248 



MAMMARY GLANDS. 



We must next direct our attention to the 

 internal structure of the breast, first as regards 

 the protective arrangements. 



The fascia enveloping the breast, like the 

 tunica albuginea of the testicle, sends in pro- 

 cesses to support and protect the secreting 

 membrane of the gland and suspend it in its 

 situation. These processes are all denomi- 

 nated by Sir Astley the ligamenta suspensoria, 

 (Jig. 73). " The ends of these ligaments are 

 spread out and incorporated with the posterior 

 surface of the skin, and give it whiteness and 

 firmness." 



The secerning portion of the gland con- 

 sists of the minute cells which were referred to 

 at the commencement of this article, and we 

 learn from Sir A. Cooper that " their size in 

 full lactation is that of a hole pricked in paper 

 by the point of a very fine pin ; so that 

 the cellules, when distended with quicksilver 

 or milk, are just visible to the naked eye. 

 (Fig. 74.) They are rather oval than round, 



Fig. 74. 



Shews the origin of the ducts 

 from the milk celh, (injected 

 with quicksilver and magnified 

 four times.) 



being slightly elongated where the bunch of 

 the lactiferous tubes springs from them ; but 

 they appear more rounded to quicksilver, and 



when distended with milk than when filled 

 with wax." 



These minute cells or cellules are bound up 

 together so compactly as to form little bodies 

 or " glandules" varying in size from a pin's 

 head to that of a small tare. When separated 

 from the rest of the gland but attached to the 

 mammary duct, which originates in separate 

 branches from its cellules, it presents a race- 

 mose appearance. 



From the cellules the milk-tubes originate in 

 a radiate form by small and numerous branches. 

 They increase in size by repeated unions, and 

 terminate by five or six branches in dilatations 

 the " reservoirs 7 ' of Sir Astley. " These recep- 

 tacles are of a conical form (see Jig. 75) like 

 the mammillary tubes, and they begin from 

 the extremities of the larger branches of the 

 milk-tubes and terminate in the straight ducts 

 of the nipple." 



In most other classes of the Mammalia these 

 reservoirs are much larger than in man, where 

 they hardly deserve the title, and in the cow 

 they are so capacious as to be capable of con- 

 taining at least a quart. 



The different ducts of these reservoirs take a 

 straight course, diminishing in size, through 

 the nipple to its extremity, where they terminate 

 in a cribriform manner, with very contracted 

 orifices, varying in size from those of a bristle 

 to a common pin. Their number is about 

 twenty. 



Arteries. The mamma receives its sup- 

 ply of blood from branches of the internal 

 mammary, axillary, and intercostal arteries. 

 Sir Astley divides them into anterior and pos- 

 terior, the former passing from the axillary 

 artery and the latter from the internal mam- 



Fig. 75. 



A view of the preparation of six milk tubes, injected from the nipple. 



a, a, a, the straight or mammillary tnhcs, proceeding from the apex of the nipple. 



b. b, b, the reservoirs or dilatations of the ducts, 

 r, <, c, the branches of the mammary ducts. 



(/, '/, <l, (I, their glandules. 



