176 SECRETS OF ANIMAL LIFE 
by those species of “ water-bears ” that live in moss, 
by many wheel-animalcules or rotifers, by some of 
the minute Crustaceans known as water-fleas, and 
by some still simpler animals. In some cases what 
endures is the whole creature as such; in other 
cases it may be a cyst formed inside the animal, 
or, it may be, just an egg with a resistant shell. 
From dried mud taken from a pond and kept in a 
box for ten years, one can by putting a sample into 
water rear many little creatures. Professor Giard 
found that the eggs of the large freshwater 
Crustacean called Apus could survive twelve years 
of drought. Some Protozoa dried on paper were 
revived after five years. It is difficult, no doubt, 
to draw a strict line between these cases of latent 
life and other conditions of lying low, as in the true 
winter-sleep or hibernation of hedgehog and dor- 
mouse, or the winter-torpor of the frogs in the mud 
of the pond and the snails in the recesses of the old 
wall, or the lethargy of some fishes that encapsule 
themselves in the mud during the dry season and 
suddenly reappear when the rains return; but 
what marks off latent life in the stricter sense is 
the desiccation of the organism and the entire 
absence of any positive signs of “life.” The ques- 
tion is whether the activities which we sum up in the 
word “life” have come to a standstill, or whether 
the fire is still burning, but very low? We cannot 
dissociate activity from our idea of life, but here is 
an organization so dry that it is brittle, in which 
we can detect no movements, not even chemical 
