THE ADRENAL GLANDS, THE GONADS, AND THYMUS
Like the pituitary, each adrenal gland is a double gland, that is,
consists of two distinct portions, united together, one might say, by
the accident of birth. It would be confusing, however, to speak of
each as two glands, because there are, as a matter of fact, two
separate adrenal glands, one in the right side of the abdomen, and the
other in the left. Each gland is composite, or duplex. How the two
parts came to be united is a long story, interesting but too long to
be recounted here. In fishes they are apart and independent.
Each adrenal is a cocked hat shaped affair, astride the kidneys,
easily recognized because of its yellowish fatty color. Indeed, for
centuries the glands were not given a separate status as organs, but
were passed up as part of the fat ensheathing the kidney. In childhood
and youth, in common with the other glands, they are relatively larger
and more prominent than in the adult. Also, at every age, the amount
of blood passing through them is very large compared to their size.
Their tremendous importance in the body economy accounts for their
being so favored.
The two parts of which each gland is composed, are known as the cortex
or outer portion (literally the bark) and the medulla or inner portion
(literally the core). No clean-cut boundary sharply delimits the two,
as strands and peninsulas of tissue of one portion penetrate the
other. In the history of their development in the species and the
individual, and in their chemistry and function, a sharp difference
contrasts them.
In the embryo, the cortex is derived from the same patch that gives
rise to the sex organs, the ovaries in the female, and the testes in
the male, described as the germinal epithelium. How intimately the
two sets of glands are connected is neatly pointed by this fact of a
common ancestor. All vertebrates possess adrenal glands. In the lowest
of the vertebrates, Petromyzon, the two parts are distinct, the cells
of the cortex-to-be are situated in the walls of the kidney blood
vessels, projecting as peninsulas in the blood stream, the blood
sweeping over and past them. The medulla-to-be consists of cells
accompanying the vegetative nerves. Among reptiles, the two become
adjacent for the first time, and among birds one part occupies the
meshes of the other. The size of the cortex varies directly with the
sexuality and the pugnacity of the animal. The charging buffalo, for
example, owns a strikingly wide adrenal cortex. The fleeing rabbit,
on the other hand, is conspicuous for a narrow strip of cortex in its
adrenal. Human beings possess a cortex larger than that of any other
animal.
No definite chemical substance has as yet been isolated from the
cortex. That remains a problem for the investigator of the future. But
certain observations, especially concerning the relation between
the development and behaviour of the so-called secondary sex
characteristics, those qualities of skin, hair and fat distribution,
physical configuration and mental attitudes, which distinguish the
sexes, and the condition of the gland, indicate clearly that an
internal secretion will be isolated, and that it will in its activity
furnish certain predictable features.
Three different layers of cells, arranged in strings, that
interpenetrate to form a network directly bathed by blood, that breaks
in upon them from _open_ blood vessels, compose the cortex. Most
remarkable is this method of blood supply for it is exceedingly common
among the invertebrates and rare among the vertebrates.
In certain disturbances of these glands, especially when there are
tumors, which supply a massive dose of the secretion to the blood
presumably, peculiar sex phenomena and general developmental anomalies
and irregularities are produced. If the disease be present in the
fetus, taking hold before birth, and so brought into the world with
the child, there evolves the condition of pseudo-hermaphroditism. The
individual, if a female, presents to a greater or less extent the
external habits and character of the other sex. So that she is
actually taken for a man, although the primary sex organs are ovaries,
often not discovered to be such except when examined after an
operation or death. How closely such an occurrence touches upon the
problems of sex inversion and perversion comes at once to mind.
If the process involving the adrenal cortex attacks it after birth,
the symmetrical correspondence and harmony of the primary sex organs
and the secondary sex characters are not affected. But there follows
a curious hastening of the ripening of body and mind summed up in the
word puberty, a precocious puberty, with the most startling effects.
A little girl of 2, 3, or 4 years of age perhaps will come to exhibit
the growth and appearance of a girl of 14. She begins to menstruate,
her breasts swell, she shoots up in height and weight, sprouts the
hair distribution of the adult, and the mentality of the adolescent,
restless, acquiring, doubting, emerge. A tot bewitched into puberty!
A boy of six or seven may suddenly, in the course of a few weeks or
months, become a little man, robust, rather short and stocky, but
moustached, with the muscular strength and sexual powers of a man and
thinking as a man. It is all as if into some fermentable medium or
solution a little yeast were dropped that changed the quiet calm of
its surface into a bubbling, effervescing revolution. It suggests at
once that maturation, the transformation of the child into the man or
woman, must be due to the pouring into the blood and the body fluids
of some substance which acts like the yeast in the fermentable
solution. The adrenal cortex is one source of the maturity-producing
internal secretions.
If trouble in the adrenal cortex starts after puberty, phenomena of
the same type, but of a different order, exhibit themselves. A woman,
say in the thirties, becomes thus afflicted. Slowly or quickly her
body will be covered by an abundant growth of hair, more or less of a
beard and moustache appear upon the face, her voice will become deep
and penetrating, her muscles will harden, and she will show a capacity
for hard physical labor. Sexually she appears to be made over,
masculinity now predominates in her make-up. Virilism is the name by
which the French in particular have popularized the knowledge of the
condition. Virilists have to shave or be shaved regularly and are not
bothered in the least by the cares, responsibilities, jealousies and
anxieties of personal beauty, for the change in their spirituality
makes them immune to the preoccupations of the feminine. The cause of
such a transformation in a previously entirely normal woman has been
found to be a tumor of the adrenal cortex.
But not only is sexuality, and the conduct of the secondary sex
characters, connected with the adventures of the adrenal cortex. The
development of the master tissues of the body, the brain, the pride
and darling of evolution, is in some subtle way correlated with
it. The adrenal cortex contains more of the phosphorus-containing
substances of the general nature of those found in the central nervous
system than any other gland or non-nervous tissues in the body. During
human intrauterine life the adrenal glands are large and conspicuous,
in the first half of the second month being twice as large as the
kidneys. Most of this relatively huge size, which happens in the human
alone, and not in other animals, is due to enlargement of the cortex.
Should this preponderance of the cortex over the medullary portion not
occur in the human, that is, if the proportions remain like those of
other animals, the brain fails to develop properly, or an entirely
brainless monster is generated. The human brain, therefore, probably
owes its superiority over the animal brain, to the adrenal cortex, in
development anyhow. The growth of the brain cells, their number and
complexity is thus controlled by the adrenal cortex.
