6 Heredity and Eugenics 



4. More intimate knowledge of the structure of plant 

 and animal bodies revealed what were called "rudimentary" 

 structures, which are quite evidently abandoned structures. 

 This suggested at once that they were functioning structures 

 in the ancestral forms. Even man, and perhaps man most 

 of all, was recognized as being a walking museum of antiquity. 



5. Then the life panorama of the geological record 

 began to be unrolled ; and it became clear that a fauna and 

 a flora totally unlike that of today existed in the earliest 

 periods; that as one approached the later records, resem- 

 blances began to appear; and that insensibly the fauna 

 and flora of the ancient world merged into those of today. 

 This was historical evidence of tremendous weight in favor 

 of the fact of a gradual organic evolution. 



6. Soon what is called embryology began to be studied, 

 and plants and animals were traced, stage by stage, from 

 the egg to the adult form. In the course of this develop- 

 ment resemblances to other forms appeared, which had 

 disappeared when the adult stage was reached. And so 

 the idea developed that here were glimpses of earlier con- 

 nections, and it became formulated in the well-worn state- 

 ment that the history of the individual repeats the history 

 of the race, a theory labeled "recapitulation." 



7. Men's eyes also began to be opened to the fact that 

 great changes had been wrought in plants by cultivation, 

 and in animals by domestication ; so great in many cases that 

 the wild originals could not be recognized mth certainty. 

 Later, Darwin called this "an experiment upon a gigantic 

 scale, " but it was an experiment unconsciously performed. 

 At least it proved that the operations of man could modify 

 plants and animals, and modify them so much that resem- 

 blances to the wild originals would be obscured. 



