DOMESTICATED ANIMALS ,. 39 



More beings are born than can live on the earth. 

 There u an over-production of life. There is not 

 enough food and air and room to go round. It is 

 estimated that a single pair of house-sparrows 

 would, if none should die, produce enough spar- 

 rows to cover the state of Indiana in 20 years. 

 The lobster lays 10,000 eggs in a season, and the 

 oyster 2,000,000. A female white ant, when adult, 

 does nothing but lie in a cell and lay eggs. She 

 lays 80,000 eggs a day for several months. The 

 natural increase of a single pair of gypsy moths 

 would destroy all the plants of the United States 

 in eight years. The eel produces eggs but once in 

 a life-time, but it produces the almost incredible 

 number of from 5 to 20 millions, depending on the 

 size of the fish. Certain low forms of animal life 

 reproduce so rapidly that, if they should all sur- 

 vive, their offspring would in a few days fill the 

 seas. If every egg of the codfish should produce 

 an adult, a single pair in 25 years would produce a 

 mass of fish as large as the earth. 



One result of this overproduction of animal life 

 is a world-wide struggle for existence. The earth 

 is a battlefield. How it may be on other spheres, 

 we do not know. But on the particular globe on 

 which we have been allotted to come into existence 

 life is one mighty tragedy. Species are pushing 

 and crowding and murdering each other in the ef- 

 fort to live. And this pushing and crowding and 

 exterminating has gone on ever since the begin- 

 ning of life on the earth millions of years ago. 



