=Mental Development.=—We note that at birth the brain is mindless, and that the brain-cells, which are the vehicle of the mind, undergo their greatest development during childhood from stimuli coming from without the body. The brain-cells possess infinite possibilities and potentialities. They are developed from the stimuli from without through the eyes, ears, touch, taste, and smell. There is another series of constant impressions which are received from within the body, and these come from the muscles. These impressions, conveyed to the brain-cells from the body, and from the outer world beyond the body, leave a fixed registration, the writing on the brain-cells has begun, and this constitutes memory; and the imprint on these cells is similar to that which type leaves of letters and words on the page of the printed book. These printed impressions on the cells can be revived and seen and heard by the mental consciousness, just as a printed book can be opened and seen and read by its owner. The natural qualities of the mind are imitation, acquisitiveness, emotionalism, and imagination. The force of example in the home, at school, and in the book world is among the most potent influences in molding character. The young girl instinctively imitates her mother, her friends in real life, and in her book world, and the woman will be the composite production, combining traits of all of these, which will be ingrafted on the ancestral traits which have been inherited. In young children it is difficult to decide where the imagination leaves off and the spirit of untruthfulness begins. In any case, the tendency to exaggeration and untruthfulness are so prevalent in childhood that it must be checked at the earliest signs of its appearance. The vice becomes so deep rooted that it affects the mind in all its workings and the entire life as well. It follows men and women into their business careers, their scientific life, and their professions. Professor Swift, in a very interesting study of the development of the mind, invokes the aid of biology to show that all children are but little animals, having no inborn notions of right and wrong, inheriting no sense of justice; savage, by nature, and predatory by instinct. He finds a psychic justification for fighting among boys. “Fighting in some form,” he says, “is one of the first means by which the mind becomes accustomed to intense action. To fight well, a boy must be capable of severe concentration of attention.” And he has found the age at which boys come to think that laws and the recognized rules of right conduct should be voluntarily respected varies from fifteen to seventeen years and older. These figures are approximately correct for girls.