the definite date of beginning of puberty in boys is more difficult to determine, because they do not experience any definite, easily-apparent function like the menstrual period of the girl.

While Italian, Greek, and Spanish boys become adolescent at twelve to fourteen and Scandinavian boys at fourteen to sixteen, the mixed nationalities in America show an average age of onset of about fourteen, and a large proportion of American boys enter puberty during the fourteenth year.1

In the above paragraphs the terms puberty and adolescence have been used apparently interchangeably; but while the onset of puberty and adolescence coincide in time, the term puberty is properly applied to the period of three or four years during which a youth becomes thoroughly established in the development and functioning of the sex apparatus. This period of puberty occupies the first three or four years of the adolescent period. The terms puberty and adolescence are therefore not synonymous. Adolescence is the longer period and includes the three-year period of puberty as well as a four or five-year post-puberty period. The following diagram indicates the age limits of the five "ages" or periods from birth to maturity:

The post-puberty phase of adolescence is devoted to the maturing physical organs and tissues and the training of their powers; so that by the time a young man reaches twenty-two and a young woman reaches twenty we expect them to show full maturity of every organ and of every physical and mental power.

PreAdolescence

Differences
between
Boys and
Girls

It will contribute much to the clearness of our understanding of adolescence if we have a clear picture of the boy and girl before they cross the threshold into adoles

cence.

There is a well-defined period or stage of development preceding adolescence that is called the pre-adolescent or pre-puberty stage of development. The period lasts three or four years and extends, roughly speaking, from ten to fourteen in boys and from nine to thirteen in girls. It seems to be a general law of nature that the transition from one stage or phase of life to the next is never a sudden one, showing rapid and extreme changes; rather nature's transitions are almost always very gradual. We can, therefore, get a clearer picture of the typical pre-adolescent by picturing a boy of twelve and a girl of eleven than by picturing a boy of fourteen and a girl of thirteen, or a boy of ten and a girl of nine. In other words, we get the most accurate picture by selecting a subject from the middle of the period.

The boy of twelve is usually not appreciably larger than the girl of eleven; and as was demonstrated by H. P. Bowditch, of Harvard University Medical School, about 34 years ago, the measurements and general appearance of the boy and girl above mentioned are strikingly alike. They are quite apt to be interested in similar sports and games and to enter vigorously into them without any marked differences between the two as to activity and efficiency. The twelve-year-old girl is almost sure to be superior to the twelve-year-old boy in active sports and larger than he in all her physical measurements.

However, despite physical and functional similarities between the boy and girl of the mid pre-adolescent period, there are some interesting temperamental differences. Boys are almost sure to be interested in pets;-as rabbits, guinea pigs, dogs, goats, ponies, etc. Girls are much less interested in live pets; their interest is in dolls. The boys are interested in such activities as scouting, fishing, trapping, camping-in short, in woods-lore and water-lore in general. Girls of this age are far more interested in playing house, "going calling" and in giving doll parties.

One interesting phase of pre-adolescence is that while there is a definite sex consciousness there is not a reciprocal sex attraction. The boy thinks of the girl as "girl," but he does not seek close social relations; in fact, both boys and girls of this age are very unsocial toward each other. If one wishes to spoil a boy's birthday party just invite some "nice little girls" to come. By the same mark, if one wishes to spoil a little girl's birthday party, just ask some "rough, blundering boys" to come.

Boys of this age are almost sure to exhibit thoughtless cruelty, as, for example, pulling the wings from butterflies to see how they can navigate without them, or pulling the legs from grasshoppers with a similar object in view, or robbing a bird's nest to add the eggs to their collections.

Furthermore, boys of this age are very likely to drift or to be led easily into vulgarity. As the cruelty of the boy is due to his thoughtlessness, similarly his vulgarity is due to ignorance. He is not inherently either cruel or vulgar; he simply does not think things through. In short, the boy is a young barbarian. As to morals, he is unmoral, rather than immoral. As to social instincts, he is unsocial rather than anti-social.

Traits

Having sketched the outlines of a picture of the Adolescent typical pre-adolescent, let us now do the same for the adolescent. As there was an advantage found in selecting a mid pre-adolescent for our picture, so it will be advantageous to select a mid-adolescent, say a seventeen-yearold youth and a sixteen-year-old maiden. This youth and maiden are probably in the third or fourth year at high school. Physically, the youth has made a remarkable growth in the five years since we last observed him. He is perhaps five feet and eight inches in height, broad

shouldered, deep-chested, hard-muscled and fiery-eyed, a good all-around athlete. He must use a razor at least three or four times a week to keep his beard in order. He is much more likely than his sister to be interested in mechanics, electricity, radio, and in the mechanism and running of autos and motor boats, in canoeing and sailing, in hunting with gun and dog and in fishing with rod and reel.

He is socially not only quite conscious of the femininity of his girl classmate and associate in school, but he wishes to associate with her. This wish is evidently reciprocated. There is at this age not only sex consciousness but also reciprocal sex attraction.

Morally the mid-adolescent youth has experienced an awakening; he is no longer unmoral; either he is definitely and positively moral and ethical or he is definitely and positively immoral and unethical. The reason for this moral consciousness is in all probability due to the fact that the youth of seventeen is beginning to be thoughtful, and in his thinking of things that he observes, he reaches logical (or near-logical) conclusions; and he is acquiring a tendency to shape his line of action in accordance with the conclusion which he has reached.

The maiden of sixteen is now quite definitely a young lady. Her figure is attractive as a rule and she is graceful in her movements. Her measurements, as shown in the study by Bowditch referred to in a foregoing paragraph, and also demonstrated by W. W. Hastings (Manual of Physical Measurements, 1902), show a remarkable modification. She is perhaps five feet, three inches in height; her pelvic measurements are, relative to her other girths and diameters, much increased. Also the girth and depth of chest at the fifth rib level are greatly increased relatively because of the development of the breast. Her head is adorned with a wealth of glossy hair.

Mentally, she is likely to be especially interested in music, art, and the domestic arts and crafts. Morally, she is likely to have high ideals and altruistic motives. Socially, she is sensitively conscious of her femininity and the virility and manhood of her young men acquaintances and friends, and is happy to meet with them socially.

Contrasting the typical mid pre-adolescent with the typical mid-adolescent of each sex, we note that a remarkable change has taken place. The boy has become a young man, and the girl a young woman. The young man is typically man; the young woman is typically woman. The young man could father a child, the young woman could mother a child. Each one is sexually

mature.

What has wrought this remarkable change?

It has been known for thousands of years that if the sex glands be removed from a young male of any of the higher mammals, the male so treated does not develop the physical and psychical qualities typical of the male. In the orient in ancient times, most of the males of the domesticated animals were castrated or surgically deprived of the sex glands, of the testes or gonads. The reader is probably familiar with the frequent references in history and literature to the eunuch, who is simply a male from whom the gonads have been surgically removed.

One would think that in the long ago men would have thought the matter through and would have concluded that the gonads must produce some substance which, absorbed into the system and distributed through it, cause the development of the qualities and attributes distinctive of virility. Removing the gonads, thus depriving the organism of the influence of the glands, would profoundly influence development. But if anyone thought the matter through he did not make any experiments and describe them; for it was not until late in the nineteenth century that it began to dawn upon the minds of

What Has Made the Boy a Man and the Girl a Woman