58 THE NEXT GENERATION 



immigrants and emigrants alike would be able to walk across 

 a slippery cod pathway between Europe and America. 



Dr. Thompson also says that " if all the progeny of one 

 oyster survived and multiplied, its great-great-grandchildren 

 would number sixty-six with thirty-three noughts after it 

 (66,000,000,000,000,000,000,000,000,000,000,000), and the 

 heap of shells would be eight times the size of the world." 



No human mind can grasp such figures as these. They 

 are indeed extreme examples of the first law of Darwin's 

 famous five-linked chain. 



II. The Struggle for Existence 



.The second law follows as a matter of course. Indeed, 

 there is no escaping it, for with creatures of every kind 

 multiplying at this rate, — with each of them obliged to 

 find food or die, — the competition grows terrific. It becomes 

 a struggle merely to keep alive. This, then, is the second 

 link of Darwin's chain. 



It seems a peaceful world as I glance out of my window 

 at the present moment. But, without seeing it done, I know 

 that all forms of life are struggling not merely for food but 

 for very existence too. Large insects are living on those that 

 are smaller ; small birds are living on large insects ; birds are 

 killing worms ; cats are killing birds ; dogs are killing rabbits ; 

 man is killing and eating birds and beasts of many different 

 kinds ; microbes are killing millions of creatures both large 

 and small ; and man is killing microbes. 



The slaughter is universal ; the conflict is colossal. It con- 

 tinues on every side every day, and it is inevitable. For if the 

 supply of plants and animals were not limited in some way, 

 — if all eggs were allowed to hatch and if all young animals 

 lived on to good old age, — there would soon be such a battle 



