24 THE ESSENTIALS OF HISTOLOGY 



free border. The nucleus (ri) is oval and reticular. The lateral 

 borders of the cells are often somewhat irregular or jagged, the 

 result of the pressure of amoeboid lymph-cells, which are generally 

 found between the columnar cells, at least in the intestine. After a 



FIG. 21. A iunv OF COLUMNAR CELLS FROM THE INTESTINE OF THE RABBIT. 



Smaller cells are seen between the epithelium-cells, probably of the nature of white blood or lymph 



corpuscles. 



meal containing much fat the cells may be filled with fat-globules, 

 which become stained black in the osmic preparation. 



Some of the columnar cells contain mucigen, which may greatly 

 distend the part of the cell nearest the striated border.' When the 



FIG. 22. COLUMNAR EPITHELIUM-CELLS OF THE RABBIT'S INTESTINE. 



The cells have been isolated after maceration in very weak chromic acid. The cells are much 

 vacuolated, and one of them has a fat-globule near its attached end ; the striated 

 border (str) is well seen, and the bright disk separating it from the cell-protoplasm ; 

 n, nucleus with intranuclear network ; a, a thiimed-out wing-like projection of the cell 

 which probably fitted between two adjacent cells. 



mucigen is extruded as mucus, this border is thrown off, and the cell 

 takes the form of an open cup or chalice (goblet-cell, fig. 23). 



Columnar epithelium-cells are found lining the whole of the interior 

 of the stomach and intestines : they are also present in the ducts of 

 most glands, and sometimes also in their secreting saccules. The epi- 

 thelium which covers the ovary also has a modified columnar shape, 

 but cells having all the structural peculiarities indicated above are 

 found only in the alimentary canal and in its diverticula. 



Ciliated epithelium. The cells of a ciliated epithelium are also 

 usually columnar in shape (fig. 24), but in place of the striated border 

 the cell is surmounted by a bunch of fine tapering filaments which, 



