THE LIVER 



185 



with clear or vacuolated cyt()])lasin. The smaller hile ducts are of 

 low cuboidal cells that have the same embryonic orifjin as the 

 secretintj; cells. Between adjacent end-pieces is a small amount of 

 connective tissue supportinj^; sinusoids similar to those of the mam- 

 malian liver. Amonj? the secretinoj cells are o;rou])s of pij,nnent 

 cells. The l)ile ducts are at first c()mi)osed of cuboidal cells, the 

 larger branches are formed of cohnnnar cells, and the still larger 

 branches have stratified columnar epithelium. In the Urodeles, 

 the tissue of the inner zone of the capsule contains hemocytoblasts 

 and neutro])hil and eosinophil myelocytes, and acts as a hemapoietic 



Fig. 119.— Section of liver of Amblystoma, showing rows of lange polyhedral hepatic 

 cells separated by sinusoids. Cells filled with pigment are also shown. 



center. The mammalian li^•er has this property only during early 

 embryonic life. 



The reptilian liver has the appearance of a compound tubular 

 gland also. The secreting end-pieces are comi)osed of large ]x)ly- 

 hedral cells. The bile ducts resemble in general those of a mam- 

 malian salivary gland. Between adjacent tulniles is a prominent 

 capillary network. In the connective tissue between lobules can 

 be found the so-called portal canals, i. e., an artery, a Aein, and a 

 bile duct. 



The Mammalian Liver.— This is the largest gland in the body and 

 lies below the diaphragm in the upper region of the abdominal ca\'ity. 

 The fibroelastic connective sheath, or capsule of Glisson, completely 

 surrounds the liver. At the hilum, where the blood vessels enter 



