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.

Puberty for a girl is like floating down a broadening river into an open sea.

Every theory of love, from Plato down teaches that each individual loves in the other sex what he lacks in himself.

Man is largely a creature of habit, and many of his activities are more or less automatic reflexes from the stimuli of his environment.

Being an only child is a disease in itself.

Muscles are in a most intimate and peculiar sense the organs of the will.

Adolescence as the time when an individual ‘recapitulates’ the savage stage of the race’s past.