DARWIN 117 



were clothed with vegetation, birds flew after insects, 

 and gigantic turtles and lizards lived on the shores. 

 Whence did these plants and animals come ? 

 Darwin examines them. They have an unusual 

 appearance, and seem to point to America. Yet 

 not a single species is now wholly American ; each 

 has its peculiarities. An historical controversy 

 arises over the islands, and men range themselves 

 in parties once more. Empty islands emerge from 

 the blue waters. How are they to be populated ? 

 There are two possibilities. One is that God 

 has created the animals and plants Galapagos 

 animals and plants. But in that case why has he 

 created them entirely on the American model, 

 while diverging from it in small details ? The 

 second possibility is that the animals and plants 

 were brought by the current or the wind from the 

 neighbouring American coast ; they are American 

 plants and animals. After landing on the islands, 

 they adapted themselves to their new surroundings, 

 and were altered. Hence both the resemblance 

 and the difference. The theory assumes, of course, 

 that species are mutable. If that is so, we can 

 explain everything without God. 



But the greatest and tensest struggle began 

 when Darwin returned home. He approached the 

 most audacious, but most striking fact, for his pur- 

 pose. Up to this the question had been whether 

 new species were produced by God or by natural 

 necessity. Now a third element was introduced, 

 man himself. He also alters species, as a breeder 

 of pigeons, rabbits, sheep. He has done it with 



