STEUCTUEE OF THE MAMMA. 



1003 



lobules, especially as contrasted with the adjacent fat, is of a pale, reddish 

 cream-colour, and is rather firm. It is composed principally of the vesi- 

 cular commencements of the lactiferous ducts, which appear like clusters of 

 minute rounded cells, having a diameter from ten to thirty times as great 



Fig. 696. 



Fig. 696. DISSECTION OP THE LOWER HALF OF THE FEMALE MAMMA DURING THE 

 PERIOD OF LACTATION (from Luschka). f 



In the left-hand side of the dissected part the glandular lobes are exposed and partially 

 unravelled ; and in the right-hand side, the glandular substance has been removed to 

 show the reticular loculi of the connective tissue in which the glandular lobules are 

 placed : 1 , upper part of the mammilla ; 2, areola ; 3, subcutaneous masses of fat ; 

 4, reticular loculi of the connective tissue which support the glandular substance and con- 

 tain the fatty masses ; 5, one of three lactiferous ducts shown passing towards the 

 mammilla where they open ; 6, one of the sinus lactei or reservoirs ; 7, some of the 

 glandular lobules which have been unravelled ; 7', others massed together. 



as that of the capillary vessels by -which they are surrounded. These cells 

 open into the smallest branched ducts, which, uniting together to form 

 others of larger size, finally end in a single excretory canal correspond- 

 ing to one of the chief subdivisions of the gland. The canals proceeding 

 thus from the principal lobes composing the gland are named the galacto- 

 phorous ducts, and are from fifteen to twenty in number ; they converge 

 towards the areola, beneath which they become considerably dilated, espe- 

 cially during lactation, so as to form sacs or sinuses two or even three lines 

 wide, which serve as temporary though small reservoirs for the milk. At 

 the base of the nipple all these ducts, again reduced in size, are assembled 

 together, those in the centre being the largest, and then proceed side by 

 side, surrounded by areolar tissue and vessels, and without communicating 

 with each other, to the summit of the mammilla, where they open by sepa- 

 rate orifices ; these orifices are seated in little depressions, and are smaller 

 than the ducts to which they respectively belong. The walls of the ducts are 

 composed of areolar tissue, with longitudinal and circular elastic filaments. 



