proper soil and care for it with skill; and with girls as with flowers the earlier the proper care is begun the more successful will be the result.

The Law of Development. From seed to blossom, from babyhood to young-womanhood, a growing life passes through a definite order of development. Help or hindrance at any given stage of growth affects each succeeding stage. Each individual living thing differs from others of its kind in the length of time taken to reach and to pass through various phases of its development, and in its amount of susceptibility or resistance to the influences which act upon it. Yet this variation is, within limits, sufficiently defined, so that even in varied seasons a gardener can count on average success with his carnations or cauliflower or primroses or potatoes. So a child may walk at ten months or at twenty, and she may read at three years or at six; but unless she is a cripple, she will walk before she reads. One stage of growth may be prolonged and another hastened by circumstances until they overlap, or through lack of opportunity some possibilities may never develop; it is this variation that makes the life of each girl we know so different and so fascinating. But if we know the general order of development of girl life from infancy to womanhood, the differences will be more intelligible. Any girl will be less puzzling if we look at her growth in the light of the great raceprocesses, where what is universal stands out from what is distinctly individual.

The Biology of the Girl Child. Every human life begins as one cell, a microscopic sphere of jelly-like life, which combines the physical and mental possibilities from the long lines of ancestry of both the

father and the mother. Life must grow, and this one cell gets larger and divides, and then re-divides. Each of these first cells has the marvelous possibility of making out of the food stuff provided it, muscles, or bones, or sense-organs, or nerves, or other tissues for a human body. Very soon this life-stuff with its multitude of possibilities divides in a more definite way. One tiny group of cells still contains all these undifferentiated possibilities which have come through parents and countless "greats" of grandparents. The other group has chosen out just one set of possibilities, which can build one human individual, with hair and eyes of a certain color, bones and muscles for a certain height, digestive organs with a sort of a chemical prejudice for certain food stuffs, brain cells that act quickly or slowly, sense-organs responsive to a certain range of sounds and colors-in short, all the things which make the girl baby "like" father and mother and kindred, and yet create her different, individual self.

Cells of the first group into which the germ divides are called reproductive cells. They grow comparatively little for many years, doing hardly more than to keep alive. Cells of the second group are the body cells (in scientific textbooks they are also called "somatic" cells), and they perform the marvelous feat of increasing from a size scarcely visible without a microscope to the bulk and complex mechanism of a baby's body and brain at birth, and then keep right on building food stuff into human life till adult size is reached.

The Individual Built from "Somatic" Cells. A writer has cleverly said that "a baby is not a personality, it is merely a candidate for personality." In the first dozen

years the girl baby achieves a very distinct personality. It cannot be complete until the first group of germ cells, hitherto inactive, has awakened and contributed its share, and it is this stage of building with which our study is chiefly concerned. It is this later stage, called adolescence, which develops the relation of the girl's personality to the race and to the world. But through childhood the "body cells" are building the individual, and this individual is becoming accustomed to the world of things and people about it. The business of childhood is to build a self, and in that sense only, childhood is "selfcentered"-but not necessarily "selfish." The business of adult life is to make the self count in the world of personalities for purposes bigger than the self. Adolescence is the time of change from one to the other. Sometimes this change in attitude never takes place, and the grown-up body has an undeveloped soul, using the larger physical and mental relations as a child would. In this failure is the root of all spiritual tragedy and social crime.

Whether this change to complete living comes at all, and whether it comes easily or with a great upheaval, depends on the direction of interests and habits in the years when the girl is in the making, body and brain, as an individual. What are the forces which determine this growth, and what is the order of their development? There are many popular books available which give information and help to parents and teachers of children. However, in order to use with skill the new forces of adolescence, it is necessary here to review the childhood forces and processes which remain at 2 See Bibliography, Numbers 58, 64, 65, 66, 69, 72, 77, 89.

work through adolescence, modifying and determining its results.

Individual Development Determined by Experience. At any stage of her developing personality the individual girl is what she has experienced. "Experience" is here used to sum up all the conditions which enter into the child's consciousness such as warmth, hunger, food, people who smile or punish, things that move or are still, that are hard or soft, edible or disagreeable, pretty or ugly, movable or out of reach. The girl's experience is determined by two things: what in the world of persons and things is within her reach, and what the mechanism of her body and brain makes possible.

A blind child cannot experience light, but neither can a child with perfect eyes, if she has never been out of a darkened room. A little girl in the tropics may be lithe as a panther, and a paralytic child in Norway may watch others skate every day, but neither one experiences skating.

What part of her surroundings a child actually experiences can be known to others only by watching her behavior. By "behavior" is meant some activity observable by another person: such as continuance or discontinuance of actions; speech; bodily or facial expressions; and the ways of thinking and feeling which determine these activities. Thoughts and feelings can be observed at first hand only by the individual who thinks and feels, but when that individual reports them in speech or gesture or writing, these reports become observable behavior.

The Relation of the Nervous System to Experience. "Experience" must first come to any individual

through impressions on the senses; not only the "five senses" about which we were taught in our childhood, but those tiny sense organs within as well as without the surface of the body which report temperature, pressure, movement of muscles and tendons, and probably a certain stimulation or irritation from chemical happenings within. In the last named are included those experiences, most difficult to analyze, of "wellbeing" or gloom that depend on the state of health; and sensations of sex.

"Behavior" implies the activity of muscles, whether of limbs or speech or expression, and muscle fibers act only when they are stirred by the action of a nerve. These impressions by way of the sense organs, and expressions by way of muscles, and the connections between them, depend on the organization and working of the nervous system. Like any system or tissue of the body, such as blood vessels, skeleton, or muscles, the nervous system is made up of "cells." These special nerve cells differ much in form and size, but they all have the power to conduct the energy they receive to other nerve cells till finally the nerve cell along which the energy is running ends in some group of muscle cells, which contract from the energy of that impulse. The structure of these nerve cells and how they form their connections is the subject-matter of physiological psychology. What concerns us is the fact that what an individual experiences depends upon the forming of these connections, and the readiness with which they work.

Sensory Stimulus and Motor Discharge. A single nerve cell, with all its extending branches and fibers by which an impulse may reach another cell, is called a