REVERSION. 45 



means those in most perfect harmony with the en- 

 vironment. And as the creature cannot survive long 

 in an environment to which he is not suited, there- 

 fore the offspring of the extreme variation from the 

 normal must of necessity return to the original family 

 type, or cease to exist because of its unfitness. 



When these extreme variations appear, as they do 

 in a wholly unaccountable manner from time to time, 

 this law of reversion comes into action and is not in- 

 frequently successful in bringing back the wanderer; 

 but should it fail in doing so the extreme variety 

 cannot be continued, either there will be no offspring, 

 or if there be it will prove sterile. Thus the continu- 

 ance of the grossly unfit becomes impossible. When 

 variation is extreme, reversion or extinction must 

 take place, and whether reversion or extinction is to 

 be the verdict of Nature, depends to a great extent 

 upon the conduct of the individual representing the 

 variety. If he or she join with another of the same 

 variety for the continuance of the race, there will 

 probably be no offspring, or if there be it will prove 

 sterile = extinction ; while if he or she join with a 

 normal fellow, or one belonging to a different variety, 

 Nature will seize upon the opportunity offered by 

 the infusion of fresh blood, and in the offspring 

 " throw back " to the old family type = reversion. 

 And this law is equally active whether the variation be 

 physiological or pathological. It is impossible to con- 

 tinue a family all idiots, or dwarfs, as it is impossible 

 to continue one all giants, or geniuses. The individual 