Besides its action upon the sex cells and the brain cells, the
internal secretion of the adrenal cortex acts upon the pigment cells
of the skin, blunting their sensitiveness to light. In degeneration
of the interior of the gland, which destroys the medulla, but not the
cortex, the color of the skin is left unmodified. If, however, the
cortex is invaded, as happens most often in the classical tuberculosis
of the adrenals which drew the attention of the Englishman Addison
to them, then a darkening of the skin, which may go on to a negroid
bronzing, follows. That means an increased sensitiveness of the
pigment cells of the skin to light. Skin color control may therefore
be looked upon as an adrenal cortex function.
So much is known about the adrenal cortex. Upon the medulla, the
interior gland of the gland, there has been lavished an amount of
attention beside which the cortex is to be classed as a neglected
wall-flower. Nearly everything that possibly could be determined
about an internal secretion has in its case been settled or plausibly
guessed at. The cells manufacturing the secretion, its exact chemistry
and function, its action upon the blood, the liver and spleen, the
heart and lungs, the brain and nervous system, have been minutely
investigated, studied and charted. Its source in the food, its fate in
the body, its place in the history of the individual and the species,
its importance as a weapon in the struggle for existence, and the
survival of the fittest have been made the subject of an astonishing
number of researches, considering the short period of scarce three
decades that intensive science has centered its barrage upon it.
In the first place, the medulla contains numerous nerve cells,
belonging to the vegetative, also called the sympathetic nervous
system. But these nerve cells are merely minor notes of the symphony.
The motif is settled by a majority of large, granular cells, which
stain a distinctive yellowish-brown when the gland is fixed in a
solution of bichromate of potash. All chromium salts, in fact, stain
the therefore labelled chromaffin cells. The characteristic staining
power appears to be dependent upon, or correlated with, the presence
of the internal secretion of the medulla of the adrenal, adrenalin.
For the content of adrenalin, as calculated chemically, and the
depth of stain as seen under the microscope, rise and fall together.
Chromaffin reaction and adrenalin content go together. The poisonous
skin glands of the toad have been found to give a marked chromaffin
reaction, and to contain a large amount of adrenalin. Other masses
of cells in the human body, especially along the course of the
sympathetic nervous system, have been shown to give the reaction and
to contain adrenalin.
The erratic Brown-Séquard pounded and hammered away for more than
thirty years on the importance to life of the adrenal glands, since
death occurred so quickly after their removal. But it was not until
Schaefer, the Scotch physiologist, (who has done more than any other
living man to stimulate study of the internal secretions) found that
an extract of them, when injected into a vein, produced a remarkable
though temporary rise of the blood pressure, that a real enthusiasm
for its investigation was generated. As the upshot, a number of other
significant properties besides the first of blood-pressure raising,
have been put down to its credit. Chemical tests demonstrated that
it originated in the medulla. The exact amount of it present in the
medulla, in the blood issuing from the adrenals and in the circulation
in general have been determined. The concentration in the blood is
about one part in twenty million, while there is about a hundred
thousand times as much stored in the gland as reserve. In infections
and intoxications, after muscular exertion, and with profound
emotions, there is a decrease of it in the gland and an increase in
the blood. Pain and excitement, especially fear and rage, will bring
about its discharge from the gland. With its entry into the blood,
there is a tremendous heightening of the tone, a _tensing_, of the
nervous system. The nerve cells become more sensitive to stimuli,
more sugar is poured into the blood from the liver, more red blood
corpuscles are squeezed into the circulation from the blood lakes of
the liver and spleen. There is a redistribution of the whole blood
mass, a good deal of it being withdrawn from the internal viscera, and
hurried to the skeleton muscles and the brain. The heart beats more
strongly, the eye sees more clearly, the ear hears more distinctly,
and the breathing is more rapid. The temperature rises, the hair of
the head and the body becomes erect, the skin gets moist and greasy.
It will help a fatigued muscle to regain its normal tone. In short, it
has a reinforcing action upon the nutritive properties of the blood,
the tone of the muscles, and the activity of the brain and the
vegetative nerves.
Chemists set themselves the task of discovering just what was the
substance possessed of such extraordinary and hitherto unimagined
properties. The pure adrenalin was isolated, capable of evoking all
the reactions of the impure adrenal extract mixtures. The final
triumph was the preparation of it artificially in the laboratory,
its synthesis. When a substance can be synthesized in the chemist's
laboratory, it means that its composition has become thoroughly
understood. Here at last was an example of those mysterious internal
secretions, the existence of which had indeed been postulated and
proven, but which had never actually been inspected by the eye of
mortal man. To have it in a test-tube, indeed to possess it in large
quantities in bottles, to be able to manipulate and examine it without
fear of the co-action of admixed impurities, to see it with the eye,
and to taste it with the tongue, was truly a marvel. The miracle
aroused at once scores of researches.
THE GLAND OF COMBAT AND FIGHT
Considering its effects, one is reminded at once of the similarity
to the expression of a primitive emotion like anger or fear. So, by
turning a relation upside down, it was argued that if artificial
adrenalin could produce all these effects of an emotion like fear, the
emotion itself should produce an increase of the natural adrenalin in
the blood. This was found to be the case. Cannon of Harvard has built
up an entire theory of the adrenal as the gland of emergencies upon
the basis of these effects. In the facing of crises the adrenal
functions as the gland of combat. And indeed, as I have mentioned,
the more combative and pugnacious an animal, the more adrenal it has,
while the timid and meek and weak have less.
The Glands of Combat, the glands of emergency energy, the glands
of preparedness,--such are the adrenal glands when viewed from the
adrenalin standpoint. A picture of its activity in the evolutionary
scheme of struggle and survival is something like the following:
meeting an enemy, the animal is put in danger. It must fight or flee
for its life. In either case, certain conditions must be fulfilled, if
the body of the animal endangered is to be saved. To prevent injury to
itself, and to do as much injury as possible to the foe--that becomes
its immediate urge and necessity. Of the two animals, if in one the
heart should begin to beat more strongly, the blood pressure to rise,
the blood to flow more rapidly through the attacking instruments, the
muscles, the teeth and claws, the brain and its eyes, while the other
animal experiences none of these, the former will be the victor in
fight or flight. Adrenalin may be looked upon as the invention for the
mobilization at a moment's notice, or as we say, after generations of
use, by instinct, of all these visceral and blood advantages in the
struggle of combat or flight.
