(From Mammae 4840 mamma, plural mamma).

The breasts. In the breasts we distinguish the mammillae, or nipples, the areola, the brownish circle around the nipples, and the lactiferous vessels. The .breasts are composed of a glandular substance and fat; the glandular part is hard, white, and irregularly mixed with fat, seemingly composed of tubes called tubi lac-tiferi. See Lactiferi ductus.

Though the breasts are usually spoken of as single glands, they are in reality a congeries of glandular bodies, of a small size, and a somewhat flattened shape. Mr. Cruickshanks has described them as acini; but other authors, with more reason, have supposed these small bodies to be merely convoluted vessels. From these small glands tubes emerge, which enlarge and anastomose freely; but, when approaching the nipple, near the areola, contract and open by distinct apertures. Fifteen of these are often counted on a small nipple, though other anatomists lessen the number. The areola is covered with a skin much more soft and fine than that of the general surface, resembling rather the ephelion of the lips and mouth, and interspersed with sebaceous glands, obvious even to the sight, to defend this tender covering from the pressure and the saliva of the child's mouth. The nipple itself is formed of a congeries of these small tubes. The different vessels, either lactiferous or secretory, are minutely divided by fat, and thus give the roundness, the fulness, and firmness of a well proportioned mamma.

The colour of the areola greatly differs even in different women; and, in some, it is so brown, as even in the natural state to give a suspicion of impregnation. (See Medicina forensis.) In chlorotic and unhealthy women it is pale; in the Samoeids and negresses black; and in brown persons of a deeper colour. The hue is evidently derived from a fulness of the arteries, though in what manner it is modified we cannot easily say; probably by the colour of the rete mucosum; for all the sexual organs have a brownish tint. In women of the most brilliant and delicate complexions, the colour of the areola resembles that of a rose.

The female mamma sympathizes very pointedly with every part of the genital system, generally with the clitoris, more sensibly and strictly with the ovaria and the uterus. At the approach of the menses the breasts enlarge; at their cessation they wither. After the lochia cease, the milk begins to flow, and this connection is so intimate, that it has been attributed to the anastomosis of the extreme branches of the epigastric and mammary arteries on the abdomen. This is, however, highly improbable; for their union is inconsiderable, and not peculiarly distinct at any particular periods. The sympathy, however, is so striking, that the Hottentots and the Scythians (Herodotus) irritate the vagina to increase the flow of milk from their cows and mares. It is highly probable that the milk is carried to the nipple, and often discharged from it by the action of its own vessels, and that the child drains the breast, not so much from its own powers, as by exciting the action of the lactiferous tubes. Thus a sensation is felt, when the child approaches, of some internal commotion of the mamma, which females distinguish by the term warping, and they are excited so much by the irritation of the vagina, as to render it doubtful if it is always prudent to deprive the hireling nurse of the company of her husband. A sentimental feeling also influences the secretion: thus the milk does not flow so freely on the application of a strange child as of a woman's natural offspring; and exciting the attention, especially if this is accompanied with a little terror, will wholly suspend the discharge.

The connection of the secretion of milk with the general state of the nervous system is also strongly marked. The maternal office of suckling is always attended with a calm serenity of mind, scarcely felt in other situations, and the suppression of the milk, on its first appearance, with irritability, languor, or despondence. The last, indeed, sometimes attends the period of suckling, though the milk continues to flow, from causes that cannot be ascertained. It seems to affect the young and the strong, rather than those of the middle period of life, or of weaker constitutions; the first lyings-in rather than future ones. The apprehensions of death, in those rare and inexplicable cases, are, however, so strong, that nothing can conquer them: the dejection so firmly fixed as to bid defiance to medical aid. In some cases it has continued for some years, but another pregnancy is usually an infallible cure.

Though the final cause of the connection of the uterine with the lactiferous system is obvious, yet, as usual, nature acts by general laws. Thus a false conception is attended with a fulness of the mammae, and the want of ovaria, as we have seen, has occasioned the breasts to remain in the state of the earliest periods. The irritation of a cancerous tumour in the uterus has, however, no effect of this kind, for it seems of a sedative nature; or perhaps the principium and fons of the irritation must be in the ovary.

It is a circumstance singular and inexplicable that men should have all the organs which produce and convey milk like women. Is it that the sex is determined after the rest of the body is formed, or that, in cases of necessity, men should be able to supply the office of the woman? The first is highly improbable; and though we have one instance of a man affording his motherless offspring this sustenance, the experiment has not been again tried, or not succeeded. Yet, on birth, when all the fluids begin to circulate freely, male children, as well as females, have often milk in the breasts. On the whole, were men subject to a partial plethora like that which takes place in menstruation, and were there an established sympathy between the breasts and genital organs, it is probable that they might become nurses. But neither the plethora nor the sympathy exist; and though we have found tumours in breasts of men, we have never heard of their becoming cancerous. Girls of the best character, by the irritation of a child sucking, have become able to support it. A woman of sixty-eight is recorded in the Philosophical Transactions to have suckled a grand child; and one of eighty, in a Swedish Journal, is said to have performed the same office. Russel mentions a similar fact respecting a barren sheep, in his treatise De Tabe Glandulaii, p. 64.

The number of teats in different animals correspond to the usual number of their young; but it is singular that, however the numbers differ, they are always even. Animals that do not give suck are generally oviparous; but some of the vipers, and some reptiles styled viviparous, are not strictly such; for their young are inclosed in eggs, which are hatched some time previous to the birth. A step between these and animals who are really viviparous may be observed in the didelphis, of which the kangarou is a species. These animals produce their young in an unformed, imperfect state; but they are for a long time concealed, and protected in a second uterus, formed under the belly by a duplicature of the skin, in which the nipples are found. While thus speaking on comparative anatomy, we may add, that the horse was supposed to have no nipples; but Dau-benton discovered them under the prepuce.

The arteries and veins are ramifications from the ar-teriae and venae subclaviae, and from the axillares. The nerves are principally from the costales, which communicate with the nervi sympathetici. The lymphatics pass through the axillary glands, though Meckel suspects that he has traced them into the subclavian veins. See Kolpin de Structura Mammarum, Sabatier Traite danatomie.