ABSENCE OF THE MAMMARY GLANDS (AMAZIA) AND SUPERNUMERARY MAMMARY GLANDS (POLYMAZIA).
Froriep and Schlozer saw congenital absence of the breast with coincident absence of the greater portion of the pectoralis major muscle and a union of the third and fourth ribs with the sternum. An infantile appearance of both mammary glands has been observed by Pears and Cooper, Caillot and Laycock, usually with coincident absence or incomplete formation of the ovaries.
More frequently there are more than two breasts (Polymazia, Meckel; Pleiomazia, Birkett). Sometimes this is only apparent, there being two or more nipples (Polythelia, 197/172 nipple) in different places on one breast. According to Meckel von Hemsbach there are originally in man five mammary glands (as is the case in the bat), two at the centre of the thorax, which alone go on to development; two in the axillary spaces, and a median one above the umbilicus and immediately under the sternum. Gorr( saw all these five breasts developed in a woman and Sanderson saw five nipples in these different situations in a man. Four mammte have been observed by Cooper, Lee, Shannon, Champion and Gardner. Dreger, Bartolin, Hannwus, Bone and M. Jussieu saw three mammas on a woman. Robert reports the case of a woman whose mother had had a double nipple, and she herself had a supernumerary milk-giving mamma on the outer surface of the left thigh. This case is scarcely to be explained by developmental history or by comparative anatomy. Those cases where in cows an udder on the back is found in connection with supernumerary extremities, are without doubt to be placed in the category of double malformations.
Leichtenstern, through his very careful investigations of such cases as have been reported, as well as by a series of cases seen by himself, has proved that the situation of these supernumerary breasts, (including the cases seen in the male sex,) is far more constant than has been thought. The reported cases of supernumerary breasts in the median line of the abdomen, on the acromion, and on the upper part of the thigh are very rare, and in part unique. Most supernumerary glands are situated below and somewhat internal to the normal situation, and very rarely in the axillary space. It is in the highest degree probable that these anoma lies are to be regarded as a reversion to other and lower types of animals, which normally have several mamnue, in fact, as a kind of atavism (Dar win), even though Meckel's opinion, that man originally had five breasts, would not be further confirmed thereby. Supernumerary breasts should only be removed when, on account of their situation or size, they become troublesome, or when the nipple is impermeable, and a lactiferous cyst is thereby developed, as in a case of Hares. There seems to be no relation between these anomalies and later diseases of the breast. I have, in all my observations, seen only one case in which a tumor (acinous carcinoma) has developed in a breast with two nipples. Precocious development of the breasts accompanies too early development of the sexual organs. Kussmaul (Wilzburger, Med. Zeits., Bd. II., p. 321) has collected these cases and critically examined them.