity that kills, 
For many creatures winter is the time when processes 
of rejuvenescence get a chance to counteract the 
encroachments of senescence. How useful, often, 
for the overworked brain is it to sleep the round of 
the clock. The hibernal slumbers of hedgehog and 
dormouse, of marmot and bat, the winter coma of 
tortoise and slow-worm, the lethargic condition of 
frogs and snails, are no doubt adaptive reactions to 
severe external conditions, subtle organic illustra- 
tions of Brer Rabbit’s policy of “lying low and 
saying nuffin”; but our point is that the quiescence 
of winter has in some cases a more internal aspect, 
it is the inevitable pause in a strenuous life. Quite 
extraordinary in some humble, but intensely active, 
animals (Bryozoa, for instance) is the way in which 
the framework can be periodically taken to pieces 
and built up again. One suspects that organic 
immortality is commoner than is usually supposed. 
And the recuperation has obviously a prospective 