The nature of instinct, in its relation to the glands of internal
secretion, is a problem for another chapter. But we may note that the
James-Lange theory of an emotion regards it as a consciousness of the
very changes in the organism adrenalin causes. Since adrenalin is the
starter of the whole process, and since McDougal has defined emotion
as the feeling aspect of an instinct, just as an instinct may
be defined as the motor aspect of an emotion, the adrenals as
emotion-genetic, and instinct-genetic, play a part in the most
profound processes of the subconscious and unconscious.
THE MECHANISM OF FEAR
We may therefore visualize a mechanism of fear. An instant excess of
adrenalin occurs in the blood of, say, a cat when it is alarmed by the
sight of a dog. In that cat, at the image of its hereditary enemy,
certain brain cells vibrate. A nerve tract, in use as the line for
that particular message in a hundred thousand generations of cats,
whirrs its yell to the medulla of the adrenal gland. Through the tiny,
solitary veins of the glands, an infinitesimal quantity of the reserve
adrenalin responds. And with what an effect! The blood, that primary
medium of life, the precious fluid that is everything, must all, or
nearly all, be sent to the firing line, the battle trenches, the
brain and muscles, now or never. So the blood is drafted from the
non-essential industries--from the skin where it serves normally to
regulate the heat of the body--from the digestive organs, the stomach
and intestine, which must forsooth stop now, since if the organism
will die, their last effort of digestion has been done--from the liver
and spleen, great chemical factories in normal times, but now of no
moment. Besides, should they be wounded, it is better they should
be bloodless, and so run the least chance of bleeding to death, or
getting infected, for the more tissue there is around, the greater the
danger of infection. So, like the skin, the liver which usually holds
in its great lakes and vessels about a quarter of all the blood in
the body, is almost drained and blanched. At the same time, its great
storehouses of sugar open their sluices and pour into the blood,
increasing its sugar content by about a third because the combustion
of sugar is the easiest way of getting energy free in the cells, sugar
being the most quickly burned up of all the foods, and so the great
food of the muscles and the heart. The poisons of fatigue, acid
products of the contraction of muscles, are antagonized and
neutralized by substances formed in the course of the oxidation of the
sugar. Adrenalin, too, is directly fatigue antagonist. It causes the
blood to clot faster than under ordinary circumstances. It erects the
hair of the animal, and dilates the pupils of the eyes. There is an
increase of the apparent size, all of which are to intimidate the
enemy, like an Indian's painting of his face blue and green. It
also--but what else does it not do?
The story of adrenalin would have delighted the heart of Samuel
Butler. His "Note Books," opulent as they are, would have been the
richer in pages and pages with his comments on it. Contending as he
did with the pompous, dogmatic mechanism worship of the new scientific
clique of his time on the one hand, and the superstitions of the old
theological caste on the other, he had to fight the hardest kind of
guerrilla warfare in defense of the Purpose of Life. Adrenalin, that
weapon of a gland tracing its ancestry back to the begetter of the
brain itself, for brain and adrenal gland both have evolved from the
small nerve ganglia of the invertebrates, would have backed up to the
hilt his argument, which he had to elaborate on the indirect grounds
of analogy and induction. Essential for defense, and for protection,--
an organ in which everything necessary for the stratagems of retreat,
or the offensives of attack, are supplied ad libitum, while everything
non-essential or detrimental to the matter of the moment is inhibited,
arrested and suppressed--no more perfect sample of the design with
which Life is drenched could be imagined by the most closeted of
passionate idealists.
FAILURE OF THE ADRENALS
As the gland of acute stress and strain, the adrenals in modern life
are called upon to function more heavily and frequently than in the
past. As a matter of fact, the life of the beast of jungle and field,
as well as of savage and barbarian, is just as full of emergencies and
shocks as that of the average city man or woman. In the case of the
latter, however, inhibitions, education, and the conditions of modern
living, improper food, sedentary indoor confinement, and universal
rack and noise, have undoubtedly made greater and greater demands upon
the adrenal glands. Chemical quantitative studies have shown that by
repeated stimulation, the adrenal glands may be exhausted of their
reserve supply of secretion, which returns only insufficiently if not
enough time is given for recuperation. There results a condition of
temporary or chronic adrenal insufficiency, supposedly an insufficient
functioning of the gland as a whole. In persons so afflicted there
appears a fatigability, a sensitiveness to cold, cold hands and feet,
which are sometimes mottled bluish-red, a loss of appetite and zest in
life, and a mental instability characterized by an indecision, and a
tendency to worry, a weepishness upon the slightest provocation.
A certain number of the temporary breakdowns or nervous prostrations,
which seem to be growing more common or fashionable, may be sometimes
traced to such a deficiency of normal response to the needs of
everyday conflict by the adrenal gland. In some, mental and physical
elasticity are totally lost, and even the slightest exertion in
either field often causes so much weariness and exhaustion as to be
prohibited. Depression and even melancholia are associated with the
fear of not being able to accomplish good work hitherto easy and
enjoyed. Sometimes they are obsessed with the thought that they have
lost their nerve completely, and so dread to commit themselves in even
the most trivial of situations. The vacillating frame of mind is so
distressing at times as to arouse thoughts of suicide. When these
symptoms concur in the type of personality whom I shall describe
as the unstable adrenal-centered individual, there is evidence for
explaining the process as the effect of an insufficiency of secretion
by the adrenal gland.
Shock, collapse, heart failure and sudden death following abnormal
emotion, like an attack of rage, or the terrors of a railroad
accident, or bad news, or excessive exertion like running a long race
or climbing a high mountain when in poor general health, as the phrase
goes, or in the terminal stages of infections like epidemic influenza
or Asiatic cholera, have been put down to an acute insufficiency of
the adrenal gland. A lowered temperature, blood pressure, and blood
vessel tone, exhibited in tests of the response of the skin to
stroking, are present in all of these and point the same moral.
In the second half of the 19th century, an American physician, Beard,
described Neurasthenia, a general disturbance of the body and mind,
not properly classifiable as a disease, but serious enough to
incapacitate or at least greatly limit the sufferer. The neurasthenic
is to be recognized by the fact that the most painstaking objective
examination of his organs reveals nothing the matter with them. Yet,
according to his complaint, everything is the matter with him. He
cannot sleep when he lies down, he cannot keep awake when he stands
up. He cannot concentrate, but still he is pitifully worried about his
life. The slightest irritant causes him to go off the handle. As
he works himself up into his hysterical state as a reaction to a
disagreeable person or problem, irregular blotches may appear on
his face and neck. Generally, his hands and feet are clammy and
perspiring, his face is abnormally flushed or pallid, the eyes are
worried or starey, unwonted wandering sensations involving now this
area of the body, or now that obsess him. As the blood pressure is
too low for the age, the circulation is nearly always inadequate and
palpitation of the heart is a frequent complaint. So frequent, that
attention is often centered upon the heart, a diagnosis of heart
disease is made, and the unfortunate is doomed for life--to brood
over horrible possibilities. The brooding over themselves and their
troubles is one of the distinctive features of the whole complex.
