Mammary gland

“ There can be little doubt that the mammary gland was as apparently useless in the remotest male mammalian ancestor of man as in living men, and yet it has not disappeared. Is it then still profitable to the male organism to retain it? Possibly; but in that case its dysteleological value is gone.
In later editions Professor Huxley further observed: "The recent discovery of the important part played by the Thyroid gland should be a warning to all speculators about useless organs." ”

“ If through a surgical operation the breast from a male infant could be grafted in the proper place on a female infant, and the breast from a female infant on a male infant, the two individuals, as they became adult, would develop physically along the lines of his or her own sex except the grafted breast. That of the girl would remain flat, that of the boy would develop a mammary gland and become elevated into a mons. They each have on them a patch of the tissue of the opposite sex. In the passive invert there may exist one or more such patches from birth. ”

“ Mironoff found that, when the mammary gland is completely separated from the central nervous system, secretion, though slightly diminished, still continued. In two goats he cut the nerves shortly before parturition and after birth the breasts still swelled and functioned normally (Archives des Sciences Biologiques, St. Petersburg, 1895, summarized in L'Année Biologique; 1895, p. 329) . Ribbert, again, cut out the mammary gland of a young rabbit and transplanted it into the ear; five months after the rabbit bore young and the gland secreted milk freely. ”

“ In view of the intimate connection between the ovaries and uterus and mammary glands at other periods of life, it is in a high degree probable that many cases of active nutritive disturbances in the mammary glands, occurring about the forty-fifth year, are directly due to cessation. ”

“ The breasts are abundantly supplied with nerves and blood-vessels, and it must be evident that so great a functional power as that which is exerted by the mammary gland during lactation, must be supported by a great quantity of blood and nervous force. Hence it is, that during nursing, the breasts are supplied with a much larger amount of blood, and are much larger in volume than at other times. ”

“ Results
A total of 43 cat mammary lesion samples and 23 normal samples (14 blood and 9 normal mammary gland samples) were collected for this work. All of the cat mammary lesions analysed in the present work were clinically and histologically characterised (Table S1) . They included a collection of non-neoplastic and neoplastic lesions that represented a morphologically and clinicopathologically heterogeneous group of samples and were obtained over a two-year follow-up period (in the case of queens bearing malignant tumours) . ”

“ Moreover, a physician of wide experience has said that disuse of the mammary gland has a tendency to manifest itself in the next generation when the baby girl in turn becomes a mother, while the reverse is equally true. Impress upon her the fact that the milk is often slow in coming, and that nearly all mothers can, if they persevere and are in fair health, nurse their babies for at least three months, while a full year is better. ”

“ What seems to happen in fact, is this: the corpus luteum secretion stimulates the dormant cells of the mammary glands, formed during puberty, but latent until the advent of pregnancy. We know that injection of corpus luteum will cause an hypertrophy of the breasts. The same effect is produced regularly during the menstrual period, with a consciousness of swelling of the breasts. Their atrophy at the menopause coincides with the shrinkage of the ovaries that takes place at that period. ”

“ The sebaceous or fatty secretion from these follicles serve, during lactation, to shield the delicate part from the action of the saliva of the child’s mouth.
The milk-tubes, or excretory ducts, as they are anatomically named, are usually ten to fifteen in number; and as many as twenty-one is said to have been found in a single breast. These tubes commence by small openings at the apex of the nipple, and passed inward parallel with each other toward the central part of the breast, at which place they 372become enlarged, and branch off in every direction throughout the mammary gland ”

“ After the child-bearing period of life the breasts atrophy and tend to become pendulous, while in some African races they are pendulous throughout life. Variations in the mammary glands are common; often the left breast is larger than the right, and in those rare cases in which one breast is suppressed it is usually the right, though suppression of the breast does not necessarily include absence of the nipple. ”

“ The sympathy between the mammary glands and the uterus is now well established; it is shown in many different ways: in some women the application of the child to the breasts is immediately followed by after-pains, and in others these pains, which are usually but contractions of the womb to expel any clots that may have accumulated, are attended by a freer secretion or discharge of the milk. ”

“ In normal males the breast structure is present, but rudimentary, though it is not very rare to find instances of boys about puberty in whom a small amount of milk is secreted, and one case at least is recorded of a man who suckled a child. A functional condition of the mammary glands in men is known as gynaekomasty. ”

“ The nerves are the intercostals and phrenics.
Mammary Glands.—On the outside of the chest walls, lodged in the fascia of the pectoral muscles, are the mammary glands, accessory organs of the generative system. They exist in both sexes but are only rudimentary in the male. In the female they are small before puberty but enlarge as the generative organs become more completely developed, forming two hemispherical eminences, one on either side, between the third and seventh ribs. During pregnancy they increase once more in size preparatory to the secretion of the milk, and in old age they atrophy. ”

“ 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. ”

“ Perhaps the most remarkable of all somatic sexual characters are those which are almost universal in the whole class of Mammalia, the mammary glands in the female, the scrotum in the male. We have considered the evidence concerning the relation of the development and functional action of the milk glands to hormones arising in the ovary or uterus, now we have to consider the origin of the glands and of their peculiar physiology in evolution. ”

“ In the human female there is usually only one pair of glands, at the breast; and it is the same with the apes, bats, elephants, and several other mammals. Sometimes, however, we find two successive pairs of glands (or even more) in the human female. Some women have four or five pairs of breasts, like pigs and hedgehogs (Figure 1.103) . This polymastism points back to an older stem-form. We often find these accessory breasts in the male also (Figure 1.103 D) . Sometimes, moreover, the normal mammary glands are fully developed and can suckle in the male ”

