THE PURPOSIVE IMPROVEMENT OF THE HUMAN RACE 573 



white rats through twelve to seventeen generations. He is 

 convinced that there is some evidence that such training 

 does shghtly affect heredity, but such modification is so 

 shght and slow that he honestly admits the improbabihty 

 of greatly improving the human race by the inherited effects 

 of good environment, good training or good education. 

 Other investigators, notably Bagg (1920) and MacDowell 

 (1924) have found no evidence that the training of ancestors 

 facihtates the learning of the descendants in the case of 

 mice and rats. 



Of course good environment, training and education 

 greatly improve individual development but in spite of the 

 fact that no one has ever proved conclusively that they 

 improve heredity or that the effects of use or disuse are 

 inherited, this doctrine of "the inheritance of acquired 

 characters" is still maintained by many persons who feel 

 that it ought to be true even if it is not, and who sometimes, 

 by hook or crook, attempt to make nature agree with their 

 theories. So many persons have gone wrong morally in 

 maintaining that acquirements are inherited, from the 

 patriarch Jacob in his deahngs with his father-in-law Laban 

 down to a few real scientists and many pseudo-scientists of 

 the present day, that an interesting article might be written 

 on "The influence on moral character of the doctrine of the 

 inheritance of acquired characters." If the inheritance of 

 acquired characters were as important a factor in human 

 progress as some persons suppose, it would not be necessary 

 to make a minute search for it in every hole and corner, it 

 would occur frequently and indubitably, but even its defend- 

 ers must admit that it occurs rarely and doubtfully if at all. 

 All human experience teaches that children still have to learn 

 their mother tongue, that they still have to be "house- 

 broken," that they still have to be taught good habits, that 

 they still must be taught what is right and what is wrong, 

 although such training has been going on for countless 

 generations. In these and in a thousand other instances the 

 universal experience of mankind confirms the conclusions of 

 the biologists that the effects of training are not inherited. 



But while the acquirements and experiences of former 

 generations are not passed on to descendants through the 



