444 



MANUAL OF HISTOLOGY. 



blood-vessels. Eckhard has given the most elaborate descrip- 

 tion of the nerve-supply of the human mamma. 



Structure of fully expanded gland. Immediately before, 

 during, and after lactation, the mamma appears as a distinctly 

 lobulated organ, having a pinkish or yellowish hue, and resem- 

 bling in consistence the human pancreas or salivary gland. 



The different lobuli are made up of numerous ultimate 

 acini, having, as a rule, a rounded, pyriform, or slightly poly- 

 hedral shape. They are of nearly uni- 

 form size, and are closely placed, being 

 separated from one another by only 

 sparing amounts of connective tissue, 

 and the capillary vascular channels 

 therein contained. Elastic fibres and 

 smooth muscle-cells also occur, though 

 not constantly, between the alveoli of 

 the lobules. Lymphoid elements, as 

 well as branched connective-tissue cor- 

 puscles, are always encountered there 

 in greater or less abundance. In addi- 

 tion to these elements, large granular 

 corpuscles containing nuclei are found. 



Via. 190. Transverse section 

 through the terminal vesicles of the 

 gland in a nursing woman, showing 

 interalveolar capillaries. Langer. 



They are most numerous along the 



course of the blood-vessels, and appear 

 to be identical with the so-called plasma cells of Waldeyer. 

 Creighton, however, also describes similar cells in the interior 

 of the alveoli,' and believes that both are identical, maintain- 

 ing that they are derived from the acinous epithelium. 



According to this author's description, such cells are "not 

 infrequently seen in the tissue outside a lobule in rows three 

 or four deep ; again, they are found in the interfascicular spaces 

 among the lymphoid-cells," that have been already mentioned. 

 These large, granular, and nucleated corpuscles are said to be 

 filled with a bright yellow or golden pigment. Now, Creighton 

 has pointed out that the periodical subsidence of the mammary 

 function is accompanied by the formation of much corpuscular 

 waste material. And the production of these remarkable yel- 

 low cells, which finally leave the gland by way of the lymph- 

 vessels, is, according to him, but a final phase of this process. 



The mammary epithelium which paves the acini has been 

 variously described as consisting of flat polyhedral (Reinhard) ; 



