MAMMARY gland, in anatomy, is a glandular substance situated in the breast, and secreting the milk.
This gland, surrounded by cellular and adipous substance, and covered by the common integuments, constitutes the breast. It lies on the anterior surface of the pectoralis major muscle.
In men, and in young girls, these bo dies are small ; they enlarge in the female subject very considerably at the time of puberty, assuming an hemispherical shape, and pretty firm consistence, which, how ever, is lost as the subject advances in years, particularly in women who have suckled many children.
The skin of the breasts is white, and soft to the touch, except in the middle, where there is a portion of a reddish brown colour, called the areola. From the centre of this the nipple projects, in the form of a cylindrical prominence, with a rounded end, similar in colour tc the areola, and covered, like that part, by a more delicate continuation of the skin, which is somewhat wrinkled and in regular on its surface. Both the areolo and nipple are furnished with numerous sebaceous glands, which may be clearly seen through the integuments. The mat
ter which these secrete, preserves the parts from the excoriation which they would otherwise suffer from suckling The mammary gland is composed of ; vast congeries of small tubes, convolutes and accumulated on each other, anc known by the- teehniral names of tubill lactiferi. These unite together, gradually forming larger and larger trunks, which approach from all sides towards the nip ple. The trunks become very much con tracted at the areola, and in this state pass through the nipple, to terminate on its surface by open orifices, about fifteen in number, whose size is about sufficient to admit a hog's bristle. This structure can only be shewn during the period of suck ling.
The use of thy milk secreted in these glands, as a nutriment for the young ani mal, is known to every body. It is singu lar that they should exist in the male, where they never perform any office whatever ; at least, except in very rare instances, where a fluid of a milky na ture has been poured out from them.