Attempts have been made to find some explanation of the mental and moral inequalities that exist at birth. In the earlier days of the study of evolution it was usually asserted that the human being inherits his mentality and morality from his parents. But even if that were true the injustice of one being born a genius and another a fool would remain. It is the fact of inequality that constitutes the injustice, and it is of no importance whether it comes about through heredity or otherwise. But as a matter of fact heredity is confined to the physical side of existence. As more and more is learned by observation the old theory of mental and moral heredity has lost ground until it can be said that it now has no recognition in the scientific world. Nobody is better qualified to speak upon the subject than those with practical experience. Dr. A. Ritter, of the Stanford University Children's Clinic, that has large numbers of defective children in charge, treating no less than sixteen hundred in a single year, says: "As to the definite causes of the prevalence of defective types, I cannot speak with finality or assurance. I do not agree with social or educational doctrinaires who assign the causes definitely to liquor, poverty, infectious diseases, or other social or moral shortcomings. The greatest minds of the world are hesitant in theorizing about this. There are a complex of causes which explain many of these cases, but no generalization fits absolutely. We may find a case which is not traceable to any of these conditions--_a case in which the antecedents would promise a perfectly normal child, and yet we are confronted with a defective child_. On the other hand, bright, normal children, even children of superior intelligence sometimes spring from such conditions."[L] A little reasoning about the facts concerning both genius and idiocy will make it clear that neither is inherited. If it were true that genius is inherited society would present a different appearance. There would be famous families of geniuses living in the world, in music, in poetry, in warfare, in invention, in art, if genius were inherited. The fact is that it is difficult to find even two geniuses in any family. The Caesars, Napoleons, Edisons, Lincolns, Wagners, Shakespeares, stand alone with neither great ancestors nor great descendants. We search in vain for great ancestors for such men; but if the theory of mental heredity were sound we should know their ancestors for precisely the same reason that we know them.