THE LACTEAL GLANDS. 



661 



Fig. 272. 



With respect to their structure, the lacteal glands, in all essential 

 particulars, completely correspond with the larger racemose glands, for 

 instance the parotid and the pancreas. Each gland consists of 15-24 

 or more, irregular, flattened lobes, % to 1 inch wide, with a rounded, 

 angular outline, which, although their cavities are quite distinct from 

 each other, cannot externally always be definitely separated. Each is 

 composed of a certain number of smaller and smallest lobules, and 

 these, lastly, of (/land-vesicles. The latter are rounded, or pyriform, 

 0-05-0-07 in size, with a distinct constriction between them ; and the 

 smallest excretory ducts, as for instance, in the small mucous glands, 

 and as everywhere else, are formed of a structureless membrane and 

 tessellated epithelium, which, at the time of lactation, undergoes pecu- 

 liar metamorphoses. All these glandular elements are surrounded by 

 dense, white connective tissue, particularly abundant between the gland- 

 vesicles and smaller lobules, and 

 are united into a compact, large 

 glandular mass, which is ultimate- 

 ly covered by a quantity of adi- 

 pose tissue, and in part by the 

 skin. The lacteal glands are, 

 properly speaking, not simple 

 glands, but like the lachrymal, 

 aggregations of these. From each 

 glandular lobe, by the coalescence 

 of the excretory ducts of the smal- 

 ler and larger lobules, there ulti- 

 mately proceeds a shorter or 

 longer duct, 1-2 lines in diameter, 

 the lacteal duct or canal (ductus 

 lactiferus s. galactophorus), which 

 running towards the nipple, dilates 

 beneath the areola, into an elon- 

 gated sacculus, 2-4 lines wide, the lacteal sac or receptacle (sacculus s. 

 sinus lactiferus) ; afterwards contracting to 1 or J a line, it bends round 

 into the nipple, and ultimately opens, at its apex, in an independent 

 orifice, not more than 1-3-1-5 of a line in diameter, between the papillae 

 which exist in that situation. All these excretory ducts, besides an 

 epithelium, which in the largest of them presents cylindrical cells, 

 0-006-0-01 of a line long, and in the finer ramifications, rounded poly- 

 gonal smaller cells, and a homogeneous layer beneath them, als6 possess 

 a white dense fibrous membrane, longitudinally plicated in the larger 

 canals, in which I have hitherto been unable to detect any indubitable 



FIG. 272. A few of the smallest lobules of the lacteal gland of a puerperal female, with 

 their ducts, magnified 70 diameters. After Langer. 



