AREOLA. 123 



the gland are arranged into sections, each of which has its ap- 

 propriate excretory duct. In order to make a complete injec- 

 tion of the gland, each sinus must be separately injected through 

 its conoidal tube. This rule is not, however, of universa v l<ap- 

 plication, as in some experiments performed by the elder Meckel 

 upon women advanced in pregnancy and during lactation, he 

 succeeded in forcing mercury through one sinus, by its ramifi- 

 cations, into those of another: this route was supposed to have 

 been through the finest extremities of the ducts. The whole 

 gland itself may, however, from the infrequency of this circum- 

 stance, and from the difficulties and partial condition of these 

 anastomoses, rather be considered as a congeries of smaller 

 glands kept distinct by the interposition of cellular substance be- 

 tween their lobes; but joined, in one respect, by having the ter- 

 minations of their excretoy tubes collected into one bunch in 

 the nipple. This latter circumstance seems to be only a provi- 

 sion for the more convenient sucking of the infant. 



The excretory ducts are no where furnished with valves, 

 which accounts for the facility with which they may be injected 

 backwards from the nipple. An opinion was entertained by 

 Haller, and by other anatomists after him, that some of these 

 ducts originated in the surrounding cellular substance, but this 

 has keen refuted by the researches of Cuboli. Some anatomists 

 have thought that there is a direct communication between the 

 ends of the lactiferous tubes and the arteries, veins, and lym- 

 phatics. Mascagni, after a very successful injection of the gland, 

 whereby its vesicles were filled with quicksilver, not meeting 

 with such an occurrence, was induced to think that when the 

 communication did happen, it was produced by rupture. 



The Jlreola, 



In virgins is a rose-coloured circle, which surrounds the base 

 of the papilla or nipple. In women who have borne children, 

 or in those whose age is advanced, it becomes of a dark brown. 

 The skin of the areola is extremely delicate, and on its surface, 

 particularly in pregnant or nursing females there are from four 

 to ten tubercles, which sometimes form a regular circle near its 

 circumference, and in other subjects are irregularly distributed. 

 Each of these tubercles has near its summit three or four fora- 



