150 



NORMAL HISTOLOGY. 



medullated fibrils, which ramify throughout the substance of the 

 liver and terminate in minute twigs among its epithelial cells. 



The epithelial cells of the liver have a cubical shape, the grooved 

 and other surfaces that come in contact with neighboring cells being 

 flat, while the remaining surfaces may be somewhat rounded. The 

 cytoplasm is granular, and, except after a considerable period of 

 starvation, more or less abundantly infiltrated with irregular gran- 

 ules and masses of glycogen and globules of fat (Fig. 129). The 



FIG. 129. 



Portion of hepatic lobule of the rabbit ; cells infiltrated with glycogen. (Barfurth.) The 

 animal had been fed for twenty-four hours on wheat-bread, to promote the storage of gly- 

 cogen within the liver-cells. The cells in close proximity to the central vein contain 

 the largest amount of glycogen, which appears to fill the cytoplasm. Further from the 

 central vein the cells contain less glycogen, which is most abundant in that portion of 

 the cell turned toward the centre of the lobule. Fat-globules are most abundant in the 

 cells at the periphery of the lobule. No fat-globules are represented in this figure. 



glycogen dissolves out of the cells during the ordinary processes of 

 fixation and hardening preparatory to the preparation of sections, 

 leaving spaces in the cytoplasm, which cause it to have a coarsely 

 reticulated appearance in cases where the glycogen was abundant. 

 This reticulation would render it impossible to distinguish the 

 minute intracellular bile-passages. Each cell has a round vesicular 

 nucleus near its centre. In rare instances two nuclei may be found 

 in a single cell. 



It will, perhaps, make the structure of the liver a little more 

 comprehensible if it is stated that the liver of some of the lower 

 animals is a tubular gland, the tubes of which are lined with a layer 



