MENTAL AND SOCIAL EVOLUTION 147 



was the real head of the gens or kin. The evolution 

 of society, at every step, was not controlled by senti- 

 ment, or idealism, or by a priori reasoning, but by 

 purely materialistic conditions; or, in other words, by 

 economics; and this was always determined solely by 

 the principle of natural selection, the adaptation of the 

 fittest to the physical welfare of the social unit. 



Captain Fitz-Roy, of the good ship Beagle, carrying 

 Professor Darwin round the world, brought also from 

 England, a young Fuegian, who had been taken to that 

 country two years before. This boy was returning to 

 his people in the territory adjoining Magellan's Straits, 

 at the south end of South America. He was dressed 

 in civilized costume, could talk broken English, and 

 took with him several articles of English manufacture. 

 He was left on shore, as the vessel passed through 

 the Straits toward the Pacific Ocean. When the ship 

 returned some months, or years later, the Captain 

 landed and hunted up the boy. The first day. he did 

 not find him. But the next morning, "a canoe," says 

 Darwin, "with a little flag flying, was seen approaching, 

 with one of the men in it, washing the paint off his face. 

 This man was poor Jemmy, now a thin, haggard 

 savage with long, disordered hair, and naked, except a 

 bit of blanket round his waist. * ' * * We had left 

 him plump, fat, clean, and well-dressed: I never saw 

 so complete and grieveous a change. " (It was grieveous 

 to Darwin, but not to Jemmy). * * * "He told us 

 he had enough to eat, that he was not cold, that his 

 relatives were very good people, and that he did not 

 wish to go back to England." Darwin goes on to say, 

 "I do not doubt now, that he will be as happy as, 

 perhaps happier than, if he had never left his own 

 country. Everyone must sincerely hope that Captain 