Neurasthenia may masquerade as any organic disease. An individual with
a soil for a neurasthenic reaction to life will become neurasthenic
when confronted by any stone wall, including a serious ailment within
himself.
Beard's Neurasthenia leaped at once into the limelight. It was seized
upon and applauded in Europe as a good new name for an old condition,
observed particularly in Americans abroad to rest from the fatigues of
the get-rich-quick games of industrial speculators. In fact, the name
of the American Disease was given to it. Various theories about the
effects of climate, sunlight per square inch and unit of time, oxygen
content of the air, and so on, were offered up upon the altar of
scientific explanation. Sir Arbuthnot Lane, famous protagonist of
Lane's intestinal kink, said that all Americans were neurasthenic.
Neurasthenia became one of the most popular of diagnoses, and remains
so today.
Neurasthenia, regarded as a reaction of people to the stress and
strain of life, has without a doubt increased. The most casual of
observers will tell you that the generation of the Great War is a
neurasthenic generation. It takes its pleasures too intensely,
its pains too seriously, its troubles too flippantly. But what is
neurasthenia? Beard himself regarded it as a chronic fatigue and loss
of tone of the nervous system, a literal interpretation of his term.
That the conception, as far as it goes, is valid is proved by the fact
that it is the neurasthenics who furnish the majority of the clientele
of the cults, the Christian Scientists, the osteopaths and the
chiropractors, and who are the subjects of the faith and miracle
cures, like those of Lourdes. That is because their particular
disease, or what appears to them to be their very own disease--and
they certainly cherish their ailments--is but an expression of, a
compensation for, indeed a consolation for, the underlying feelings of
insufficiency or inferiority. Were there no moral code, were there
no social system, nor the consequent inculcated conscience to be
responsible to, there would be no such disguising symptom as
the disease which preoccupies the consciousness. The feeling of
insufficiency would be there, and would be recognized as in itself
the disease. To the physiologist and the psychologist, the feeling of
insufficiency is the disease, no matter how spectacular the overlaying
phenomena--a cripple on crutches or a man blind and speechless. Shell
shock is now acknowledged to belong to this group.
Now one of the outstanding effects of disease of the adrenal glands is
the feelings of muscular and mental inefficiency. And as a matter
of fact, a good number of observations conspire for the idea that a
certain number of neurasthenics are suffering from insufficiency of
the adrenal gland. The chronic state of the acute phenomenon, known as
the nervous breakdown, really represents in them a breakdown of the
reserves of the adrenals, and an elimination of their factor
of safety. In the light of that conception, the great American
disease--dementia americana--is seen to be adrenal disease--and the
American life to be the adrenal life, often making too great demands
upon that life, and so breaking down with it.
ADRENAL EXCESS
The converse of adrenal insufficiency, that of adrenal excess, also
exists. In certain types of the middle-aged, a high blood pressure,
accompanied by a great capacity for work, has been shown to be
associated with hypertrophy of the cortex. In women, there is a
degree of masculinity, as the adrenal in women makes for masculinity,
neutralising more or less the specifically feminine influences of
the internal secretions of the ovary. Such women possess a vigor and
energy above the normal, and command responsible positions in society,
not only among their own sex, but also among men. They are the ones
who, in the present overturn of the traditional sex relationships,
will become the professional politicians, bankers, captains of
industry, and directors of affairs in general.
THE GONADS
(_Sexual, Puberty or Interstitial Glands_)
The gonads is the name applied to the generative or reproductive
glands considered collectively. In the male, they are the testes; in
the female, the ovaries. They are, therefore, sometimes called the
sexual glands. As they possess definite canals for the removal of
their gross secretion, the specific reproductive cells, ova or
spermatozoa, to a surface of the body, they are first of all glands of
external secretion. But they have been also found to hold secretory
cells not concerned with the making of the reproductive corpuscles,
but, as all the evidence indicates, with the manufacture of an
internal secretion. These interstitial cells form the interstitial
gland. A classic example of a gland of internal secretion lodged in
the interstices of a gland of external secretion is thus furnished by
the gonads.
ORIGIN OF SEX TRAITS
The history of sex goes back far in the scheme of life. The
immortality of the ameba was at one time one of the indisputables of
biology. Then some observations were made which threw doubt upon a
long accepted fact, now declared a dogma. Lately, opinion has veered
back to immortality. But in the case of a close relative of the ameba,
the one-celled animal known as the paramecium, union with another
paramecium, true conjugation, has been proved necessary to prevent
death sooner or later. Sex here appears in its most primitive form, on
the basis of exchange of necessary materials, between individuals to
prevent death, their own having been, so to speak, worn out, in the
course of metabolism.
Specifically different sexes come later, when mortality is a universal
fate, as a means of rebirth and escape from death. Then the sexes
develop their latest function, most prominent among the younger
vertebrates, of acting as nature's most potent method of variation and
differentiation. In the pursuit of the different, nature has exalted
sex, and the intensity of the sex life. As far as the preservation of
a species is concerned, and the reproduction of the individual, the
asexual methods, budding, for example, would have done well enough.
But when it comes to enacting a different individual apart from the
effects of environment, sex stands out as the favored method of Life.
The development of the sexes and the sexual life brought a new element
of conflict into the living world. Before the advent of the sexes the
conflict was essentially for the means of existence, food alone. But
with the sexual life came a conflict for sex pleasure, a competition
among members of the same species for the same individual as their sex
partners. The result was the introduction of a factor in evolution
which Darwin examined so closely in the "Descent of Man."
The sex conflict has been the cause for the origin and the survival
of certain physical and mental traits, helpful in sex attraction, sex
combat, the growth of the embryo, and the nutrition and safety of the
young of a species,--in short, the whole process of sexual selection.
The proportions of the skeleton, the distribution of hair and fat, the
construction of organs of attack and defense, the color of the skin,
the cyclic processes of preparation for impregnation, the oestrus or
heat period in animals, the menstrual period in the human being, the
psychic reactions to danger and combat have all been thus determined.
