DISSECTING MANUAL. 



which is covered by wrinkled skin and surrounded by a colored 

 circular area (areola) ; on the areola are seen many small pro- 

 jections due to cutaneous glands. Each consists of glandular 

 tissue covered by fat. The glandular tissue (corpus mammae) 

 consists of fifteen to twenty distinct lobes which are connected 

 by fibrous tissue (stroma) ; each lobe has its own duct which 

 opens separately on the summit of the nipple. Each duct has 

 a small dilatation (ampulla, or sinus lactiferi). [1207] 



Thymus Gland. This is pinkish and consists of two lobes 

 of unequal size which are separated by a fissure. It ends above 

 in blunt prolongations which ascend into the neck, rarely as 

 far as the thyroid body. The thoracic portion lies in the su- 

 perior and anterior mediastina, close behind the sternum and 

 costal cartilages; it extends down to the fourth costal car- 

 tilage and is in contact with the pericardium, great vessels be- 

 hind, and pleural sacs. After the second year the gland slow r ly 

 diminishes in size, or it may remain stationary till puberty 

 when a rapid degeneration sets in but never becomes entirely 

 complete. [1218] 



Structure. It consists of lobules which are separated by 

 septa derived from its sheath. Each lobule consists of lym- 

 phoid follicles. A follicle consists of an outer cortical part, 

 and a central medullary part whose cells are less closely 

 packed. [1219] 



[140] 



