Heredity 6i 



eliminated and forgiven in the offspring of a natural alli- 

 ance. And even in those less simple cases where an evil is 

 found to be not merely a deficiency but a perversion or 

 misdirection of some positive capacity to evil action, there 

 is usually a cause in a deficiency in the restraining or govern- 

 ing faculties, which makes it amenable to the same law of 

 cumulative replacement. Many failures in physical and 

 mental processes are now attributed to disturbances in the 

 nutrition; to failure of some organ which ought to remove 

 poisonous waste products, which omission allows toxic 

 substances to affect the nerves or brain or will, much as 

 drugs will affect them. It is easy to see how a defective 

 organ of elimination may be remedied by the addition of a 

 healthy heredity and so seem to overcome a positive evil. 

 Even when the evil capacity is positively transmitted it is 

 found under Mendel's law of heredity to pass to only a 

 limited number of offspring and so to be in course of extinc- 

 tion by natural selection. And it must be remembered that 

 many qualities called evil are merely conventionally and 

 temporarily evil because of man's present customs. Exces- 

 sive meekness or excessive courage might well be virtues 

 under other circumstances. Such qualities may recur in- 

 opportunely in heredity under laws of reversion and varia- 

 tion. Nature is always experimenting under changes of 

 environment, and when changes of environment are frequent 

 and abrupt, nature is called upon for sudden adaptation. 

 Then many reversions are produced. Instincts long dormant 

 may be awakened by the removal of a restraining instinct 

 more recent. Even such an emotion as blinding anger 

 may reappear as a virtue; and may suddenly again meet 



