THE LIFE CYCLE 103 
large animals are long-lived and small animals have short 
lives. 
61. Death— At the end comes death. After the animal 
has completed its life cycle, after it has done its share toward 
insuring the perpetuation of its species, it dies. It may 
meet a violent death, may be killed by accident or by ene- 
mies, before the life cycle is completed. And this is the 
fate of the vast majority of animals which are born or 
hatched. Or death may come before the time for birth or 
hatching. Of the millions of eggs laid by a fish, each egg 
a new fish in simplest stage of development, how many or 
rather how few come to maturity, how few complete the 
cycle of life! 
Of death we know the essential meaning. Life ceases 
and can never be renewed in the body of the dead animal, 
It is important that we include the words “can never be 
renewed,” for to say simply that “life ceases,” that is, that 
the performance of the life processes or functions ceases, 
is not really death. It is easy to distinguish in most cases 
between life and death, between a live animal and a dead 
one, yet there are cases of apparent death or a semblance of 
death which are very puzzling. The test of life is usually 
taken to be the performance of life functions, the assimila- 
tion of food and excretion of waste, the breathing in of oxy- 
gen, and breathing out of carbonic-acid gas, movement, 
feeling, etc. But some animals can actually suspend all 
of these functions, or at least reduce them to such a mini- 
mum that they can not be perceived by the strictest exami- 
nation, and yet not be dead. That is, they can renew 
again the performance of the life processes. Bears and 
some other animals, among them many insects, spend the 
winter in a state of death-like sleep. Perhaps it is but sleep; 
and yet hibernating insects can be frozen solid and remain 
frozen for weeks and months, and still retain the power of 
actively living again in the following spring. Even more 
remarkable is the case of certain minute animals called Ro- 
