ADOLESCENCE IN THE MALE
ADOLESCENCE IN THE MALE.
The period of a young man's life from about fifteen to twenty-five
years, when he is growing from boyhood to mature adult life, is called
the period of _adolescence_. The period of adolescence is ushered in
by a series of physical and psychical changes which make a well
defined initial period called _puberty_. The period of puberty is
about two years in length, and in the average case among American
boys, covers the period between the fifteenth and seventeenth years,
and is completed when the youth can produce fertile semen capable of
fertilizing the human ovum. It is now universally recognized, however,
that when the youth reaches this point in his development, while he
may be called a man, he represents manhood in its lowest terms. He has
not reached either a physical or mental development or maturity which
justifies him in undertaking the responsibilities incident to
procreating his kind. It requires in the average case a period of
eight more years to develop the young man to the full stature of adult
manhood, possessing his full physical and mental powers and the
strength required of one who should assume the responsibilities of
parenthood, so that at the age of twenty-five in the average case the
young man may be said to have reached this period of complete
development and to have finished the adolescent period. We may
profitably now consider more in detail some of the changes incident to
this most important period.
1. PHYSICAL CHANGES.
General Changes in the Body.
a. =Pilosity.=--The human being belongs to the vertebrate class,
mammalia, and as a member of that class he possesses over the
cutaneous surface of the body, excepting the palms of the hands and
soles of the feet, hair follicles which produce the hairy covering
typical of mammals. A careful study of the distribution of the hair on
the surface of the human body, comparing it with that of the
anthropoid apes, demonstrates that the distribution is identical; and
the "lay" of the hair in any one region of the human body corresponds
exactly with that of the same region in the ape. For example--the hair
on the forearm points outward and upward; on the upper arm down-ward
and outward and so on throughout in the human and simian types. Every
child comes into the world with a coat of rudimentary hair which is
shed at once. Aside from the growth of hair on the head, including the
brows and the lashes, the skin is quite free from any noticeable
growth of hair for months or even years. Beginning at the age of
puberty, however, the growth of hair is very much accelerated over the
whole pilous surface of the body, particularly upon the face, in the
axilla and over the pubic region. It is a generally recognized law of
biology, that, at the period of sexual development, the hairy
mammalian character becomes accentuated. The increase in the growth of
hair at this time can have only one interpretation, viz., that the
ancestors of man represented a very much higher degree of pilosity
than is the case with man at the present time. It is interesting to
note in this connection the almost universal attempt of men to rid the
face of this hairy growth by various devices, either pulling the beard
or shaving it. The origin of this custom of depilation probably dates
back to the remote past and has been observed as a custom among both
savages and civilized peoples.
b. =The Voice.=--In all animals the voice plays an important part in
sexual and social relations. In many animals the voice seems to have
almost no other function than as a sex call, or a communication
between mates and between parents and young. The human subject
illustrates this general biological principle in the profound changes
which the voice undergoes at the time of puberty. These changes in the
male subject consist in increasing the depth of the larynx, thereby
increasing the length of the vocal cords which in turn modifies the
pitch of the voice, usually about an octave, making it not only lower
but much more pleasing in quality and greatly increased in volume.
c. =Bone, Muscle and Gland.=--Of incalculably greater importance than
the changes described above though perhaps less noticeable to the
casual observer, are those physical changes which the body undergoes
during the first half of the period of adolescence. I refer to the
growth of bone, of muscles and of those internal organs associated
with nutrition.
The first step in these profound physical changes is a rapid growth in
height that makes itself manifest about the fifteenth year. It is not
at all unusual for a boy to grow from four to six inches in a year.
This increase in height is very largely due to a lengthening of the
thigh and leg bones. In serial homology with the thigh and leg are the
bones of the arm and we find that these are undergoing an increase in
length commensurate with the increase of the legs. So the boy outgrows
his clothes; his coat sleeves are drawn up half way to his elbows and
his trousers half way to his knees. The muscles scarcely keep pace
with the bones in their growth, and tend to be flabby and to lack
usual tonicity. It is difficult for the youth to hold his back
straight and his shoulders back; he is awkward and ungainly in his
movements and becomes easily fatigued because of the condition of his
muscles. But the muscles follow immediately in their development and
rapidly gain volume and tonicity, filling out the arms, legs, back and
shoulders with large masses of firm muscular tissue. The growth of
these muscle masses changes the dimensions of the youth and he fills
out in his girths as rapidly as, in the previous period, he increased
in length measurements.
All of this increase in bulk can only be accomplished by increased
activity of all the nutritive processes. The appetite is practically
insatiable; the boy can eat three square meals in the day and lunches
between meals. If he wakes up in the night he is hungry. To accomplish
the digestion and absorption of this food material, the alimentary
tract throughout, and particularly the stomach is greatly increased in
size. To accomplish the distribution of the food (blood) the heart
also is increased in size and strength. With increased bulk of muscle
and increased quantity of food we have increased oxidation in the
tissues. This requires increased respiration, which demand is
satisfied by rapid development of the respiratory system. The thorax
increases in dimensions in all directions; it becomes deeper, broader
and longer. Not only does the thorax become more capacious but also
more mobile and more responsive to the varying requirements of the
system.
