I 4 



This preparation gives you a surface view of stratified 

 pavement epithelium. Observe the flat nucleated cells, 

 cemented together by a small amount of intercellular 

 cement substance. Sketch a small portion of the field as 

 seen under the high power. 



(d) Cross Section of Stratified Pavement Epithe- 



lium. ^ 



A small portion of the soft palate or the oesophagus was 

 hardened in a saturated aqueous solution of mercuric chloride or 

 absolute alcohol, stained in borax or alum carmine, embedded in 

 paraffin, and sectioned. Mount in balsam. 



Observe the several layers of epithelial cells, and their 

 change in shape as they are traced outwards. In the low- 

 est layer, the cells are columnar, in the following polygonal, 

 while in the outermost layers they are flattened. Notice 

 the change in the shape and structure of the nuclei of the 

 cells of the different layers. Sketch as seen under high 

 power. 



(e) Isolated Transitional Epithelial Cells Stained 



in Haematoxylin and Eosin. 



The bladder of a large dog was distended with 33% alcohol 

 before removing, the urethra was tied. The bladder was then placed 

 in 33% alcohol, where it remained 24 hours. It was then cut into 

 small pieces. Scrape the epithelial surface of one of the small 

 pieces, place the scraping on a cover glass, and tease thoroughly. 

 After teasing dry the preparation over a flame. Stain in hsema- 

 toxylin and eosin, and mount on balsam. 



Examine under high power. Cells of various shapes 

 will be seen. Some are large flat scales^with one or two 

 nuclei ; others are pear-shaped, spindle-shaped, or triangu- 

 lar. The pelvis of the kidney, the ureter, and the bladder, 

 are lined with transitional epithelium. Sketch the several 

 forms of epithelial cells found. 



(f) Cross Section of Transitional Epithelium. 



Small pieces of the bladder of a dog were hardened in abso- 

 lute alcohol, stained for 24 hours in Delafield's hsematoxylin (one 

 part of the stain to ten parts of distilled water), embedded in 

 paraffin, and sectioned. Fix to the slide with albumen fixative, 

 and mount in balsam. 



