SKIN-GLANDS. 



203 



tlieir extraordinary size, these important organs are merely 

 large sebaceous skin-glands (Plate V. Fig. 16, nid). The 

 milk h produced by liquefaction of the fatty milk-cells 

 within the branched milk-gland pouch (Fig. 215, c), just 

 as the sebaceous matter of the skin^ and the fatty matter 

 of the hair are produced by the breaking up of fatty 

 sebaceous cells within the sebaceous skin-glands. The 

 excretory passages of the milk -glands enlarge into sac-like 

 milk-ducts (h), which again become narrower (a), and open, 

 through from sixteen to twenty -four minute apertures, into 

 the nipple of the breast. The first rudiment of this large 

 and complex gland is a, very simple conical plug in the 



Fig. 215. — The breast of the female in- section : c, grape-like^ glandnlar 

 obnles ; h, enlarged milk-ducts ; a, narrow excretory ducts, opening* through 

 he breast-nipple. (After H. Meyer.) 



Fig. 216. — Milk-glands of a new-bom child : a, original central gland 

 6, smaller, and c,. larger branches of the latter. (After Langer.) 



