122 LACTIFEROUS GLANDS. 



and which contain the ultimate glandular arrangement. The 

 acini themselves consist of very small oblong vesicles, united 

 by cellular substance, and by the common blood vessels; and are 

 said to be very apparent by the aid of a microscope in a lac- 

 tescent gland.* 



Excretory Ducts (Ductus Galactophori, Lactiferi) of this 

 gland are numerous.f They are of an arborescent shape, and 

 begin by very fine extremities or ramuscles in the acini; the ra- 

 muscles from several acini coalesce into a larger branch; seve- 

 ral branches unite to form one still larger, and so on, succes- 

 sively, until a lactiferous duct, constituting, as it were, the body 

 of the tree, is formed by this assemblage. These trunks vary 

 considerably in size, according to the number of tributary 

 branches, and having got towards the centre of the gland near 

 the nipple, from two to four of them, according to Cuboli,run into 

 a common stock or root, called a Lactiferous Sinus. These 

 Sinuses are in all about fifteen: they are only a few lines long, 

 and differ in size; some not being larger than a lactiferous duct, 

 while others have a diameter of from two to three lines. The 

 sinus at the end next to the nipple terminates in a sort of round- 

 ed cul-de-sac; but from the extremity of the sac a conoidal tube 

 arises which runs through the nipple, and conducts the milk: the 

 point of this tube is very fine, and ends on the top of the nipple. 

 This tube, from its shape, is suited to the retention of milk: 

 in addition to which, it is sometimes dilated in the middle, is 

 curved when the nipple is not in a state of erection or stretched 

 out, and terminates by an external orifice, which is so small as 

 to be seen with difficulty by the naked eye. 



The excretory ducts of the breast, under which term may be 

 comprehended the lactiferous ducts, the sinuses, and the conoi- 

 dal tubes in the nipple, are formed by a soft, thin, and semi-trans- 

 parent membrane, very capable of extension and of contraction. 

 The trunks generally go deeply through the substance of the 

 gland, and are tortuous, but do not anastomose laterally with 

 one another; whence it happens that the lobes and lobules of 



* Marjolin, Manual D'Anat. J. F. Meckel, Manual D'Anat. 

 j- Alex. Kolpin, Diss. Inaug 1 . cle Struct. Mam. Cuboli, Append, ad Septemd. 

 Tab. Santorini. Girardi, Append- ad Septemd. Tab. Santorini. 



