Eace plays an important part; thus Jewesses, who belong to an unmixed people, menstruate at about the same age in all latitudes, i.e., at fourteen or fifteen years of age. Commingling of races develops a mean; thus Eurasians, or Anglo-Indians, i.e., half-castes with European fathers and Hindoo mothers, arrive at puberty earlier than pure Europeans and later than pure Hindoos.
Heredity does much to influence the age at which pubescence is reached; thus, some f amilies are notably precocious or notably tardy in development.
The state of the general health exerts a powerful influence; thus, if a child is suffering with any wasting or debilitating disease, or if pressed too hard by study, puberty is apt to be retarded and disordered. It is said that city bred children arrive at puberty about a year earlier than country children.
Until about the age of puberty, girls and boys are simply children, who in innocence play unrestrictedly together. The girls are at birth a little smaller than the boys, but at puberty they shoot ahead in both stature and weight, and with these changes in the body are associated corresponding changes in the mind, habits and inclinations, which are the signs of an earlier maturity in them. Until this change occurs there are no notable functional or psychical differences between the sexes, but the girls and boys associate intimately without any sensual ideas or longings, with their voices pitched in the same key, and with no marked dissimilarity of their skeletal structures.
Heretofore the whole energy of their minds and bodies has been directed toward "acquisition", and they are not "productive" in either thoughts or works. In each other's presence they are frank and simple, and are without any marked feeling of modesty or coyness. What gallantry the boy shows before this time is probably due to his education rather than to his natural tendencies, and what blushing timidity the girl displays is also more the result of external influences than of natural promptings. Though the boy is naturally more boisterous, and the girl more bashful, modest and shy, yet so far they are practically generis neutrius, neither male nor female, without any sexual impressions, and they have hardly entered within the portals of real life.
But now the greatest physiological era in their lives, next to that of birth, is about to raise a natural barrier between them, and send them along well defined roads diverging to manhood and womanhood. During this critical period, when life is yet young, they are initiated into new loves, new emotions, and even a new type of body; they are yet plastic, and good or evil habits are more likely to become fixed upon them now, and in the next few succeeding years, than at any other time in their lives. From now on the similarity between the sexes rapidly disappears; their undifferentiated sexual characteristics become strongly masculine or strongly feminine, and the psychical differences are even more distinctly developed than the bodily changes. These contrasts between the sexes come on gradually, and several years of adolescence are required before the sexual types of body are clearly defined, while even a longer time is expended in the evolution of the masculine and feminine types of intellect.
It is well recognized that this is a critical period, during which the hereditary influences for health or disease, for good or bad tendencies, for insanity or mental equilibrium, are most felt, and at this time especially, as Olouston says, "a man may fall a victim to his grandfather's excesses".
The change in the female is more profound than in the male, and the bodily disturbance of greater intensity; so much so, that few girls pass through this period without
marked constitutional derangements, or some of the multiform types of hysteria. Woman plays the more important sexual role in Nature, being more complex in physical structure, as well as in mental and moral organization. She conceives, gives birth to, and rears every individual, while man is very much less concerned in the perpetuation of the race.