INTRODUCTION 7 



eludes everything that goes to make up civilization, 

 such as the arts, sciences, literature and traditions. 

 With this kind of heredity we are not here concerned, 

 for this is not what is meant by biological heredity. 



Professor Castle, in his book on "Heredity in Rela- 

 tion to Evolution and Animal Breeding," has defined 

 heredity as "organic resemblance based on descent." ' 

 The son resembles his father because he is a "chip off 

 the old block." It would be still nearer the truth to say 

 that the son resembles his father because they are 

 both chips from the same block, since the actual char- 

 acters of parents are never transmitted to their off- 

 spring in the same way that real estate or personal 

 property is passed on from one generation to another. 

 When the son is said to have his father's hair and his 

 mother's complexion it does not mean that paternal 

 baldness and a vanishing maternal complexion are 

 the inevitable consequences. 



Biological inheritance is more comparable to the 

 handing down from father to son of some valuable 

 patent right or manufacturing plant by means of 

 which the son, in due course of time, may develop an 

 independent fortune of his own, resembling in char- 

 acter and extent the parental fortune similarly de- 

 rived although not identical with it. 



So it comes about that "organic resemblance" be- 

 tween father and son, as well as that which often 

 appears between nephew and uncle or even more re- 

 mote relatives, is due not to a direct entail of the 

 characteristics in question, but to the fact that the 

 characteristics are "based on descent" from a common 



