MAT, 



20 9 .] 



OF THE LACTEAL GLANDS. 



471 



Fi 191 



-.-TN 



arc roundish or pyriform, 0-05'" to 007'" in size, and are marked 



off by a distinct constriction from the finest excretory ducts (move 

 decidedly, for example, than in the small mucous glands). Here, 

 as elsewhere, the gland-vesicles are composed of a structureless 

 membrane and a pavement-epithelium; the latter undergoes pe- 

 culiar metamorphoses at the period of lactation. All the gland- 

 elements are surrounded and united into a compact glandular mass 

 by a dense, white, connective tissue that is very abundant, espe- 

 cially between the acini and 

 smaller lobules; and the 

 whole is covered bv a large 

 quantity of adipose tissue, 

 and, on one aspect, by the 

 skin. The lacteal glands 

 are not, properly speaking, 

 simple glands, but, like the 

 lachrymal glands, aggrega- 

 tions of such ; that is to 

 say, by the coalescence of 

 the excretory ducts of the 

 smaller and larger lobules, 

 there arises eventually from 

 each lobe a shorter or longer 

 duct, 1 to 2 lines wide, the 

 lacteal duct or canal, ductus 

 lactiferus s. galartovhorus, 

 which runs sepaii ^y to- 

 wards the nipple, always 

 receiving smaller ducts in its course. Beneath the areola, the duct 

 enlarges to an elongated sac, 2 to 4 lines wide, the sacculus s. sinus 

 lactiferus, and then, diminished to 1, or even ^ a line in diameter, 

 turns into the nipple, and ultimately opens independently upon its 

 apex by an aperture 1'" to £-'" in width, situated between the little 

 eminences which are here seen. The epithelium, in the thickest 

 ducts, presents cylindrical cells o , oo6'" to o - oi'" in length ; but, in 

 the liner ramifications, on the other hand, smaller cells, roundish 

 or polygonal. Besides this epithelium and a homogeneous layer 

 beneath it, all the excretory ducts possess a white, dense, fibrous 

 coat, which is folded longitudinally in the larger canals; in this I 

 have not hitherto been able to detect undoubted muscular fibres, 

 but only a nucleated, longitudinal, connective tissue, with fine 

 elastic fibres. Ilenle, however (Jahresberickte, 1850, p. 41), as also 



Some of the smallest lobules of the lacteal gland of 

 a puerperal woman, with their ducts ; magnified 70 

 times. After Langer. 



