It is surely time, therefore, that some broad outline of the process of normal development of the whole nervous system should be possessed by all in charge of children. Every mother, for example, should know that the movements of a new-born baby, such as the facial contortions observed during sleep, or the stretching and bending of the limbs in very young infants, involuntary and automatic in character, constitute the simplest form of nervous activity. They are the necessary precursors of that intellectual ability, to the development of which parental ambitions aspire, and should merge into more advanced forms of nerve and muscle co-ordination, which, rightly utilised, are invaluable agents in infant education.[119] An intelligent nurse possessed of even this outline could begin quite early that training in physiological righteousness and in the strict voluntary control of the whole group of emotional expressions, of which, as a little reflection will quickly show, good manners largely consist. Presently, as the brain cells are stimulated into function by nutrition and a quicker and more extensive recognition of external sensations is acquired, a child will perform instinctive movements, such as sitting, crawling, standing, walking, jumping and throwing. Though considerable latitude must be allowed for their wide individual variation, failure to display these evidences of mental progress should call for careful investigation. Later on, skill in a hundred different forms of muscular activity should be displayed; but many years will elapse before full control of the body in all its parts will be acquired, and more years still must roll by before reasoned control of the mental and moral actions is developed. The last years of this long period of development are, perhaps, the most critical of the whole; though all depend for their favourable fruition upon an infinity of loving care and suitable provision for their appropriate activities. There would be a marked reduction in exhausting disciplinary difficulties were every parent aware that, to the almost vegetative character of the first few post-natal months (when sleep will or should absorb at least twenty hours out of the twenty-four), will succeed a period of extraordinary activity, which lasts till about eight or nine years of age, when the mind is essentially an exploring organ; imitative, impressionable, retentive. Every legitimate opportunity for the liberal gratification of these characteristics should be provided, as well as suitable surroundings for the eager, inquiring brain. Elaborate toys are not necessary, nor is premature book-learning permissible; but freedom to investigate, to experiment, to test, to explore, is the child's urgent need, as well as suitable arrangements for the intervening periods of profound sleep. Repressed activity is often responsible for breaches of discipline; so is insufficient sleep, following on over-excitement, accountable for "temper" and passions.