“ The uterus diminishes in size; the vaginal cervix may disappear; the utricular glands diminish in size and number; the endometrium atrophies. The Fallopian tubes shrink and become shortened, and the fimbriæ disappear. Similar atrophic changes affect the vagina, the external genitals, and the mammary glands.
If the woman is in good general health, and has no disease of the uterus, the tubes, or the ovaries, the menopause may become established without any marked general disturbance. ”

“ That this hypothetical secretion starts from the womb rather than the ovaries seems to be indicated by the fact that removal of both ovaries during pregnancy will not suffice to prevent lactation. In favor of the ovaries, see Beatson, Lancet, July, 1896; in favor of the uterus, Armand Routh, "On the Interaction between the Ovaries and the Mammary Glands," British Medical Journal, September 30, 1899. ”

“ If a child lies constantly upon its abdomen, or is often found with its hands about the genitals, it may be at least considered in a fair way to acquire the habit if it has not already done so.
23. Lack of development of the breasts in females, after puberty, is a common result of self-pollution. Still it would be entirely unsafe to say that every female with small mammary glands had been addicted to this vice, especially at the present time when a fair natural development is often destroyed by the constant pressure and heat of "pads." ”

“ These variations in the number or structure of the mammary apparatus (mammarium) have become doubly interesting in the light of recent research in comparative anatomy. It has been shown that in man and the apes we often find redundant mammary glands (hyper-mastism) and corresponding teats (hyper-thelism) in both sexes. Fig. 103 shows four cases of this kind—A, B, and C of three women, and D of a man. They prove that all the above-mentioned numbers may be found occasionally in man. ”

“ A pair of substantial mammary glands has the advantage over the two hemispheres of the most learned Professor's brain, in the art of compounding a nutritious fluid for infants. ”

“ Mammary Sympathies.—As the breasts may enlarge from various causes—such, for instance, as the distension of the uterus from hydatids, or, as is the case with some women at each menstrual period, when the catamenia are suspended, or after they have ceased—this is by no means a sign on which much reliance should be placed. The change in the colour of the nipple and areola, more apparent in women of dark complexions, is more to be relied on as a diagnostic sign of pregnancy. ”

“ The last stage is that the centre of the mammary pit or saucer-like depression once more grows up to form the nipple, and at birth the processes become tubular, thus forming lactiferous ducts. The glands grow little until the age of puberty, but their full development is not reached until the birth of the first child. ”

“ The idiosyncrasy of the mother may affect the mammary secretion; and diseases, we know, exercise a direct influence, in proportion to their intensity, on the fluid secreted, and the effects are not slow to show themselves on the health of the child. Even a slight derangement of the digestive organs of the mother is apt to become transmissible by the milk, and the stools of the infant, from being of a natural appearance, suddenly assume a green or darkish tinge. ”

“ Pare says the wife of Pierre de Feure, an iron merchant, living at Chasteaudun, menstruated such quantities from the breasts each month that several serviettes were necessary to receive the discharge. Cazenave details the history of a case in which the mammary menstruation was associated with a similar exudation from the face, and Wolff saw an example associated with hemorrhage from the fauces. In the Lancet (1840-1841) is an instance of monthly discharge from beneath the left mamma. Finley also writes of an example of mammary hemorrhage simulating menstruation. ”

“ To sum up the normal pregnancy, we find that in the course of ten lunar months, following the fertilization of an ovum, the uterus grows from a small, flattened, pelvic organ, three inches in length, to a large, globular, muscular sac, constituting an abdominal tumor about fifteen inches long; it increases its weight thirty-two times, that is from two ounces to two pounds, while the capacity of the uterine cavity is multiplied five hundred times. Within the cavity is a child weighing about seven and a quarter pounds, surrounded by a quart or so of amniotic fluid. ”

“ The amount of post-pituitary secretion reaches a certain concentration. This in turn stimulates the thyroid and adrenal medulla. They in turn activate the ovarian cells, which congest the uterine glands and lining membrane. The follicle bursts, the ovum is discharged and wanders, the uterus waits and wonders. Nothing happens, the curtain is lowered, the scenery is removed, the actors revert to civilian clothes. That is the story of menstruation, the central phenomenon of woman's pre-pregnancy life. One sees it clearly as a play of an internal secretion syndicate. ”

“ The presence or absence of sterility, natural or enforced, always present, or say appearing after the birth of one child, must all be donated a prominent place in studying the endocrine make-up of a woman. When there is not enough ovarian secretion, the ovum may not be able to burst through the ovary, a necessity before it may begin its travels to the uterus. Next, the propulsive action of the genital ducts may be insufficient because of defective corpus luteum. Or the uterus may not have received enough posterior pituitary or thyroid to make it fit soil for the ovum to plant itself in. ”

“ The peculiar tissue growth within the uterus called decidua, which occurs normally in pregnancy and serves to fasten the developing ovum to the inner lining of the uterus, may be produced experimentally. This growth depends upon two factors, an internal secretion derived from the ovary and the introduction into the uterus of a foreign body of some sort; in the case of pregnancy the developing embryo acts as the foreign body. It is not impossible that some variation in the complex relations which determine normal growth may be one factor, possibly the most important, in tumor formation. ”