LESSON V. 

 EPITHELIUM (Concluded). 



(a) Isolated Columnar Epithelial Cells. 



The small intestine of a cat was opened, and macerated for 24 

 to 48 hours in 33% alcohol. Tease a small portion of the mucous 

 membrane in gum glycerine. 



Study under high power, and use one of the smaller 

 openings in the diaphragm. Observe the shape of the 

 cells, position and shape of nucleus, and the striated 

 border. Sketch as seen under high power. 



(b) Isolated Columnar Cells Stained in Heema- 



toxylin. 



Tease very thoroughly a small portion of the above on a 

 cover glass. Dry over the flame, stain in hsematoxylin, and mount 

 on balsam. 



Observe the columnar cells, the faintly striated proto- 

 plasm, the cuticular border, and the structure of the 

 nucleus. Sketch a few of the cells as seen under high 

 power. 



(c) Cross Section of Simple Columnar Epithelium. 



The small intestine of a cat was cut open, pinned out on a 

 cork, hardened in absolute alcohol, stained in Delafield's h^ema- 

 toxylin, and embedded in paraffin. Cross sections of the villi were 

 made. Fix to slide and mount in balsam. 



Under low power you will observe many small, nearly 

 round or oval patches of tissue. When one of these is 

 studied under high power, it will be found to be surrounded 

 by a single layer of columnar cells cemented together by a 

 small amount of intercellular cement substance. In the 

 intercellular cement a leucocyte is now and then found. 



Sketch as seen under high power. 

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