HUMAN AND ANIMAL EVOLUTION CONTRASTED 11 



modern study of heredity has disclosed the fact 

 that there is a noticeable permanency in the nature 

 of inherited traits. It has shown how definite char- 

 acteristics are handed on from parent to child gen- 

 eration after generation, showing in each successive 

 generation the same characters as at the start. It 

 has told us that such traits may seem to disappear en- 

 tirely in one or more generations to reappear later 

 unchanged in some subsequent generation. 3. 

 Modern study has even shown something of the laws 

 by which different characteristics, dominant or re- 

 cessive, as we call them, are transmitted to posterity, 

 and has particularly emphasized the idea that such 

 characteristics, in some cases, remain as distinct as 

 at the start in spite of crossbreeding. Inheritance 

 has been thus shown to be a very definite thing, far 

 more fixed in the race than we formerly believed. 

 We have learned that desirable traits cannot be 

 brought into inheritance or forced out by any kind 

 of training, for inherited traits are fixed. All 

 this emphasizes the fact that to produce a good race 

 of offs})riug "nature, and not nurture/' must be 

 appealed to as the dominant force. 



In all this, again, we find that it is assumed that 

 the laws that control animal inheritance apply 

 equally to man ; and again we say that this is doubt- 

 less true up to a certain point. Doubtless the human 

 animal was the result of the same kind of laws of 

 reproduction and heredity that have guided the evo- 

 lution of the animal kingdom. Out of this concep- 

 tion has emerged the interest that has appeared in 

 the modern study of eugenics. A couple of genera- 

 tions ago it was possible to teach that a child's edu- 

 cation should begin "a hundred years before he is 



