MEDICAL ADVANCEMENT AS PRECLUDING HUMAN EVOLUTION 227 



To show that natural selection operates in the direction of mental as 

 well as physical qualities it is but necessary to cite a few illustrations. 

 When America was discovered the wild animals were generally tamer 

 than now. This tameness however varied, and when the white man 

 began to hunt them down, those that were tamest and most easily 

 approached were killed and consequently had no offspring. Those 

 that were wary and kept out of sight or range of man, escaped and 

 became the parents of the subsequent stocks which varied around the 

 parents with reference to this mental quality — wildness or wariness. 

 And so by a continuous process of maintaining the wilder ones the type 

 of offspring deviated from the average of the parents for this quality 

 and animals become wilder and wilder. In breeding turkeys the farmer 

 obviously keeps those for the stock that stay about the farmyard, while 

 those that stray he sells. 



Romanes 1 in describing a visit to the Falkland Islands and the Land 

 of Terre del Fuego gives some interesting light along this line. In the 

 former, the large land birds were so tame that they could easily be 

 approached by man. A hawk, usually so wary, could not be urged to 

 move from a lower limb until pushed off with the muzzle of a gun. In 

 the Land of Terre del Fuego the same animals were much wilder because 

 harassed for four centuries by man all tame ones were killed by him 

 and the wild remained to perpetuate the type. In the Falkland Islands 

 the alligator was so tame that he could be pulled about by the tail without 

 at all frightening him. But when pushed into the sea he immediately 

 struggled to get out, because selection for long centuries had taken place 

 with reference to sharks. Those alligators that were not wary were 

 devoured and their type became extinct. The goose of certain Pacific 

 islands is not afraid of man who is a recent comer but is very careful of 

 the fox who is an old persecutor. Birds that have instincts which cause 

 them to fly south during winter have greater chances to survive and 

 perpetuate their type, than those that remain behind and are probably 

 starved or frozen. 



Consciousness and intelligence are late acquirements of living crea- 

 tures, and selection before their acquisition must have been mainly with 



1 Mental Evolution in Man, appendix. 



