THE DESCENT OF BAD TEAITS AND GOOD. 267 



marrying has done for nations standing nearly on 

 a level with each other. But the inferior race is 

 not lifted as much as the higher is lowered, when 

 the difference in the level of the two is great origi- 

 nally. 



11. There has hardly been produced in history a 

 great nation, or a great man, not composed of very 

 diverse inherited complementary elements; but the 

 intermingling has usually been of strong bloods. 



12. The application of the laws of hereditary de- 

 scent to human improvement is, therefore, beset with 

 great natural difficulties, and will continue to be so, 

 until, by other means than the laws of heredity, the 

 intellectual, and especially the moral, averages of 

 merit in the human family shall be greatly height- 

 ened. 



Dana in his Geology raises the question whether a 

 being better than man is to succeed the human race 

 on this planet. {The Geological Story briefly told, pp. 

 253-255.) Superior to any form of life now on the 

 globe, what will be that future creature, as much 

 better than man as he is better than the brutes which 

 he follows in the line of development ? We know, as 

 Agassiz has taught us, that the fish and the serpent 

 have horizontal spinal columns, but that the highest 

 animal organisms below our own have spinal columns 

 in oblique position, and that at last man has attained 

 the erect attitude, and so has fulfilled the possibilities 

 of his anatomical structure. But there are those 

 who Bay, that, just as in past geological ages there 

 were premonitions of better things to come, so in this 



