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 



