302 



HISTOLOGY 



tubular gland. The branching has been so extensive that the lumina 

 which constitute the so-called Hie capillaries have been very greatly 



reduced and branched. These bile 

 capillaries may have a wall of five 

 ca p or six surrounding cells or of but two 

 cells. The hepatic cells are cubical 

 to polyhedral. Their faces approxi- 

 mate to form the lumina or bile capil- 

 laries. The bile capillaries send 

 intra-cellular branches into the cyto- 

 plasm of the cells (Fig. 273). The 

 cytoplasm is seen to be vacuolated 

 when free of glycogen and pigment 

 granules. The nuclei are spherical 

 and lie near the center of each cell. 

 Chromatin is very conspicuous in 

 FIG. 273-- Goigi preparation of a portion of these nuclei. It forms large deeply 



frog's liver. Cells and nuclei in outline, staining bodies Suspended Upon a 

 b.cap., intercellular bile capillary; b.ch. ... . , 1-1 i 



intra-cellularbile channels. X 75 . lmm g reticulum ; a Spherical micleo- 



lus is usually to be seen within the 



nucleus (Fig. 274). Canals in the cytoplasm empty into the bile cap- 

 illaries. The bile capillaries converge to form hepatic ducts, which 

 lead off from the lobes of the liver to the bile duct. 



Technic. These tis- 

 sues are easy to handle bl c, 

 for general work and 

 very few special processes 

 are necessary. Owing to 

 the presence of food ma- 

 terial in the cavities, and 

 especially to the fact that 

 the tissues themselves 

 secrete digestive juices 

 from which they are 

 immune only as long as 

 life exists, it can be seen 

 that they must only be 

 taken from the freshest 

 of newly killed animals 

 and must be immediately 

 placed in the fixative. 

 This, however, often causes another trouble, the contraction and shrink- 

 ing away of the still living inner parts from the already fixed and stiffened 



B 



FIG. 274. Three liver cells from the salamander Crypto- 

 branchus. They show, in A, B, and C, three successive 

 stages of pigmentation, bl.c., blood cell. 



