Adolescence is a new birth, for the higher and more completely human traits are now born.
~ G. Stanley Hall
Civilization is so hard on the body that some have called it a disease, despite the arts that keep puny bodies alive to a greater average age, and our greater protection from contagious and germ diseases.
The man of the future may, and even must, do things impossible in the past and acquire new motor variations not given by heredity.