STRUCTURE OF MAMMARY GLAND. 



071 



the lactiferous tubes proceed to distinct lobuli in each glandule ; so that when 

 a branch of a mammillary tube has been filled with injection, its attached 

 lobules, if separated from each other by long maceration, are like a bunch 

 of fruits clustered upon a stalk (Fig. 368). When the lactiferous tubes are 



FIG. 307. 



Distribution of the Milk-ducts in the Mamma of the Human Female, during lactation ; tne ducts 



injected with wax. 



pursued to their ultimate distribution, they are found to terminate in folli- 

 cles, whose size, in full lactation, is that of a hole pricked in paper by the 

 point of a very fine pin, so that, when distended with quicksilver or milk, 



FIG. 368. 



FIG. 3G9. 



FIG. 368. Termination of portion of Milk-duct in a cluster of follicles ; from a mercurial injection ; 

 enlarged four times. 

 FIG. 369. Ultimate follicles of Mammary gland, with their secreting cells, a, a, and nuclei, 6, b. 



they are just visible to the naked eye; at other times, however, the follicles 

 do not admit of being injected, though the lactiferous tubes may have been 

 completely filled. They are lined by a continuation of the same membrane 