If we are interested in the biology of all these changes, we need not
go far to discover the natural causes at work to produce them. Nature
is preparing in the youth a home builder; it is preparing an
individual who can support and protect not only himself, but also a
family. This equipment in the case of primitive man must necessarily
be one of bone and brawn. While under the conditions of modern society
the necessity for bone and brawn is somewhat less marked, the plan of
nature is no less evident and no less interesting.
The Genital System.
a. =Structural Changes.=--The external genitals, besides showing the
pudendal pilosity referred to above, are all greatly increased in
size. The penis is increased in all of its dimensions, the testes
become very much increased in size, the scrotum, probably because of
the increased weight of the testes, is also lengthened.
b. =Functional Changes.=--The testes and associated glandular bodies
gradually develop the power of forming perfect semen, capable of
fertilizing the human ovum. When these organs thus become capable of
procreation, the period of puberty is complete.
In this connection it is important to note that the development of the
testes produces a profound effect upon both the physical and mental
characteristics of the young man. This effect is produced through a
substance formed in the testes and reabsorbed into the body, thus
gaining access to the blood where it exerts its mysterious but
profound influence. Just how this affects the mind and body will be
discussed in detail in a subsequent chapter.
2. PSYCHICAL CHANGES.
Play and Work.
a. =Sports.=--Most of the higher animals, particularly man, and all
races of men, devote a large part of the energies of the adolescent
period to sports or games in which individuals contend with each other
or teams of individuals contend with opposing teams in games that
bring into play the various powers of the neuro-muscular system: such
as alertness of all the senses, readiness and correctness of judgment,
agility, speed and strength of movement. Sports might be criticised by
some because they represent non-productive expenditure of energy. On
the other hand, no energy ever expended by man is so highly productive
of so precious a material as results from manly athletic sports. The
products of these games are the substances consumed by them,
paradoxical as that may at first appear. The use of brain, muscle and
glands and the consumption of the cell substances of these tissues
results in the development of the nerve, muscle and gland cells into
a condition larger, better equipped and more responsive than before
such use.
Thus, athletic sports, while they make draughts upon the nerves,
muscles and glands, develop all of these tissues to a high degree of
efficiency. The plan of nature in this instinctive indulgence in
sports must be evident. Nature is educating and developing the male
animal (man) to the highest possible degree of efficiency, so that
sports, instead of being non-productive, lead to the development of
structures possessing a high degree of value, not only to the
individual, but also to society.
Furthermore, those qualities of mind that are encouraged on the
athletic field between contestants in a game are the qualities that in
the later serious struggles of life make most for success.
b. =Productive Employment.=--Hardly less important than the influence
of sports is that of productive employment for the adolescent. That
the adolescent youth should not be assigned tasks that overtax his
physical or mental powers goes without saying, nor should he be
assigned tasks that consume so much of his time that he is unable to
take an active part with his fellows in field sports. However,
experience demonstrates that the youth undergoes a more wholesome all
around development if he takes some active part in a productive
employment, than if allowed to devote all of his energies to play.
The simple fact that he is held responsible for some duty about the
home or the shop develops in the youth not only a knowledge of how to
do things and a sympathy with the adults who are devoting their
strength largely to similar tasks, but--more important than either of
these considerations--these tasks develop in him the ability to
accomplish promptly and efficiently some piece of work as a duty--to
do it regularly and promptly because it is a duty without any
reference to a personal enjoyment in the task. If this important
lesson in life is learned during the early adolescent period, it will
make the path of life much less rugged than some seem to find it.
Society.
Incident to the activities of the athletic field, the youth is brought
into more or less intimate contact with fellows of his kind, both of
the same and of the opposite sex. While the boy of ten to fifteen
delights in the forming of "cliques, gangs and crowds," the boy of
seventeen delights equally in widening his circle of acquaintances.
The athletic contest gives him an opportunity not only to measure his
powers with those of the other young men, but also to win the respect
of his young lady acquaintances. There is no doubt but that the
approbation of his young lady friends for his prowess and strength as
manifested in sports, serves as a strong factor in the stimulation of
athletic contests and in bringing the sexes together in a purely
social capacity.
Religion.
While in his social relations the young man is seeking points of
tangency with those in his own plane, in his religious experience he
seeks to come into relation with his God; that is, with the power that
exists in the plane above his own. In the researches of Coe and of
Starbuck, made several years ago they discovered the following truth
and demonstrated it as a general principle: _(1) A vast majority of
professing Christians acknowledged their allegiance to God during the
early part of the adolescent period; and (2) a vanishingly small
percentage of professing Christians became so after the age of
twenty-five._