That man is bearded while woman is not,--that woman has potentially
functional breasts while man has not,--the aggressive pugnacity of
man contrasted with the more passive timidity of woman, have all been
evolved in the sex struggle, surviving because most effective in that
struggle. These so-called secondary sexual characteristics are an
expression of the influence of the internal secretion of the gonads,
or the interstitial glands. Some call them puberty glands, because
their ripening initiates puberty.
We know that these interstitial glands, to stick to that name, (rather
than to the name of the puberty glands, since they serve not only
to induce puberty but to maintain maturity) are the actual primary
dictators of the process by which male and female are distinguished,
if not created. Castration was probably the first surgical operation
carried out for experimental purposes, suggested no doubt by a
curiosity concerning its effects. Trepanning of the skull, the
geologic record indicates, was done even by the cave man. But as an
experimental operation, castration seems to hold the primary position
in the annals of surgery.
Its effects noted, the satisfaction of one of the lower human
instincts, jealousy, popularised it. From the days of Semiramis,
eunuchs have been commonplace figures of the East, their function
definite: to guard the harems of the powerful. The age of Abdul Hamid
witnessed no diminution of the barbaric tortures by which children are
prepared for the profession. It is to the credit of England that in
its dominions in the Orient the practice has been abolished. But it
goes on even today. According to the best authorities, four out of
five of these victims at the auto-da-fe of a vicious human instinct
die immediately or soon after from exhaustion due to pain and
infection. Not all of the ancient nations countenanced the brutal
horror. The Hebrews placarded castration an unpardonable sin, making
it a sin to castrate even animals. Nor was any man so mutilated
permitted to worship in the house of the Lord (Deuteronomy xxiii, 11).
Yet we have evidence that the latter Jewish kings employed foreign
eunuchs in their harems, who often held the most important positions
as ministers of the court.
Besides the eunuchs, another group of people have presented material
for the study of the interstitial glands. These are the Skoptzi of
Russia and the Lipowaner of Roumania. Among them castration is a
religious ritual. Mankind has always been most brutal to itself in the
name of the ideal. These sects were founded because in the eighteenth
century an antipode of Joseph Smith and Brigham Young discovered this
passage in Matthew xix, 12.
"For there are some eunuchs which were so born from their mother's
womb, and there are some eunuchs which were made eunuchs of men: and
there be eunuchs _which have made themselves eunuchs for the kingdom
of heaven's sake_. He that is able to receive it, let him receive it."
He decided that he was inspired to spread the gospel of castration. A
sect was founded who thought that surgery was the easiest way to enter
the gates of Paradise, and they multiplied and fructified. The sect
exists today, and some of the most interesting studies of the internal
secretion of the interstitial glands have been made among them.
Related to acquired eunuchism is the condition of eunuchoidism, the
eunuchs which were so born from their mother's womb. Baron Larey, the
great surgeon of Napoleon's armies, was their first painter. He was
the only altruist Bonaparte said he had ever met in his life. He
portrayed a group of soldiers with peculiarly high-pitched voices,
smooth and hairless skins, and atrophied generative organs. A somewhat
similar picture is evolved in certain types of insufficiency of
the pituitary gland. Features of the picture are exhibited with
disturbances of the other internal secretory glands also, like the
thymus.
But a host of experiments and data prove the interstitial glands to be
the direct controllers of elementary sexuality and the specific sex
traits of male and female. Beginning with Berthold back in the first
half of the nineteenth century, who studied the fowl, a number of
observations have been made on the effects of excision, translocation
and transplantation of these glands.
The results of the experiments and observations can be summed up as
follows: if the male individual is castrated before puberty, that is,
before the advent of the sexual life, secondary sex qualities do not
develop. In males, the generative organs do not grow, hair on the face
does not appear, hair elsewhere on the body remains generally scanty,
the voice continues as high-pitched as the child's, there is more
or less muscle weakness, obesity, and mental sluggishness. In other
words, we have an effeminate man, technically a eunuch. In the
castrated female, the pelvis does not grow to the normal feminine
size, the breasts do not swell as they should, more or less hair comes
out on the face, the voice is low-pitched, and tends to be rather
husky, the legs are longer, and again, the mentality is dulled. That
is, a masculine sort of woman is produced.
In short, the castrated male takes on a feminine type, and the
castrated female, a male type. In either case there is also an
infantilism, a retention of the infantile mental traits, a lack of
development of the adult mental attitudes and reactions. Now, if
in the castrated male is transplanted an ovary, the positive
characteristics of the female are evoked, such as enlarged mammary
glands, and a tendency to secretion of milk. Experiments have also
been reported in which a uterus was also placed in such an animal,
with a means of entry, and pregnancy followed. If in the castrated
female a testicle is planted, the masculine traits become much more
marked and striking. A direct exchange of the male and female
rôles can thus be achieved. Castration after puberty cannot modify
profoundly structures like the skeleton which are already completed.
Yet it may unquestionably bring about definite retrogressive changes
in the secondary sex characters: reduction or loss of virility,
diminution of facial and body hair, and a general presenility or
hastening of senility.
How remarkably these interstitial cells influence the entire structure
and vitality of the organism is indicated by these facts. How much
they have to do with sexual impulses, sexual excitement, and sexual
desire, what the Freudians have popularized as the libido, and how
subtly they act upon the coming and duration of adolescence and
maturity, as well as sexual precocity and peversions, we shall
consider in a later chapter. But it is enough now to remember that
these interstitial glands are the primary dictators of the genital
sense and flair of the individual. In any attempt at measurement of
men and women, the quality and quantity of the internal secretion
of the interstitial cells must be respected as a fundamental
consideration. The womanly woman and the manly man, those ideals of
the Victorians, which crumbled before the attack of the Ibsenites,
Strindbergians and Shavians in the nineties, but which must be
recognized as quite valid biologically, are the masterpieces of these
interstitial cells when in their perfection. They are such solely
because of the right concentration in the blood of the substances
manufactured not only by these cells, but by all the glands of
internal secretion. For it cannot be repeated and emphasized too often
that the interstitial cells of the sex glands are most sensitive to
all kinds of other influences, and, in particular, the other internal
secretory organs. They may indeed be watched as an index scale or
barometer of the general tone of the whole internal secretion system.
Sex variations offer a variety of clues to variations, disturbances,
predominances and abnormalities in all the components of the ductless
gland association.
To take a single instance, the development of the long bones is
dependent upon the handling of food lime by the body. Eunuchs and
eunuchoids, that is, individuals with insufficient internal secretion
of the interstitial cells, have longer bones and more fragile bones
than the normal. Vice versa, those with an excess of the secretion
have shorter and thicker bones. The earlier the onset of menstruation,
which means puberty, the shorter the extremities, as the action of the
internal secretion of the ovaries closes the story of the growth of
the long bones.
