132 PRACTICAL HISTOLOGY fv. 



Many more or less complete villi may be seen. Along the edge 

 of the villus, covered by its layer of columnar cells, the clear disc 

 is readily seen, and by focussing the surface of a villus the nucleated 

 mosaic formed by the ends of the cells, with the rounded mouths 

 of the goblet-cells, come into view. 



(ft.) If the animal was killed whilst its food was undergoing 

 digestion, refractive fatty granules may be seen in the protoplasm 

 of the cells. 



(c.) End View of the Cells. Move the preparation until a 

 fragment of detached epithelium is seen showing the free ends of 



the cells directed towards the observer 

 (fig. 92, d). 



(d.) Note in such a group of cells the 

 polygonal outlines of the ends of the 

 cells, and in each polygonal area a large 

 rf spherical nucleus, which appears almost 



FIG. 92. a, b. Isolated Columnar to fill the area. A nucleolus can often 



Epithelial Cells from the Small ^ TT _ j ^ i 



Intestine of Cat ; c. Goblet-cell ; L Ln - Ild y lj 



d. Ends of columnar cells and the rounded opening of a goblet-cell. 



open mouths of goblet -cells -T-I * n ^ * j_i 



directed towards observer. Focus carefully and notice the appear- 

 ance of the goblet-cell. When the open 



mouth is in focus, it is seen as a circle of small diameter, and on 

 depressing the tube the broad part of the cell comes into view (fig. 

 92, d). 



(e.) Amongst the cells may be found isolated goblet-cells (fig. 

 92, c). Each cell has an open mouth, while the lower part of the 

 cell contains a nucleus embedded in a small quantity of protoplasm. 



2. Isolated Columnar Epithelium of Newt (H). Mount in 

 glycerine a small quantity of isolated columnar cells which have 

 been dissociated by maceration in dilute alcohol and subsequently 

 stained with picro-carmine. Place a short length of hair under the 

 cover-glass. 



The small intestine of a rabbit may be used, but far larger cells 

 are obtained from the intestine of a newt. Macerate the whole 

 intestine in dilute alcohol for twenty-four hours and stain in bulk 

 in picro-carmine for at least another twenty-four hours. On 

 scraping the mucous surface, the cells are detached and diffused in 

 formic glycerine. 



(a.) Observe the large, tall, columnar cells, often tapering to a 

 point at their lower end, the red-stained nucleus, and the clear 

 striated disc. The nucleus usually exhibits a distinct nucleolus 

 (fig. 93), and sometimes two nuclei are present. Sometimes two 

 nucleoli are seen in a nucleus, and the cell itself may be branched 

 at its fixed extremity. 



If the intestine of a newt be macerated for twenty-four hours in 



