36 THE PHYSICAL KINSHIP 



not increase from one year to another. The 

 elephant is the slowest breeder of all animals, yet, 

 if they should all live, the offspring of a single 

 pair in 750 years would, according to Darwin, 

 number nearly 19,000,000. It has been shown 

 that at the normal rate of increase of English 

 sparrows, if none were to die save of old age, it 

 would take but twenty years for a single pair to 

 give one sparrow to every square inch in the State 

 of Indiana (7). A single cyclops (one of the 

 humbler crustaceans) may have 5,000,000 descen- 

 dants in a season. One aphis will produce 100 

 young, and these young will reproduce in like 

 manner for ten generations in a season, when, if 

 they should all live, there would be a quintillion 

 of young. A female white ant, when adult, does 

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

 80,000 eggs a day regularly for several months. 

 An oyster lays 2,000,000 eggs in a season, and if 

 all these eggs came to maturity a few dozen 

 oysters might supply the markets of the world. 

 The tapeworm is said to produce the incredible 

 number of 1,000,000,000 ova, and some of the 

 humbler plants three times this number of spores. 

 If each egg of the codfish should produce an adult, 

 a single pair in twenty-five years would produce a 

 mass of fish larger than the earth. Lower forms 

 of life are even more prolific than the higher. 

 Maupas said that certain microscopic infusorians 

 which he studied multiplied so rapidly that, if 

 they should continue to multiply for thirty-eight 

 days, and all of them should live, any one of them 