The ovaries are a most important factor in the regulation of the power
of the organism to keep lime in the bones. If they over-secrete in an
excess which cannot be taken care of by the other glands of internal
secretion, the body loses lime, a softening and curving of the bones
occurs, and the most horrible deformities and tortures for the
sufferer. Taking out the ovaries has cured some of the afflicted.
Administration of the antagonizing gland extracts has helped others.
An Italian, Bossi, in 1907, used adrenal gland curatively. More
recently, a British student of the subject, Blair Bell, was given the
direction of the treatment, at long range, of a number of cases in
India, the land of chronic pregnancy with insufficient food, and
consequent oversecretion of the ovaries, with the typical softening of
the bones. At his suggestion pituitary was used successfully.
Some of the glands of internal secretion act as accelerators to the
sex glands. Others act as retarding antagonists. Among the most
important of the latter is
THE THYMUS
The thymus is the gland which dominates childhood. It appears to do so
by inhibiting the activity of the testes or ovaries. Castration causes
a persistent growth and retarded atrophy of the thymus. Removal of the
thymus hastens the development of the gonads.
Situated in the chest, astride the windpipe, it descends and covers
over the upper portion of the heart, overlapping the great vessels
at the base of the heart. It is a brownish red mass, which when cut
presents the spongy effect of a sweetbread. The more intimate view
of detail revealed by the higher powers of the microscope shows
conglomerations of the white cells of the blood known as lymphocytes.
But scattered through the substance of the gland, between these
lymphocytes, like the interstitial cells of the sex glands placed
between the sex cells, are peculiarly staining cells in whorls.
Of which there are many more in the thymus of embryonic and early
postnatal life, known after their discoverer as Hassal's Corpuscles.
They are believed by some to elaborate the specific internal secretion
of the thymus. Present in all vertebrates, there seems to be more of
it in the carnivora than in the herbivora, like the thyroid.
Concerning the exact function of the thymus, we are a good deal at
sea. The latest opinion about the results of extirpation even in young
and growing animals is that they are nil. Yet there is a certain
justification for proclaiming the thymus the gland of childhood, the
gland which keeps children childish and sometimes makes children out
of grown-ups. There is a quantity of data for that proposition. In
the first place, the curve of rise of growth of the gland seems to
coincide with the period of childhood, the curve of its decline with
the period of adolescence and the rise of the sex glands. In the
past, it was accepted, that with puberty the thymus atrophied and
was replaced by some sort of fatty tissue. Nowadays, it is held that
secretion cells persist throughout life. When the extent of this
persistence is too great, the gland being from five to ten times as
large as the normal, a number of other features become prominent to
make the extraordinary individual, the status lymphaticus, who amid
the hazards of life will react in an extraordinary way. He will be
taken up in the consideration of internal secretion personalities.
Then there are the varied and remarkable phenomena of thymus
enlargement and hyperactivity in childhood itself. When an enlarged
thymus is present in an infant, the initiation of breathing in the
new-born, the introduction of the newcomer to the oxygen of the air,
may be an exceedingly prolonged, difficult, matter. Such a baby is
said to be born blue, and the breathing may be stridorous for days,
becoming normal for a time, to be followed later by spells of trouble
in breathing, breathlessness or breathlessness with blueness, and
threatened extinction. Sometimes these spells come out of a clear
sky in an apparently healthy child. That some poison, probably an
oversecretion of the thymus, is responsible is shown by the relief
obtainable by X-ray shrinkage of the gland, or the surgical removal of
a part of it.
Moreover, the gland is influenced by and influences the factors
of body weight and growth with an extreme readiness and lability.
Deficient general undernutrition leads to rapid decline in its weight.
Back in 1858, the pioneer student of the thymus, Friedleben, declared
that the size and condition of the thymus is an index to be the state
of nutrition of the body. Underfeeding for four weeks will reduce it
to one thirtieth the normal. It seems to act as a storage and reserve
organ, affording some protection against the limitation of growth by
lack of food material. In exhausting or wasting disease, the weight
of the gland sinks much more quickly than other glands. Scattered
instances have been reported of children growing, putting on inches in
height and expanding mentally, when thymus was fed to them, in whom
every other measure previously tried had failed. A French study of
over four hundred idiotic children with normal thyroids reported that
over three fourths had no thymus at all. Everything points to the most
direct and close relation between the gland and nutrition and growth,
but with nothing tangibly definite like our knowledge of the thyroid
and the pituitary.
There is evidence that the thymus is involved in the health and
efficiency of muscle cells and muscularity. Certain tumors of the
thymus, presumably destructive of the gland substance proper, and
thus cutting off its secretion, are accompanied by a singular muscle
weakness and atrophy of the muscle cells, entirely out of proportion
to the general damage suffered by the other cells of the body when
affected by the poison of a malignant growth. Also, the thymus has
been discovered diseased in certain mysterious progressive muscular
wastings. A remarkable fatigability of muscles, which appears after
the slightest exertion, is a feature. The feeding of thymus has caused
muscle cramps which apparently depends upon an increased excitability
of the muscle nerve endings.
Feeding of thymus to some of the lower creatures of the animal kingdom
will completely hold up differentiation. Take the unfolding of the
specialized tissues and organs which transform the tadpole into the
frog and the chrysalis into the butterfly. A tadpole kept supplied
with enough thymus in a nutrient medium will swell into an
extraordinary giant tadpole, but will not change into a frog.
Recently, this experiment has been contradicted. Yet this effect
corresponds to the conception of its importance in childhood as a
retardant of precocity, physical and mental. Clinical observations
emphasize that in childhood it is the chief brake upon the other
glands of internal secretion which would hasten development and
differentiation, checking them perhaps for a given time and so
profoundly influencing growth.
THE PINEAL
The pineal is another gland which has been credited with similar
abilities and a like holding-the-reins-tight-in-childhood function
among the cells. Like the thymus, it has been supposed one of the
distinctive organs of childhood and to die with it. Generations of
anatomists solemnly asserted, repeating each other's mistakes with the
aplomb of the historians who declare that history repeats itself, that
the pineal body was a useless, wastefully space consuming vestige of a
once important structure. That was the view in that century of grandly
inaccurate assertions, the nineteenth. Not that they relegated it with
that statement to the limbo of the dull and the uninteresting. Quite
the contrary. They conferred upon it a distinguished romance and
mystery by identifying it as the last heir and vestigial remnant of
a third eye, situated in the back of the head, which may still be
observed in certain reptiles. Imagine it! Somewhere, stuck away in a
cranny of the floor of your head and mine, is this descendant of an
organ that once sparkled and shone, wept and glared, took in the stars
and hawks and eagles, and now is condemned to eternal darkness and an
ineffectual sandiness. Today, we have not discarded that view of its
history, but we know a little more regarding its composition and
function.
