. The comparative anatomy of the domesticated animals. Veterinary anatomy. GLAND-VESICLES, WITH THEIR EXCRETORY ULTIMATE FOLLICLES, OR GLAND VESICLES, DUCTS TERMINATING IN A DUCTUS LAC- WITH THEIR EPITHELIUM OR SECRETING TIFEROUS: FROM A MERCURIAL INJECTION; CELLS, a, a, AND NUCLEI, b, b. MAGNIFIED FOUR TIMES. Placed at the base of the teat, the galactoferous sinuses or reservoirs are generally two in number, but sometimes there are three, and even four; they nearly always communicate with each other, and are continued into the mammilla by an equal number of independent excretory canals—the de
. The comparative anatomy of the domesticated animals. Veterinary anatomy. GLAND-VESICLES, WITH THEIR EXCRETORY ULTIMATE FOLLICLES, OR GLAND VESICLES, DUCTS TERMINATING IN A DUCTUS LAC- WITH THEIR EPITHELIUM OR SECRETING TIFEROUS: FROM A MERCURIAL INJECTION; CELLS, a, a, AND NUCLEI, b, b. MAGNIFIED FOUR TIMES. Placed at the base of the teat, the galactoferous sinuses or reservoirs are generally two in number, but sometimes there are three, and even four; they nearly always communicate with each other, and are continued into the mammilla by an equal number of independent excretory canals—the definitive duets, whose orifices are very small, and are seen beside each other at the free extremity of the teat. A fine mucous membrane lines the inner face of this excretory apparatus; it is doubled in the teat by a thick layer of tissue, which again is covered by the skin that adheres closely to it. (Between the external and internal tunic of the teats, are found numerous fasciculi of unstriped muscular fibres, arranged in a circular and longitudinal manner around these ducts.) Connective tissue, vessels and nerves, complete this organisation. (The arteries are from the external pudic trunk; the veins are very numerous, and pass to the trunk of the same name; the nerves are derived from the first F'§- "^l^- lumbar pair.) Fl'nctions.—Tlie mammfe secrete the milk; they undergo remarkable modifications at puberty and at the end of each gestation—modifications which are related not only to their volume and secretion, but also to their minute structure. After ges- tation, the gland-vesicles shrink: become, as it w^ere, atrophied, and have only a polygonal epithelium. At the termination of gestation, they are enlarged, new vesicles are de- veloped, and the epithelium changes its character: filling the gland cavi- ties, assuming a spherical shape, and becoming charged with fat granula- tions. The period of lactation being completed, the mammte take on their former charac
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