COLUMNAR EPITHELIUM. 



133 



5 per cent, ammonium chromate, then the nuclei and cell-body show 

 a distinct h'brillar structure. 



III. Glandular Epithelium occurs in the secretory glands, e.g., 

 liver, pancreas, salivary, gastric, intestinal, and other glands. Neces- 

 sarily it must vary very greatly in shape and in its functions. 



3. Secretory or Glandular Epithelium of Liver. With a 

 clean scalpel scrape the cut surface of the liver of an animal just 

 killed, e.g., a rat. Place the scrapings in dilute alcohol (twenty- 

 four hours), pour off the alcohol and cover it with picro-carmine 

 (twenty-four hours). 



Liver-Cells (H). (a.) Examine the isolated cells in glycerine 

 with the usual precautions. Observe the cubical cells, which may 

 be isolated or adhering in groups of two or three. The granular 



FIG. 93. Isolated Columnar 

 Epithelial Cells from the 

 Newt's Intestine. Dilute 

 alcohol and picro-car- 

 mine, x 300. 



FIG. 94. Isolated Hepatic Cells, d. With two 

 nuclei ; b. Oil-drops ; c. Isolated nucleus of a 

 cell. Teased fresh. 



protoplasm is stained yellowish, and each cell has a spherical bright- 

 red nucleus. The protoplasm may contain globules of oil, and 

 occasionally two nuclei may be seen in a cell, especially in the liver- 

 cells of a young rat (fig. 94). 



(/>.) If the cells be much broken up, liberated nuclei and granules 

 of oil, and sometimes red blood-corpuscles, are seen in the field. 



((-.) Acetic acid clears up the protoplasm, makes the nucleus more 

 distinct ; it does not affect any fatty particles, but merely makes 

 them more evident. 



Sulpho-cyanide of potassium (5 per cent.) is an excellent medium 

 for maceration of the liver-cells. The plexus of fibrils in the nuclei 

 is thus rendered visible. 



IV. Transitional Epithelium occurs in the urethra, urinary 

 bladder, ureters, and pelvis of the kidney. It is confined to the 

 gcnito-urinary mucous membrane; It consists of several (2-3-4) 

 layers of cells. The superficial cells are large and flattened 

 (especially if the bladder has been kept distended), often with two 

 nuclei, and with depressions on their under surface produced by the 

 large rounded ends of the cells of the next layer. The cells of the 