What and where is the romantic object? It is a cone-shaped bit of
tissue hidden away at the base of the brain in a tiny cave behind
and above its larger colleague, the pituitary. Microscopic scrutiny
reveals that it is made up in part of nerve cells containing a pigment
similar to that present in the cells of the retina, thus clinching the
argument for its ancient function as an eye. But the outstanding and
specifically glandular cells are large secreting affairs, which too
reach back to the tidewater days of our vertebrate ancestors, when
Eurypterus and other Crustaceans were engrossed with the fundamental
problems of brain versus belly. Besides these, there are the singular
masses upon which has been fastened the unnecessarily opprobious
epithet of brain sand. These, noted and commented upon from the
earliest times, consist of collections of crystals of lime salts,
sometimes small, lying about in discrete irregular masses, and
sometimes grouped into larger mulberry-like concretions, varying
much in size. These brain sand particles have become of practical
importance in the detection of pineal disease because they, like all
lime salts, will stop the X-rays, and so can be photographed.
For a long time, indeed up to scarcely more than a few decades or so
ago, the pineal was believed to have no present function at all, or at
least no ascertainable or accessible duty in the body economy. That
it might perhaps be, in a sense, a gland of internal secretion was
a despised theory. Then a classic case, the most extraordinary and
curiosity-piquing sort of case, with symptoms involving the pineal
gland, in a boy, was reported by the German neurologist, Von Hochwart.
That boy provoked a little army of researches. He came to the clinic
complaining about his eyes and other troubles which pointed pretty
definitely to a brain tumor as the diagnosis to pigeon-hole him.
Nothing extraordinary about him in that respect. But the story told by
his parents was quite extraordinary, even to the jaded palate of the
clinic professor and his assistants. They said that he was a little
over five years old, a statement conclusively proved correct at his
death. Up to the time at which his illness began, he had been quite
normal in size, intelligence and interests. But with the onset of his
misfortune, he had begun to grow, and rapidly until now he looked
and corresponded in all measurements to a normal boy of twelve or
thirteen. Hair developed all over his skin, most prominently and
abundantly in the typically hairy places of adults. His voice became
low-pitched, and most remarkable of all, his sexuality and mentality
precocious. He became capable of true sexual life and is said to have
asked many questions about the fate and condition of the soul after
death. On one occasion he remarked reflectively: "It is odd how much
better I feel when I let other children play with my toys than when I
play with them myself." Other statements attributed to him imply the
most astounding maturity of thought and mental process. Headaches
finally came, and he died about four weeks later. The cause of the
whole bizarre tragedy was found to be a tumor of the pineal gland.
As has happened before in medical history, no sooner was the one
prodigy reported, than a score of others of the same ilk sprang into
the limelight. Cases of precocious genital development, especially,
some of them occurring as early as the second year of life, were
linked with them. It is an interesting point to be noted that in
these, as in those started by an overaction of the adrenal cortex, it
is premature masculinity that is stimulated. The adrenal cortex must
be classed as a gland of masculinity. The pineal possibly acts as a
brake upon the adrenal cortex.
Very soon after the report of Von Hochwart's prodigy appeared, an
experimental research on the pineal was begun in New York. The pineal
glands of a number of young bullocks were obtained and used for
feeding, to see whether an overaction of the internal secretion
could be produced. Guinea pigs, kittens and rabbits were used. The
experiments covered about two years in time. Of a dozen small
kittens, the subjects outgrew the controls rapidly in activity, size,
intelligence, and resistance to intercurrent disease. Of ten small
rabbits, the controls weighed about a third less than the subjects,
which were strikingly clean, active, fat and salacious.
Feeding of the gland was then extended to a particular class of
defective children, children with well-shaped heads, normal eyes,
symmetrically functioning limbs, excellent digestion, strong muscles
and generally, normal, sometimes rapid growth. It is to them,
particularly when mental normality has progressed up to the eighth,
tenth or twelfth year and stopped, that the term "moron" has been
applied. They have been a hopeless lot, belonging to the limbo of the
incurables. Moreover, they, emphatically the physically normal ones,
differ from one another enormously in the extent to which mental
operations are possible. As all transitions and degrees exist, no
definite classification and subdivision of them has been made. Yet
ever since the cretin, once looked upon as an eternally damned
defective, was transformed by thyroid feeding into an apparently
normal being, there has been no dearth of effort to find the right
kind of internal secretion to fit their desperate situations, but in
vain. In defectives with definitely, organically damaged brains,
no result of course was to be expected. In those of any class over
fifteen, no response has been elicited by feeding pineal gland. In the
others the results have been contradictory.
A set of observations have related the pineal to muscle function,
inviting comparison of it with the thymus. There is a singular muscle
shrinking and deforming disease, known as progressive muscular
dystrophy, hitherto a complete and unsolved mystery. Newer studies
of the pineal in this disease during life by means of the X-ray have
shown it calcified, that is, buried in lime salts, which signifies put
out of business. Recently thus another hint as to its function has
been ferreted out.
The tadpole as a reagent to test out the growth effects of different
glands of internal secretion has also been employed for the pineal.
Ten-day-old tadpoles fed on pineal present a marked translucency of
the skin due to a retraction of the skin pigment cells. Now without a
doubt a number of as yet unknown growth and metabolic effects follow
exposure of the body to the complete gamut of light rays. The
interesting suggestion follows that the pineal influences the body by
varying the degree of light ray reaction.
The pineal, the ghost of a once important third eye at the back of
our heads, still harks back in its function to a regulation of our
susceptibility to light, and its effect upon sex and brain. So it
becomes one of the significant regulators of development, with an
indirect hastening or retardation of puberty and maturity according
as it works in excess, or too indolently. It appears thus the blood
brother of the adrenal cortex which also influences the skin pigment
and so susceptibility of the organism to light, brain growth and sex
ripening. It is interesting that Descartes, in 1628, considered the
pineal the seat of the soul.
THE PARATHYROIDS
Sometimes imbedded within the substance of the thyroid in the neck,
sometimes placed directly behind it upon the windpipe, are four tiny
glands, each about the size of a wheat seed, the parathyroids. For
long they were swamped in the nearness of their great neighbor, and
considered merely a variable part of it. There are some who contend
that even today. But it has been proven that they are separate,
individual glands, with a structure and function of their own, and a
definite importance to the body economy.
On the animal family tree they appear early, contemporaneously with
the thyroids. In the embryo they develop from about the same sites.
And very often they look very much alike under the microscope,
especially when the cells are in certain quiescent stage of secretion.
Yet they are wholly independent in nature, activity and business.
First experimenters upon the effects of removal of the thyroid were
confused by contradictory findings with different animals because in
some they would take out the parathyroids at the same time without
knowing it, and in others they would not. That possibility suggested,
more careful dissectors accomplished the job of extirpating the
thyroid while leaving the parathyroids intact and vice versa. In
consequence some definite information about the parathyroids is
available, even though their internal secretion has never been
isolated, or its existence established as more than an inference.
When the parathyroids are removed, an astounding increase in the
excitability of the nerves follow. It is as if the animal were
thoroughly poisoned with strychnine. The slightest stimulus will make
him jump, or throw him into a spasm. When the excitability of the
nerves is measured by an electrical instrument it is found augmented
by from five hundred to one thousand per cent. The reflexes, those
automatic responses of brain and spinal cord to certain stimuli and
situations, become enormously sensitive, so that merely letting the
light into a darkened room will make the subject of the experiment go
into a series of convulsions.
On the chemical side, an explanation for these nervous phenomena has
been advanced. Lime in the blood and cells appears to be necessary in
a number of ways. In the making of bone and teeth, in the coagulation
of the blood, in the keeping of fluid within the blood vessels, and
in maintaining the tone of the nerves, it plays a major rôle. Now the
parathyroids, among all the glands of internal secretion, seem to act
as the prime regulators of the amount of lime held within the blood
and cells. For when the parathyroids have been completely and
aseptically excised, without injuring any other organ, immediately the
body begins to lose lime. Something has gone out of it that helped
it to bind lime, and without that essential something, the internal
secretion presumably of the parathyroids, the lime departs. As
a conspicuous consequence the teeth fail to develop properly,
particularly as to their enamel, for which lime is an essential
constituent. Hair is lost, there is a general wasting, the nails get
brittle, and the bones soften, and the animal dies. Supplying lime
directly, particularly by direct injection into the blood, will
relieve the symptoms.
In man, a condition of nervous over-excitability has been described
as tetany. It occurs most often in the young, the pregnant, or in
vomiting after operations. All sorts of tests have related the malady
to the phenomena succeeding parathyroid deprivation, and they are now
looked upon as aspects of it. Individuals have been reported suffering
from an insufficiency of the internal secretion of parathyroids,
with a sudden extreme depression, nervousness and restlessness, an
inability to sleep or sit still, and a tremulous handwriting. Such
reports round out the evidence for the importance of the parathyroids
in an understanding of the factors which control growth, especially
as regards lime utilization, for without lime properly handled no
building of cells is possible. Also the parathyroids are necessary to
a steadiness of muscle and nerve.
THE PANCREAS
The business of the parathyroids concerns the keeping of lime in the
body. Another gland, the pancreas or sweetbreads, this time within the
abdomen, a close neighbor of the solar plexus, alias the abdominal
brain, is occupied with holding and hoarding sugar in the body,
particularly in the liver, the great sugar warehouse. This matter
of retaining sugar and controlling its output is one of the utmost
significance for growth and metabolism, the resistance to infections,
the response to emergency situations, and in general to the
mobilization of energy for physical and mental purposes. For without
sugar sufficiently at hand for the cells, no muscle work or nerve
work, the essentials of the struggle for existence, are possible.
The pancreas is an organ with both an internal and external secretion.
The external secretion, long known, evolved by the major portion of
the gland, is poured into the small intestine to play the star in
digestion. Scattered here and there among the definitely glandular
cell groups creating the external secretion are smaller collections of
cells, called the islets of Langerhans, which have been demonstrated
to elaborate the internal secretion. There are about a million of
these islands in each gland. The hormone has been called insuline.
Unlike most of the glands with a double secretion in which the
internal is absolutely independent, and so to speak, unconscious of
the external, these two of the pancreas are often disturbed together,
perhaps because trouble easily hits them both together.
Quite the most well-known disease due to disturbed internal secretory
function of the pancreas is diabetes. An enormous amount of work has
been spent upon the various aspects of it as a mystery. Hundreds of
papers in a dozen languages upon the subject are in existence. In a
nutshell, they have established pretty well that diabetes is a disease
in which there is an excess of sugar in the blood and urine because of
an insufficient amount of the secretion of the islands of Langerhans
in the pancreas. Removal of the pancreas makes the body, essentially
the liver, unable to retain sugar, as well as unable to burn up sugar
for energy. The situation is comparable to a locomotive with its coal
bins leaking, and the coal itself acting as if made of slate or some
equally uncombustible or only partially combustible material.
The control of sugar mobilization from the liver, where it is stored
as glycogen or animal starch, is divided between the pancreas and
the adrenals, the pancreas acting as the brake, the adrenals as the
accelerator of the mechanism. Adrenal and pancreas are therefore
direct antagonists, the pans of the scale which represents sugar
equilibrium in the organism. Diabetes may be regarded as a disturbance
of the adrenal-pancreas balance, assisted by events which produce
adrenal overwork like great or prolonged emotion, or by strain of the
pancreas, effected by over-eating for example.
There are other minor glands of internal secretions. But those
considered are by far the most important and the most recently
explored. In a summary, one would classify them as follows:
_Name Secretion Function_
1. Thyroid Thyroxin Gland of energy production
Controller of growth
of specialized organs
and tissues--brain
and sex
2. Pituitary-- Gland of energy consumption
and utilization--continued
effort
anterior Unknown Growth of skeleton and
supporting tissues
posterior Pituitrin Nerve cell and involuntary
muscle cell, brain and sex tone
3. Adrenals The Gland of Combat
cortex Unknown a. Brain growth--tone
development of
sex glands
medulla Adrenalin b. Energy for emergency
situations
4. Pineal Unknown a. Brain and sex development
b. Adolescence and puberty
c. Light and maturity
5. Thymus Unknown Gland of Childhood
6. Interstitial Testes in male Glands of secondary
glands of Ovaries in female Sex traits
7. Parathyroids Unknown a. Controllers of lime
metabolism
b. Excitability of
muscle and nerve
8. Pancreas Insuline Controller of sugar
metabolism